ALBERT

Description: 〈p〉Publication date: Available online 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): S. Monzani, A. Andreazza, M. Citterio, P. Fontana, M. Ianna, T. Lari, V. Liberali, F. Ragusa, C. Sbarra, A. Sidoti, A. Stabile〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Monochromatic X and gamma rays are a standard calibration tool for semiconductor detector. For finely segmented pixel detectors, like the ones foreseen for HL-LHC detector upgrades, the single pixel spectrum is affected by charge sharing across nearby pixels, due to diffusion and the finite range of photoelectrons, resulting in a low energy continuum below the photoelectric peak. In this paper a systematic simulation study will be presented. The shape of the transition between the photoelectric peak and the continuum is determined by diffusion and needs to be unfolded for a correct estimation of the energy resolution. Simulation results are compared with data collected with different high-resistivity CMOS devices with 50 × 250 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mi mathvariant="normal"〉μ〈/mi〉〈/math〉m〈sup〉2〈/sup〉 pixel size and photon energies between 13 and 60 keV. They show a good agreement, highlighting the potential usage of the whole single pixel spectrum to derive device characteristics.〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Sai Huang, Zhihao Wang, Qi Zhu, Xiaofei Shi, Xuejiao Wang, Xiaodong Li, Xudong Sun, Ji-Guang Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉RE(OH)〈sub〉2.94〈/sub〉(NO〈sub〉3〈/sub〉)〈sub〉0.06〈/sub〉·〈em〉n〈/em〉H〈sub〉2〈/sub〉O nanosquares were first employed as template to synthesize YVO〈sub〉4〈/sub〉:Ln luminescent crystallites (Ln = Eu, Sm, and Dy) via hydrothermal nanoconversion in the presence of NH〈sub〉4〈/sub〉VO〈sub〉3〈/sub〉. Product properties and the course of phase/morphology evolution were characterized in detail by XRD, SEM, TEM, FT-IR, TG, and optical spectroscopy. It was clearly demonstrated that the nanosquares templated vanadate crystallization, owing to structure similarity, but was accompanied by subsequent dissolution and reprecipitation. The resultant vanadate phosphors, mostly in the form of bundles containing platelike and fibrous crystallites, exhibited strong red emission at ∼618 nm for Eu〈sup〉3+〈/sup〉, orange-red emission at ∼604 nm for Sm〈sup〉3+〈/sup〉 and greenish yellow emission at ∼575 nm for Dy〈sup〉3+〈/sup〉 upon exciting the VO〈sub〉4〈/sub〉〈sup〉3−〈/sup〉 ligand. Dehydration at 500 °C further improved the emission by ∼2.5 times for Eu〈sup〉3+〈/sup〉 and ∼1.5 times for Sm〈sup〉3+〈/sup〉 and Dy〈sup〉3+〈/sup〉. The Eu〈sup〉3+〈/sup〉 (5 at%), Sm〈sup〉3+〈/sup〉 (1 at%) and Dy〈sup〉3+〈/sup〉 (1 at%) activators were analyzed to have quantum yields of ∼48, 9 and 16% and color coordinates of around (0.65, 0.33), (0.60, 0.39) and (0.38, 0.43) for their luminescence, and fluorescence lifetimes of ∼1.52, 1.40 and 0.89 ms for their dominant emissions, respectively. It is also interesting to find out that replacing only 15% of the total OH〈sup〉−〈/sup〉 and NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉 anions in the template by VO〈sub〉4〈/sub〉〈sup〉3−〈/sup〉 produced ∼20 times stronger Eu〈sup〉3+〈/sup〉 luminescence, indicating that VO〈sub〉4〈/sub〉〈sup〉3-〈/sup〉→ Eu〈sup〉3+〈/sup〉 energy transfer is very efficient. The protocol would be extendable to other types of functional rare-earth compounds.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838818339719-fx1.jpg" width="245" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Chunmu Guo, Qinghua Tian, Li Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nanostructure of titanium dioxide (TiO〈sub〉2〈/sub〉) has gained extensive attention in anode material field of lithium-ion batteries (LIBs) owing to its outstanding structure stability and improved safety over graphite. Herein, facilely controllable synthesis of interestingly spindle TiO〈sub〉2〈/sub〉 nanograins has been achieved by a one-pot hydrothermal and subsequent calcination approach, it is demonstrated that the grain size has a great effect on the electrochemical lithium storage kinetics of as-synthesized TiO〈sub〉2〈/sub〉 nanograins. As a result, the as-prepared TiO〈sub〉2〈/sub〉-0.05M with much smaller size exhibits greatly improved lithium storage performance, delivering a capacity of 120.5 mAh g〈sup〉−1〈/sup〉 after even 1000 cycles.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Xi Cheng, Shi Wei Xu, You Ming Lu, Shun Han, Pei Jiang Cao, Fang Jia, Yu Xiang Zeng, Xin Ke Liu, Wang Ying Xu, Wen Jun Liu, De Liang Zhu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Zn〈sub〉1-x〈/sub〉Cd〈sub〉x〈/sub〉O films with different Cd contents obtained by controlling the growth oxygen pressure (O〈sub〉p〈/sub〉) were deposited on both c-sapphire (Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉) substrates and p-GaN substrates, by means of the pulsed laser deposition (PLD) method. Photoluminescence (PL) measurement revealed that the variation of O〈sub〉p〈/sub〉 influenced the amount of Cd doping into Zn〈sub〉1-x〈/sub〉Cd〈sub〉x〈/sub〉O films deposited on Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉, leading tunable luminescence from the ultraviolet (UV) to blue emission extended to the green band. Then all the fabricated n-Zn〈sub〉1-x〈/sub〉Cd〈sub〉x〈/sub〉O/p-GaN heterojunction possessed good ohmic contacts and exhibited typical rectifying characteristic of the diode. Indeed, the high luminescence from the ZnCdO layer could be attained by inserting a MgO insulator to the heterojunction interface. The fabrication of tunable n-Zn〈sub〉1-x〈/sub〉Cd〈sub〉x〈/sub〉O/p-GaN heterojunction light-emitting diodes is available which was supported by the results of electroluminescence (EL) experiment.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Dina V. Deyneko, Ivan V. Nikiforov, Bogdan I. Lazoryak, Dmitry A. Spassky, Ivan I. Leonidov, Sergey Yu. Stefanovich, Daria A. Petrova, Sergey M. Aksenov, Peter C. Burns〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Novel red emitting phosphors Ca〈sub〉8〈/sub〉MgSm〈sub〉1–〈em〉х〈/em〉〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉7〈/sub〉:〈em〉x〈/em〉Eu〈sup〉3+〈/sup〉 with whitlockite-type structure were prepared by a high temperature solid-state reaction in air. Powder X-ray diffraction (PXRD), photoluminescence spectra, and fluorescence decay were used to characterize the structure and luminescence properties. All samples were found to have the expected rhombohedral structure with 〈em〉R〈/em〉〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mrow〉〈mover accent="true"〉〈mn〉3〈/mn〉〈mo〉¯〈/mo〉〈/mover〉〈/mrow〉〈/math〉〈em〉c〈/em〉 space group. The non-polar space group is also confirmed by a photoluminescence study. This space group allows forbidden transitions for Eu〈sup〉3+〈/sup〉. The presence of only one Shtark component in 〈sup〉5〈/sup〉D〈sub〉0〈/sub〉–〈sup〉7〈/sup〉F〈sub〉0〈/sub〉 confirms the presence of only one non-equivalent site containing Eu〈sup〉3+〈/sup〉 ions. The high intensity of the transition ratio 〈sup〉5〈/sup〉D〈sub〉0〈/sub〉–〈sup〉7〈/sup〉F〈sub〉2〈/sub〉/〈sup〉5〈/sup〉D〈sub〉0〈/sub〉–〈sup〉7〈/sup〉F〈sub〉1〈/sub〉 establishes the strongly disordered environment of the Eu〈sup〉3+〈/sup〉 ions. Thus, 〈em〉M〈/em〉1–〈em〉M〈/em〉3 sites in the host matrix are occupied by Ca〈sup〉2+〈/sup〉, Sm〈sup〉3+〈/sup〉, and Eu〈sup〉3+〈/sup〉 ions, whereas 〈em〉M〈/em〉5 is fully occupied by Mg〈sup〉2+〈/sup〉. The optimal concentration was found with 〈em〉x〈/em〉 = 0.75 in Ca〈sub〉8〈/sub〉MgSm〈sub〉1–〈em〉х〈/em〉〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉7〈/sub〉:〈em〉x〈/em〉Eu〈sup〉3+〈/sup〉 phosphors. The emitting of Sm〈sup〉3+〈/sup〉 was depressed due to the high intensity of Eu〈sup〉3+〈/sup〉 luminescence; however, the contribution of Sm〈sup〉3+〈/sup〉 is manifested in the energy transfer process and shift of CIE coordinates. Furthermore, the CIE chromaticity coordinate of 〈em〉as-prepared〈/em〉 Ca〈sub〉8〈/sub〉MgSm〈sub〉0.25〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉7〈/sub〉:0.75Eu〈sup〉3+〈/sup〉 (〈em〉x〈/em〉 = 0.650; 〈em〉y〈/em〉 = 0.345) is close to the standard red-emitting point (〈em〉x〈/em〉 = 0.67, 〈em〉y〈/em〉 = 0.33). The experimental data indicate that Ca〈sub〉8〈/sub〉MgSm〈sub〉1–〈em〉х〈/em〉〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉7〈/sub〉:〈em〉x〈/em〉Eu〈sup〉3+〈/sup〉 upon excitation by near-UV radiation is a promising red phosphor for white-light-emitting diodes.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838818339999-fx1.jpg" width="131" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Wanwu Ding, Chen Xu, Xingang Hou, Xiaoyan Zhao, Taili Chen, Wenjun Zhao, Tiandong Xia, Jisen Qiao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The new type of Al-Ti-C-La master alloy was prepared by commercial pure Al, Ti powder, graphite powder, Al powder and La〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 powder by aluminum melt in-situ reaction method. The microstructure and the effect on commercial pure aluminum of Al-Ti-C-La master alloy have been studied by means of X-ray diffraction (XDR), scanning electron microscopy (SEM) equipped with energy-dispersive spectrometry (EDS). The synthesis thermodynamics and kinetics of Al-Ti-C-La master alloy were analyzed. The experiment shows that Al-Ti-C-La master alloy is composed of Al, Al〈sub〉3〈/sub〉Ti, TiC and Ti〈sub〉2〈/sub〉Al〈sub〉20〈/sub〉La. The refining performance of the prepared Al-Ti-C-La master alloy is obviously better than that of Al-Ti-C master alloy when the addition of rare earth oxide La〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 is 10 wt% and the preparation temperature is 930 °C. The analysis of thermodynamic calculation and the process of kinetics demonstrate that, in the preparation process of Al-Ti-C-La master alloy, firstly, Al reacts with Ti to produce Al〈sub〉3〈/sub〉Ti, C reacts with Ti and Al〈sub〉3〈/sub〉Ti to form TiC based on the aluminothermy reaction. Rare earth oxide La〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 and C powder react with Ti powder and O〈sub〉2〈/sub〉 in the air occur to generate CO, TiC, [La] atoms and LaC〈sub〉2〈/sub〉. [La] atoms adsorb on the surface of Al〈sub〉3〈/sub〉Ti to form the new rare earth compounds Ti〈sub〉2〈/sub〉Al〈sub〉20〈/sub〉La.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Changmeng Huan, Xinyue Zhao, Xiudi Xiao, Yuan Lu, Shuai Qi, Yongjun Zhan, Lingzhi Zhang, Gang Xu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, the V〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 nanoparticles (NPs) with ultrathin carbon shells were synthesized by a facile solvothermal process. The V〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 NPs were about 30 nm and contained a carbon shell of about 2 nm thick. The V〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 NPs were homogeneously dispersed and loosely packed. When used as anode material, the V〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 core-shell NPs showed a reversible capacity up to 525 mA h g〈sup〉−1〈/sup〉 at 200 mA g〈sup〉−1〈/sup〉 over 200 cycles with good cycle stability and rate capability. The excellent electrochemical performance promotes its practical application in lithium-ion batteries.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Honghong Jin, Guang Sun, Bo Zhang, Na Luo, Yanwei Li, Long Lin, Hari Bala, Jianliang Cao, Zhanying Zhang, Yan Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel chain-like nanostructure of Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 was successfully prepared via a facile and reliable oxalate sacrificial template route, in which coralloid cobalt oxalate (CoC〈sub〉2〈/sub〉O〈sub〉4〈/sub〉·2H〈sub〉2〈/sub〉O) precursor was first obtained through a room-temperature precipitation method and then used as sacrificial template to prepare Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 by annealing at 500 °C. Au nanoparticles-decorated Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 nanochains were also prepared by soaking the CoC〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 precursor in Au〈sup〉+〈/sup〉 solution before the annealing process. The prepared samples were characterized by XRD, FESEM, TEM, and N〈sub〉2〈/sub〉 adsorption-desorption. Results indicated that the pure and Au-decorated Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 nanochains were constructed by several end-to-end connected nanoparticles, and their specific surface areas were 28.42 m〈sup〉2〈/sup〉/g and 37.39 m〈sup〉2〈/sup〉/g, respectively. The gas sensing properties of the prepared samples were tested and compared. It was found that after being functionalized with Au nanoparticles, the Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 nanochains showed an improved TEA sensing performance, such as lower optimal working temperature, higher response, and faster response and recover speed. In addition, the Au/Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 sensor can also give a good linearity in the TEA concentration range from 10 to 200 ppm and considerable stability within 7 weeks, suggesting its potential application for quantitative detection of TEA. The improved gas sensing mechanism of the Au/Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 nanochain was discussed.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): V.A. Lysenko〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A modified version of the Sb-Sn phase diagram was proposed that includes both Sb〈sub〉2〈/sub〉Sn〈sub〉3〈/sub〉 and Sb〈sub〉3〈/sub〉Sn〈sub〉4〈/sub〉 compounds. Based on this modification, phase equilibria in the In-Sb-Sn system were calculated using a thermodynamic modeling approach. Thermodynamic models for the ternary liquid phase and solid solutions (SbSn) and (Sb〈sub〉2〈/sub〉Sn〈sub〉3〈/sub〉) were developed. The isopleths 〈em〉x〈/em〉〈sub〉Sn〈/sub〉 = 0.2, 0.5, 0.8, vertical sections 〈em〉x〈/em〉〈sub〉In〈/sub〉/〈em〉x〈/em〉〈sub〉Sb〈/sub〉 = 3:1, 1:1, 1:3, liquidus surface projection, and isothermal section at 473 K were calculated.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Hongyi Gao, Mengyi Jia, Keyi Dong, Liwen Xing, Xiao Chen, Dandan Jia〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A Sisal-Like TiO〈sub〉2〈/sub〉/Graphene-Like Carbon Sheets (SL-TiO〈sub〉2〈/sub〉/GLCSs) composite was fabricated via a facile one-pot self-assembling route at a two-phase interface. The ingenious P123 was introduced to serve a dual function of carbon precursor and structure-directing agent, which first assembled at the water/oil interfaces and subsequently was in situ carbonized to GLCSs. Then the sisal-like TiO〈sub〉2〈/sub〉 grew gradually on the GLCSs along the preferred direction. This process shows several advantages such as simple processes, mild condition, low cost and good combination of SL-TiO〈sub〉2〈/sub〉 and GLCSs. The combination of SL-TiO〈sub〉2〈/sub〉 with GLCSs significantly helps the adsorption of substrates as well as promotes electron-hole pair separation, exhibiting good photocatalytic activity towards degradation of methylene blue (MB) compared to the pristine SL-TiO〈sub〉2〈/sub〉 and commercial P25. This strategy opens up new perspectives for fabricating novel composites of nanooxides/GLCSs.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Zhennan Liu, Naiqin Zhao, Chunsheng Shi, Fang He, Enzuo Liu, Chunnian He〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Three-dimensional (3D) carbon networks decorated with Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 nanoparticles as lightweight and broadband electromagnetic (EM) wave absorber were 〈em〉in-situ〈/em〉 prepared via a simple and large-scale method, combining freeze-drying and high-temperature calcination processes. SEM and TEM results show that 3D carbon network/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 (3DC/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉) composites have interconnected 3D porous carbon networks with submicrometer-sized macropores, and the Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 nanoparticles are distributed uniformly on the 3D carbon networks. The EM wave absorption performance of 3DC/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 can be tuned by changing Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 contents. The 3DC/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 with about 38.2 wt% Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 exhibits excellent lightweight and broadband EM wave absorption property. The effective absorption bandwidth can reach up 5.95 GHz (11.2–17.15 GHz) at the thickness of 3.0 mm with only 20 wt% filler loading. The minimum RL of −37.8 dB was obtained at 6.95 GHz. The excellent EM wave absorption capability of 3DC/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 can be ascribed to good impedance matching, strong dielectric loss ability and unique 3D porous structure. This work demonstrates that the 3DC/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 with light weight, broad absorption bandwidth and large-scale production potential can be a promising absorber for practical application.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838818339768-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Dan Zhou, Li-Ping Xue, Ning Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Transition metal phosphides are promising anode materials for next-generation rechargeable sodium-ion batteries due to the high theoretical capacities. However, the inherent low conductivity and large volume expansion of transition metal phosphides during the repeated sodiation/desodiation process critically hinder their practical applications. Herein, we immobilize Ni〈sub〉2〈/sub〉P nanoparticles robustly in porous carbon sheet networks via the pyrolysis and 〈em〉in-situ〈/em〉 phosphatization of poly(acrylic acid)-Ni(NO〈sub〉3〈/sub〉)〈sub〉2〈/sub〉 gel. The resulted porous network structure, high conductivity, robust chemical combination and space confinement effect of the Ni〈sub〉2〈/sub〉P-carbon composite offer the electrode not only rigid structural stability for volume expansion over long-term cycling, but also large specific capacity and fast Na〈sup〉+〈/sup〉/electrons transfer kinetics. As a consequence, the composite delivers a large initial discharge capacity (932 mAh g〈sup〉−1〈/sup〉 at 50 mA g〈sup〉−1〈/sup〉), a high rate capability (77 mAh g〈sup〉−1〈/sup〉 at 3500 mA g〈sup〉−1〈/sup〉), as well as a significantly enhanced long cycle-life (146 mAh g〈sup〉−1〈/sup〉 after 1500 cycles at 500 mA g〈sup〉−1〈/sup〉). The excellent Na-storage performance makes the synthesized Ni〈sub〉2〈/sub〉P-carbon composite a sound anode material for advanced rechargeable SIBs.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Yu Jun Yang, Weikun Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This work presents a novel method for the self-assembly of reduced graphene oxide (rGO) on nickel foam (NF) and the subsequent electrodeposition of hierarchical Ni-Co double hydroxide (NiCo-DH) nanosheets (NS) on rGO as a supercapacitor electrode. The self-assembly of rGO on NF is achieved by the direct reduction of graphene oxide at 50 °C. NF is not only used as the support of rGO but also the reducing agent for the reduction of GO. As the battery-type electrode material for supercapacitor, NiCo-DH supported on rGO modified NF (Ni-Co DHNS@rGO-NF) displays an ultrahigh areal capacity of 5.820 C cm〈sup〉−2〈/sup〉 at 20 mA cm〈sup〉−2〈/sup〉, a 100% coulombic efficiency and a 78% capacity retention after 2000 cycles at 100 mA cm〈sup〉−2〈/sup〉. An hybrid supercapacitor (HSC) is also assembled based on Ni-Co DHNS@rGO-NF as the positive electrode and active carbon (AC) as the negative electrode. The ASC exhibits a prominent energy density of 45.83 Wh kg〈sup〉−1〈/sup〉 at a high power density of 396.15 W kg〈sup〉−1〈/sup〉. The excellent electrochemical performance is attributed to the large surface area of the hierarchical NiCo-DH nanosheets array and the synergistic effect between Ni-Co DHNS and rGO.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Kodai Maeda, Satoshi Suzuki, Kyosuke Ueda, Tomonori Kitashima, Somesh Kr. Bhattacharya, Ryoji Sahara, Takayuki Narushima〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper reports the first study of the oxidative behavior of Si-containing Ti-6Al-4V alloys in air. The alloys were studied in the temperature range 910–1210 K for a maximum period of 518.4 ks, and their tensile properties at room temperature are reported. The addition of Si decreased the total mass gain during oxidation and enlarged the region in which the mass gain obeyed the parabolic rate law. The oxide scale mainly consisted of rutile and α-Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 phases. The results of the XPS analysis suggest that in rutile, Si exists as both Si〈sup〉4+〈/sup〉 ions and SiO〈sub〉2〈/sub〉. First-principles calculations indicated that Si〈sup〉4+〈/sup〉 ions stably dissolved into the interstitial sites in rutile, which suppresses oxygen migration through rutile by decreasing the number of oxygen vacancies, thereby inhibiting oxide scale formation. The reaction layer consisting of Ti〈sub〉3〈/sub〉Al and α″ phases on Ti-1mass% Si alloy suppressed the dissolution of oxygen into the substrate, i.e., α-case formation. The ratio of mass gain in α-case formation to total mass gain during oxidation at 1010 K and 1110 K ranged from 0.077 to 0.42. The addition of Si to the Ti-6Al-4V alloy was effective in improving both its oxidative resistance and tensile strength.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838818339653-fx1.jpg" width="292" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Joo Sung Kim, Young Been Kim, Seung Ki Baek, Young Dae Yun, Sung Hyeon Jung, Sung Woon Cho, Cheol Hyoun Ahn, Hyung Koun Cho〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To maximize the advantages of thin-film-based TiO〈sub〉2〈/sub〉 photoelectrodes for transparent self-driven photoelectrochemical (PEC) reactions, we artificially designed a compositionally graded bi-layer compounds consisting of SnO〈sub〉2〈/sub〉 and TiO〈sub〉2〈/sub〉. This structure exhibited a vigorous photocatalytic activity, sufficient photovoltage, and long-term stability. A compositionally graded SnO〈sub〉2〈/sub〉/TiO〈sub〉2〈/sub〉 interface (G-SnTiO) for improved charge transport efficiency and sufficient photovoltage was derived by a solution process using simultaneous sintering after sol-gel coating the SnO〈sub〉2〈/sub〉/TiO〈sub〉2〈/sub〉 layers; the structure was verified by various analysis methods, such as transmission electron microscopy, energy dispersive X-ray spectroscopy, and secondary ion mass spectrometry. The high performance from the G-SnTiO structure was attributed to an effective charge separation from the formation of a heterostructure interface with reduced defects, resulting in a sufficient photovoltage for self-driving. To construct self-driven and sustainable overall cells without an external potential and considerable reduction in transparency, two-electrode PEC cells with a G-SnTiO photoanode and Cu〈sub〉2〈/sub〉O photocathode were fabricated with a regular hexahedron shape for a color degradation test of methylene-blue-incorporated electrolytes, and exhibited enhanced purification speed and robust durability.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838818339379-fx1.jpg" width="335" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Usama Bin Humayoun, Seok Bin Kwon, Syed Kamran Sami, Dae-Ho Yoon〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Among various red phosphors, Mn〈sup〉4+〈/sup〉 activated fluoride hosts have received much attention due to their blue excitability and intense red emission. In this study we report a novel (NH〈sub〉4〈/sub〉)〈sub〉3〈/sub〉AlF〈sub〉6〈/sub〉:Mn〈sup〉4+〈/sup〉 phosphor, synthesized through a facile synthesis process avoiding high quantities of highly toxic HF acid. The synthesized host exhibit cubic structure in F-4 3m space group, with plenty of [AlF〈sub〉6〈/sub〉]〈sup〉3+〈/sup〉 octahedral sites. When activated with Mn〈sup〉4+〈/sup〉 the crystal structure is retained and the material exhibits characteristic excitation bands with maximum around 469 nm and intense red emission around 631 nm. Furthermore, the thermal gravimetric analysis revealed the stability of composition up to 250 °C. The phosphor however exhibits high sensitivity to increased temperature and showed sharp quenching of luminescence at elevated temperatures.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Rui Du, Du Yuan, Fei Li, Dongcheng Zhang, Shusen Wu, Shulin Lü〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This study intends to offer a depth understanding on controlling the morphology of eutectic Mg〈sub〉2〈/sub〉Si by adding in-situ TiB〈sub〉2〈/sub〉 particles into 10 〈em〉wt〈/em〉% Mg〈sub〉2〈/sub〉Si/Al composite. The evolution of the microstructure and mechanical properties of Mg〈sub〉2〈/sub〉Si/Al composites with different TiB〈sub〉2〈/sub〉 particles addition from 1 〈em〉wt〈/em〉% to 5 〈em〉wt〈/em〉% is investigated and the mechanism is also discussed. The results show that coarse eutectic Mg〈sub〉2〈/sub〉Si phase can be refined and modified with the addition of TiB〈sub〉2〈/sub〉 particles, and the lattice coherence between them is also confirmed. Besides, the addition of TiB〈sub〉2〈/sub〉 particles can greatly enhance multiple mechanical properties of composites at the same time. With 5% TiB〈sub〉2〈/sub〉 particles addition, the modulus, yield strength and elongation of composites are improved 11%, 59% and 141% respectively compared with Mg〈sub〉2〈/sub〉Si/Al composites. Moreover, different addition of TiB〈sub〉2〈/sub〉 particles changes gradually the fracture behavior of composites from brittle fracture to quasi-cleavage fracture, and finally to entirely ductile behavior.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 31 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): K. Dropiewski, A. Minns, M. Yakimov, V. Tokranov, P. Murat, S. Oktyabrsky〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Picosecond timing of energetic charged particles and photons is a challenge for many high-energy physics and medical applications. InAs Quantum Dots (QDs) embedded in GaAs matrix are expected to have singular scintillation properties. The advantages come from highly efficient energy conversion, as well as from fast electron capture and radiative recombination in QDs. We present design considerations and demonstration of an ultrafast, high photon yield room-temperature semiconductor scintillator. Due to the high refractive index of GaAs, the scintillator is fabricated in the form of a 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mn〉20〈/mn〉〈mspace width="1em"〉〈/mspace〉〈mi mathvariant="normal"〉μ〈/mi〉〈mi mathvariant="normal"〉m〈/mi〉〈/math〉 thick planar waveguide with an integrated InGaAs photodiode. QD luminescence of about 60% efficiency at room temperature has been shown, and modal attenuation stabilized at 1 cm〈sup〉−1〈/sup〉. Scintillation responses from 5.5 MeV alpha particles show an extremely fast decay time of 280 ps, a collection efficiency of 11% and a time resolution of 60 ps. This data confirms the unique potential properties of this scintillation detector.〈/p〉〈/div〉

Description: 〈p〉Publication date: 21 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 915〈/p〉 〈p〉Author(s): Jingyu Tang, Changdong Deng, Xi Wu, Shuai Li, Yuwen Wu, Wen Kang, Xiyin Zhang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper presents the design and prototyping of novel structure magnets–simplified multipole magnets, one octupole and one dodecapole. The field measurements of the prototypes show very good agreement with the numerical field calculations. The octupole prototype can produce either an anti-symmetric or a symmetric field distribution. Magnets with this novel structure can supply much higher saturation fields, e.g. doubled pole-gap strength of 0.6 T for the dodecapole prototype. The intrinsic field errors for the integrated field distribution are within 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si15.gif"〉〈mo〉±〈/mo〉〈/math〉1% for a rectangular shape of good field region, which are acceptable for some applications such as beam spot uniformization. Some key technical issues of building the magnets are also discussed. The success of the prototyping will pave the way for applications of the magnet family.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): Noriaki Kawaguchi, Go Okada, Kentaro Fukuda, Takayuki Yanagida〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We have tested high-temperature responses of prototype neutron detectors equipping Ce-doped lithium silicate glass (GS20), LiCaAlF〈sub〉6〈/sub〉:Ce, LiCaAlF〈sub〉6〈/sub〉:Eu, LiCaAlF〈sub〉6〈/sub〉:Ce, Na, and LiCaAlF〈sub〉6〈/sub〉:Eu, Na. These detectors were prepared by coupling of the scintillators to a photomultiplier tube (PMT) for high-temperature environments (R1288, Hamamatsu). In the pulse height spectra under thermal neutron irradiation in the temperature range from 25 °C to 150 °C, peak heights of all the samples decreased with increasing temperatures. The decreasing rates for the peak heights of LiCaAlF〈sub〉6〈/sub〉 scintillators were lower than that of GS20. The LiCaAl〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈msub〉〈mrow〉〈mi mathvariant="normal"〉F〈/mi〉〈/mrow〉〈mrow〉〈mn〉6〈/mn〉〈/mrow〉〈/msub〉〈/math〉scintillators can be used in the temperature range from 25 °C to 150 °C.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): A. Loi, A. Lai, G.F. Dalla Betta, R. Mendicino, S. Vecchi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The experimental conditions in future High Luminosity LHC experiments require new detector systems with increased performances compared to the current state of the art. In this context, increasing spacial resolution and including time measurement with a resolution of less than 50 ps for particle tracking systems can avoid false track reconstruction due to event pile up. For this kind of future tracking detectors the 3D silicon sensor technology appears as a good option. In this context the TIMESPOT initiative was launched. Concerning the development of the sensor, different geometrical solutions have been explored and simulated to optimize the timing response of the single pixel sensor using Sentaurus TCAD. The configuration with the best electric field characteristics for timing was selected for signal simulation. In order to compensate the very time-consuming behavior of TCAD simulations, a faster charge transport simulator with TCAD and Geant4 support is under development. Further sensor configurations, including a first primitive capacitive and resistive load, were also simulated and evaluated. This paper shows a general overview of the project with particular attention to the silicon sensor development. First results are presented.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 913〈/p〉 〈p〉Author(s): S. Mehdi Hashemi, Ali Negarestani〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, the performance of two GEM-type structures for the detection of alpha particle tracks in gaseous detectors based on SQS mode is presented. The operation of these structures was investigated in the presence of air, pure argon and P10 gas. By increasing the applied voltage to GEM-type plates beyond a certain value, each GEM-type’s through-hole individually entered to the SQS mode, when detector operated in the P10 gas. This mode was followed by the appearance of visible streamers in the space of holes exposed to alpha radiation. Two types of Thick Gas Electron Multipliers (TGEM) and Electron Multiplier Assemblies (EMA) with different geometries, as well as a cascade configuration of EMAs, were designed and constructed. Depending on the hole diameters in these structures, the location of the input beams can be determined optically with a specific resolution.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): G. Silvestre, on behalf of FOOT collaboration〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The goal of the FOOT (FragmentatiOn Of Target) experiment is to measure the fragmentation cross section of protons into H, C, O targets at beam energies of interest for hadrontherapy (50–250 MeV for protons and 50–400 MeV/u for Carbon ions) (Tommasino et al., 2015 [1]; FOOT CDR Conceptual Design, 0000 [2]). Given the short range of the fragments, an inverse kinematic approach has been chosen, hence requiring precise tracking capabilities for charged ions. One of the foreseen experiment subsystems will be the MSD (Microstrip Silicon Detector), composed of three 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mi〉x〈/mi〉〈/math〉–〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si2.gif"〉〈mi〉y〈/mi〉〈/math〉 measuring planes. In this work we evaluate the suitability of standard double-sided microstrip detectors, coupled to an high dynamic range readout chip, to be used for this task. The results about cluster signal, signal/noise, and dynamic range of readout chip are encouraging, and confirm the suitability of this class of sensors to be used in the FOOT experiment.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 919〈/p〉 〈p〉Author(s): Xiurong Li, Huihai He, Gang Xiao, Xiong Zuo, Shaohui Feng, Lingyu Wang, Cong Li, Mohsin Saeed, Zhen Cao, Xiangdong Sheng, Ning Cheng, for the LHAASO collaboration〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, novel methods are presented to measure the optical properties of the cylindrical water Cherenkov detector with high-reflectivity and diffuse reflection dominated Tyvek material as the inner surface. The mean transmission distance of photons between each reflection in the cylindrical water Cherenkov detector (the mean step length), is constant when there is a sufficient number of photons with random directions in the tank. The time distribution of the photons collected by the photomultiplier tube (PMT) in the water Cherenkov detector is approximately exponential, and the decay factor of the time distribution is determined by the absorption length of photons in the water, the reflectivity of the inner Tyvek surface, the mean step length of photons reflected in the tank, and the ratio of reflective Tyvek area to the total inner surface area. By considering the principles of photon propagation in the water Cherenkov detector, we developed novel methods to measure the water absorption length, Tyvek reflectivity, and mean step length of photons in the tank. The water absorption length and Tyvek reflectivity can be measured simultaneously by changing the height of the water, while the step length and Tyvek reflectivity in air can be measured simultaneously by changing the area of Tyvek, and the mean step length of photons can also be measured even all other parameters unknown. The proposed novel methods are supported by the deduction of formulae and verified by GEANT4 simulations and the prototype experiment.〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): S.S. Mani Prabu, H.C. Madhu, Chandra S. Perugu, K. Akash, R. Mithun, P. Ajay Kumar, Satish V. Kailas, Manivannan Anbarasu, I.A. Palani〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Welding of shape memory alloys without deterioration of shape memory effect could vastly extend their applications. To retain shape memory behavior, a solid-state welding technique called friction stir welding was employed in this study. Austenitic NiTi alloy sheets of thickness 1.2 mm were joined at tool rotational speeds of 800, 1000, and 1200 rpm. Due to dynamic recrystallization, the grain refinement has occurred in the weld region. The tensile testing has shown superelastic plateau for the welds at 800 and 1000 rpm. The phase transformation behavior of different weld regions was studied in detail using differential scanning calorimeter. A marginal drift in transformation temperatures was observed in the weld. To understand the drift in phase transformation temperatures, finite element analysis was carried out with focus on temperature distribution during welding. Finally, time-dependent shape recovery of a FSW welded joint was studied and it was found that the original position was completely recovered after 27 s at a temperature of 65 °C.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092583881833874X-fx1.jpg" width="437" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Matthias Stacher, Gabriel R. Reisinger, Klaus W. Richter〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Phase equilibria of Au-Ni-Si were investigated in the isothermal section at 700 °C using a combination of powder X-ray diffraction and quantitative phase analysis by SEM-EDX. Four vertical sections of the phase diagram at 10 at.% Au and at 15, 30 and 60 at.% Ni were studied by DTA. These data were combined with isothermal sections at 320° and 500° published earlier to develop a ternary reaction scheme and a liquidus surface projection. Fifteen ternary invariant reactions, a three-phase field maximum and a critical tie-line are proposed. The observed phase diagram is discussed regarding the possible use of Au-Si liquids for transient liquid phase (TLP) soldering of Nickel.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Yong Zhang, Jinming Guo, Jianghua Chen, Cuilan Wu, Karoline Sophie Kormout, Pradipta Ghosh, Zaoli Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Bulk nanocrystalline alloys usually possess enhanced properties than their coarse-grained counterparts. Here, first-principles calculations and aberration-corrected transmission electron microscope (TEM) were employed to investigate the atomic-scale deformation mechanism of Cu-based alloys. The effect of alloying element concentration and temperature-induced solute distribution on the unstable stacking fault energy (γ〈sub〉usf〈/sub〉), stable stacking fault energy (γ〈sub〉isf〈/sub〉) and unstable twin fault energy (γ〈sub〉utf〈/sub〉) were calculated using a Fermi–Dirac distribution of solutes for 42 binary Cu-X alloys. At medium temperature (〉200 K) or low solute concentrations (〈15 at.%), the stacking fault energies calculated from the Fermi–Dirac model accord well with the available experimental and theoretical results. The deformation mechanism was then evaluated by α = γ〈sub〉isf〈/sub〉/γ〈sub〉usf〈/sub〉 and β = γ〈sub〉utf〈/sub〉/γ〈sub〉usf〈/sub〉, smaller α (β) favors an easier formability of extended dislocations (twins). Most subgroup VI-VIII metals in the periodic table can slightly increase the γ〈sub〉usf〈/sub〉, γ〈sub〉isf〈/sub〉 and γ〈sub〉utf〈/sub〉 of Cu, and have almost no influence on α and β. While main group and subgroup II-V elements can decrease γ〈sub〉usf〈/sub〉, γ〈sub〉isf〈/sub〉 and γ〈sub〉utf〈/sub〉 as well as the values of α and β. For alloying elements of Pd, Ag, Pt and Au, the values of α and β increase, suggesting a tendency of deformation mechanism from extended dislocations to full dislocations. Furthermore, high-resolution TEM (HRTEM) images of four representative nanocrystalline alloys (pure Cu, Cu-Fe, Cu-Ag and Cu-Zn) corroborates the prodiction with α and β as well as the empirical twinnability. The α and β remain almost the same as that of pure Cu when alloyed with Fe while they decrease with Zn, and the extended dislocations and twins were commonly observed for Cu, Cu-Fe and Cu-Zn. The α and β increased with Ag addition although the γ〈sub〉isf〈/sub〉 decreased, and the extended dislocations were barely observed for Cu-Ag sample. The theoretical and microstructural correlation provides insights into the deformation mechanism of Cu-based alloys.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Yongju Yoo, Yun Chan Kang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nb〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 materials based on intercalation reactions have been extensively studied as anode materials for lithium-ion batteries. Mesoporous Nb〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 microspheres with narrow size distribution are the ideal structure for achieving a high volumetric capacity. Mesoporous filled- and yolk-shell-structured (reported for the first time) Nb〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 microspheres are synthesized using a highly porous carbon template. The NbSe〈sub〉3〈/sub〉-C composite transforms into yolk-shell-structured Nb〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 microspheres by a one-step oxidation process. The filled microspheres having ultrafine crystallite size and high mesopore volume show better cycling and rate performances than the yolk shell microspheres. The discharge capacity of the filled microspheres at a current density of 1 A g〈sup〉−1〈/sup〉 is 124 mA h g〈sup〉−1〈/sup〉 in the 5000〈sup〉th〈/sup〉 cycle, and the capacity retention in the second cycle is 76%. The discharge capacity of the filled microspheres decreases by approximately 26% from 171 mA h g〈sup〉−1〈/sup〉 to 127 mA h g〈sup〉−1〈/sup〉 when the current density increases from 0.5 A g〈sup〉−1〈/sup〉 to 10 A g〈sup〉−1〈/sup〉. Particularly, the volumetric capacity of the filled microspheres at a high current density of 10 A g〈sup〉−1〈/sup〉 is 2.3 times higher than that of the yolk-shell-structured microspheres (filled ≈ 11.5 mA h cc〈sup〉−1〈/sup〉 vs. yolk ≈4.9 mA h cc〈sup〉−1〈/sup〉).〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Dunya M. Babanly, Ziya S. Aliev, Qorkhmaz M. Huseynov, Salim M. Asadov, Solmaz N. Mustafaeva, Dilgam B. Tagiyev〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The phase equilibria in the ternary Tl-S-I system were investigated experimentally by means of powder X-ray diffraction (PXRD) and differential thermal analysis (DTA). Five isopleth sections, liquidus surface projection and room temperature isothermal section were constructed based on experimental data. 〈em〉dc〈/em〉-and 〈em〉ac〈/em〉-electric properties of the TlS and Tl〈sub〉6〈/sub〉SI〈sub〉4〈/sub〉 crystals were studied within the temperature and frequency ranges from 120 K to 300 K and from 50 kHz to 35 MHz, respectively. The hopping mechanism for charge transfer over the localized states near the Fermi level was established at low temperatures and high frequencies for these compounds. The density and energy scatter of the states which are located in the vicinity of the Fermi level as well as the average time and distances of jumps were estimated for the title compounds.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Marietta Seifert, Gayatri K. Rane, Siegfried B. Menzel, Steffen Oswald, Thomas Gemming〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A sufficient oxidation resistance of RuAl thin films is crucial for their application in high temperature sensors e.g. based on the surface acoustic waves principle. To improve the high temperature stability, an Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 or SiO〈sub〉2〈/sub〉 cover layer is added to protect the films from oxidation especially for application in air. The covered RuAl films are annealed at temperatures up to 900 °C under high vacuum and in air for 10 h. X-ray diffraction, cross section imaging and Auger electron spectroscopy are applied to reveal the suitability of the cover layers as oxidation barrier. While there is hardly any difference between the samples with or without cover layer after annealing under high vacuum, only the samples with SiO〈sub〉2〈/sub〉 cover are stable up to 800 °C in air.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838818339525-fx1.jpg" width="483" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): O.V. Maksakova, S. Simoẽs, A.D. Pogrebnjak, O.V. Bondar, Ya.O. Kravchenko, T.N. Koltunowicz, Zh.K. Shaimardanov〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Multilayered ZrN/CrN coatings were produced by the cathodic arc physical vapor deposition (CA-PVD). Morphology, element distribution, structural and thermal properties were investigated. Microhardness and nanoindentation tests were conducted to study the mechanical properties of the coatings. The experimental results of scanning electron microscopy (SEM) revealed the cellular microrelief of the surface and well-defined multilayered architecture of the coatings. Energy dispersive spectroscopy (EDS) provided the chemical characterization of the coatings and revealed the formation of stoichiometric composition in coatings. X-ray diffraction (XRD) studies showed that (200) and (111) plane reflections of ZrN and Cr〈sub〉2〈/sub〉N phases, correspondingly, were with maximum intensity. Transmission electron microscopy (TEM) analysis revealed that the films comprise of nanometric equiaxed grains with average sizes from 12.8 to 15.1 nm for ZrN layers and from 14.5 to 28.1 nm for CrN layers. The high-temperature heat treatment caused exothermic and endothermic reactions, which were mainly attributed to the improvements or disordering of the coatings' structure, consequently. The highest values of microhardness (4966HV0.025) and nanohardness (24.58 GPa) were obtained for the sample with a bilayer thickness of 732 nm, the average crystallite size of 13.3 nm and nitrogen content of 49 at%. Experimental results indicated that deposited composites can be effectively used in the production of industrial tools, implements for cutting etc.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Manisha Kumari, Shrabani Mondal, Prashant K. Sharma〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The drug loading and release properties of Eu〈sup〉3+〈/sup〉 doped GdPO〈sub〉4〈/sub〉 nanoparticles (NPs) were studied using a simple electrochemical protocol in an 〈em〉in-vitro〈/em〉 environment, taking acetaminophen as a model drug. The electrochemical monitoring of drug release was also validated with absorption spectroscopy technique. For this purpose, dual stimuli (pH and temperature) responsive monoclinic mesoporous GdPO〈sub〉4〈/sub〉 nanoparticles of size ∼22 nm were synthesized by a simple hydrothermal method. Crystal structure, size, shape, morphology, porosity, optical property and magnetic properties of the obtained product were studied by different characterization techniques. Successful loading of drug in NPs was investigated by Fourier transform infrared spectroscopy (FT-IR). Photoluminescence (PL) measurement shows orange-red color emission corresponding to 〈sup〉5〈/sup〉D〈sub〉0〈/sub〉→〈sup〉7〈/sup〉F〈sub〉2〈/sub〉 transitions of Eu〈sup〉3+〈/sup〉 ions. The vibrating sample magnetometer (VSM) measurements showed negligible hysteresis in both samples, suggesting retention of the superparamagnetic behavior of GdPO〈sub〉4〈/sub〉 NPs. The high loading capacity of 79% and encapsulation efficiency of 83% is observed when acetaminophen, an anti-fever drug, was loaded on these mesoporous GdPO〈sub〉4〈/sub〉 NPs. The drug was attached on NPs surfaces via absorption, without any special surface modification. During drug release studies, a spontaneous and smooth release from these mesoporous NPs was observed at a moderate-high temperature (37 °C) and low pH (pH 5) with no sign of burst release. These nanoparticles were capable of targeting and specific release of the loaded drug in response to pH and temperature and hence may serve as a potential drug carrier for 〈em〉in-vivo〈/em〉 applications.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838818339604-fx1.jpg" width="275" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Shixiang Zuo, Zhan Liu, Wenjie Liu, Xiazhang Li, Zhongyu Li, Chao Yao, Qun Chen, Yongsheng Fu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Oriented rutile TiO〈sub〉2〈/sub〉 nanorod arrays (TiO〈sub〉2〈/sub〉 NRA) were elaborately grown on the conductive mica (C-mica) with Sb-SnO〈sub〉2〈/sub〉 seed crystal by a hydrothermal strategy to achieve TiO〈sub〉2〈/sub〉 NRA/C-mica composites. The as-obtained samples were characterized by X-ray diffraction, field emission scanning electron microscope, X-ray photoelectron spectroscopy, UV–vis diffuse reflectance spectroscopy and photo-electrochemical measurements. Compared with TiO〈sub〉2〈/sub〉 NP/mica, TiO〈sub〉2〈/sub〉 NRA/C-mica coated film exhibits more excellent physical barrier ability in the dark, and an enhanced photo-induced current density as well as a more negative photo-potential shift in the light, indicating remarkable photo-cathodic protection for 304 stainless steel (304SS). The distinctive 1D-2D architecture of TiO〈sub〉2〈/sub〉 NRA/C-mica facilitates the transmission and separation of photo-induced electron-hole pairs. Furthermore, it's the first time that the TiO〈sub〉2〈/sub〉 NRA/C-mica hybrid film is found to possess continuous and stable cathodic protection for the 304SS over a long period in the dark.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092583881834009X-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Baochen Wang, Ziyao Wang, Yangai Liu, Tao Yang, Zhaohui Huang, Minghao Fang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Crystal structure tailoring is a commonly used method for tuning the luminescence of phosphors. This study mainly aims at luminescent spectra tuning of Sr〈sub〉1−〈em〉x〈/em〉〈/sub〉Ba〈sub〉〈em〉x〈/em〉〈/sub〉Al〈sub〉2〈/sub〉Si〈sub〉2〈/sub〉O〈sub〉8〈/sub〉:Eu〈sup〉2+〈/sup〉 phosphors by substitution of Ba for Sr ions. The phase composition was characterized by X-ray powder diffraction and the crystal structure was determined by using the Rietveld refinement method. The excitation and emission spectra, diffuse reflectance spectra, and thermal quenching were also investigated in detail. The results show that Sr〈sub〉1−〈em〉x〈/em〉〈/sub〉Ba〈sub〉〈em〉x〈/em〉〈/sub〉Al〈sub〉2〈/sub〉Si〈sub〉2〈/sub〉O〈sub〉8〈/sub〉:Eu〈sup〉2+〈/sup〉 phosphors can form a series of continuous solid solutions in the range from 0 to 0.75. With the increase in 〈em〉x〈/em〉 value, the emission spectra show an obvious redshift from 415 to 450 nm. The emission redshift plays an important role in enabling Sr〈sub〉1−〈em〉x〈/em〉〈/sub〉Ba〈sub〉〈em〉x〈/em〉〈/sub〉Al〈sub〉2〈/sub〉Si〈sub〉2〈/sub〉O〈sub〉8〈/sub〉:Eu〈sup〉2+〈/sup〉 to be used as a standard blue phosphor for application in white-light-emitting diodes.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838818340465-fx1.jpg" width="303" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Jia Sun, Qian-Gang Fu, Tao Li, Guang-Peng Zhang, Rui-Mei Yuan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Constituent phases, porosity and residual stress are significant factors influencing the performance of two-dimension (2D) structural components. In present study, these factors with respect to thermally sprayed MoSi〈sub〉2〈/sub〉 based composite were elaborately adjusted through plasma spraying power to investigate the oxidation behavior in medium temperature range of 400–900 °C. By increasing the operation powers, the improved melting degree of feedstock led to the increased metastable phases and the decreased porosity in the MoSi〈sub〉2〈/sub〉 based composite but it did not remarkably affect the residual stress distribution. After the analysis on the medium-temperature oxidation, it can be concluded that the metastable phases and the porosity were principally responsible for the enhanced oxidation resistance of the MoSi〈sub〉2〈/sub〉 based composite. The thermal-sprayed 2D MoSi〈sub〉2〈/sub〉 based composites with large amounts of 〈em〉β〈/em〉 phases and low porosity can achieve the outstanding oxidation resistance in medium temperature range.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Li Jin, Jun Qiao, Lei Hou, Liang Wang, Lin Zhang, Xu Lu, Hongliang Du, Xiaoyong Wei, Yan Yan, Gang Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Perovskite ferroelectric ceramics with 〈em〉T〈/em〉〈sub〉〈em〉m〈/em〉〈/sub〉 (temperature corresponding to maximum dielectric permittivity 〈em〉ε〈/em〉′) around room temperature and high electrostrictive coefficient 〈em〉Q〈/em〉〈sub〉33〈/sub〉 are of interest to the applications in high-precision actuators, since low-hysteresis/non-hysteresis and high strain response can be generated in these materials based on a purely electrostrictive effect. In this work, undoped Ba(Zr〈sub〉0.2〈/sub〉Ti〈sub〉0.8〈/sub〉)O〈sub〉3〈/sub〉 (BZT) and La〈sup〉3+〈/sup〉-doped Ba(Zr〈sub〉0.2〈/sub〉Ti〈sub〉0.8〈/sub〉)O〈sub〉3〈/sub〉 (BLZT) lead-free ferroelectrics were synthesized by solid state reaction method. Their dielectric and ferroelectric properties were investigated systematically with an emphasis on electrostrictive effect. With respect to increase of La〈sup〉3+〈/sup〉 content from 0 to 1%, the 〈em〉T〈/em〉〈sub〉〈em〉m〈/em〉〈/sub〉 of BLZT decreases from 44.5 °C to 14.6 °C, and the diffuseness degree 〈em〉γ〈/em〉 increases from 1.814 to 1.993. A conductive mechanism, which is prominent in undoped BZT, is inhibited drastically by introducing the La〈sup〉3+〈/sup〉 into BZT. A high electrostrictive strain of 0.08% and a low hysteresis 〈em〉η〈/em〉 (〈10%) are obtained simultaneously in 〈em〉x〈/em〉 = 0.25% composition at room temperature. The 〈em〉Q〈/em〉〈sub〉33〈/sub〉 ranges from 0.0377 m〈sup〉4〈/sup〉/C〈sup〉2〈/sup〉 and 0.0537 m〈sup〉4〈/sup〉/C〈sup〉2〈/sup〉. This work not only reports a high electrostrictive effect in BLZT ferroelectrics, but also provides BLZT ceramics with a potential application in high-precision actuators.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Fuwen Yu, Chunjin Hang, Menghui Zhao, Hongtao Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A die-attach material based on an Sn-coated Ni core-shell powder with a high re-melting temperature can be used for high-temperature applications. The outer Sn layers of the Sn-coated Ni particles possess a low melting point of 232 °C and can be completely converted into a Ni〈sub〉3〈/sub〉Sn〈sub〉4〈/sub〉 intermetallic compound with a high re-melting point of 794.5 °C after reflowing at a low temperature of 250 °C for 40 min. This die-attach material exhibits an excellent high-temperature operational capability, with a high shear strength of 40.2 MPa at 500 °C. The coefficient of thermal expansion (CTE) of the reflowed preform is between those of SiC and Cu, which is highly beneficial for mitigating the stress caused by the CTE mismatch between these materials. In addition, the thermal conductivity of the bondline is sufficiently high for heat dissipation during operation.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): José C.S. Filho, Sérgio C. Zilio, Djalmir N. Messias, Viviane Pilla, Anielle C.A. Silva, Noelio O. Dantas, Acácio A. Andrade〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The thermal expansion (〈em〉α〈/em〉) and the thermo-optic (d〈em〉n〈/em〉/dT) coefficients of a phosphate glass dubbed as PANK were simultaneously measured using a single arm double interferometer from 100 to 400 K of the temperature range. An athermal behavior of the optical path difference in a two-beam interferometer was found around 200 K. This result is in agreement with a similar observation carried out applying the Thermal Lens spectrometry (TLS) of Nd-doped PANK glass at ∼180 K. The main difference between these temperature values is ascribed to the sample surface curvature induced by the laser beam in thermal lens measurements. The athermal behavior shows that this glass has the potential for laser applications as an ion host at low temperature, and small changes in the glass composition should be explored to bring this property to room temperature.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838818339306-fx1.jpg" width="288" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): B.N. Sahoo, S.K. Panigrahi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Magnesium matrix in-situ composites with hybrid TiC+TiB〈sub〉2〈/sub〉 reinforcement are potential materials for automobile and aerospace applications. It is essential to establish the processing map of such composites as these materials may undergo several thermo-mechanical processes while manufacturing engineering components. In the current work, AZ91 Magnesium matrix TiC+TiB〈sub〉2〈/sub〉 reinforces hybrid in-situ along with its base counterpart were developed and subjected to solutionization followed by peak aging treatment. The safe processing zone for both base and in-situ composite at all heat treatment conditions have been established through processing map based on dynamic materials model (DMM) by conducting hot compression tests at various temperatures (250 °C – 450 °C) and strain rates (0.001 s〈sup〉−1〈/sup〉 – 10 s〈sup〉−1〈/sup〉). Two regions: stable and instable were identified from processing map for all the material conditions. Dynamic recrystallization is the main dominant mechanism in stable region, whereas instable region is characterized by twin and intergranular cracks. To understand the mechanism of hot deformation behavior, activation energy is calculated based on constitutive model for all material conditions. The developed in-situ composite in peak aged condition is found to possess higher activation energy (∼230 kJ/mol) as compared to base alloy (∼126 kJ/mol). A correlation between constitutive model and processing map have been established with an emphasis on their microstructures.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838818339483-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Catalysis Today〈/p〉 〈p〉Author(s): Pierre Pichat〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Studies of the adsorption and reactions of appropriate molecules are a valuable means to probe active surfaces. This overview deals with the use of nitrogen monoxide – a molecule that has less been utilized than some others as a surface probe – to investigate TiO〈sub〉2〈/sub〉 and TiO〈sub〉2〈/sub〉-containing materials, with or without photo-excitation. It shows that diverse information can be derived from: (1) the infrared spectra of adsorbed NO; (2) the isotopic exchange of N〈sup〉18〈/sup〉O; (3) the formation of N〈sub〉2〈/sub〉O and N〈sub〉2〈/sub〉; (4) the use of NO (or N〈sup〉18〈/sup〉O) in oxidation reactions in place of O〈sub〉2〈/sub〉; and (5) the evaluation of the electron transfer to NO through density functional theory calculations, ultraviolet photoemission spectroscopy, and photoconductance measurements. Valuable knowledge may thus be potentially acquired on: the accessibility and reactivity of surface OH groups, the lability of surface O atoms, the self-cleaning efficacy, the environment and dispersion of TiO〈sub〉2〈/sub〉 in composite materials, the existence of bandgap electronic states, and the electron transfer capacity, depending on the investigation technique employed, the conditions and the type of TiO〈sub〉2〈/sub〉 sample.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0920586118311921-ga1.jpg" width="348" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 30 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Catalysis Today〈/p〉 〈p〉Author(s): G. Bonura, A.A. Khassin, T.M. Yurieva, C. Cannilla, F. Frusteri, L. Frusteri〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A series of coprecipitated binary Cu-ZrO〈sub〉2〈/sub〉 catalysts was found to show an interesting activity–selectivity pattern during methanol synthesis from catalytic hydrogenation of carbon oxides (〈em〉P〈/em〉〈sub〉R〈/sub〉, 20–30 atm; 〈em〉T〈/em〉〈sub〉R〈/sub〉, 200–240 °C). The effects of various pre–treatments as well as the copper/zirconia ratio on the structural and chemical properties of these samples were examined. The isoconversional Ozawa-Flynn-Wall method was applied to study the reduction behaviour, while the best fit modelling was used to establish the plausible mechanism of copper reduction. The extent of methanol formation rate was found to be dependent on the structure formed upon catalyst reduction, both in CO and in CO〈sub〉2〈/sub〉 hydrogenation conditions. The pre–calcination of the sample at a temperature as high as 650 °C negatively affected the methanol formation rate under CO hydrogenation conditions, while under the same activation treatment an increased specific activity was observed in CO〈sub〉2〈/sub〉 hydrogenation conditions, although with a minor methanol selectivity, since the rate of the WGS reaction was stronger enhanced. The incorporation of Zn into the catalyst formulation resulted in a visible increasing of the methanol formation rate, owing to the formation of a copper–zinc mixed oxide during calcination, which leads to higher metal dispersion also depressing the methane formation rate.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0920586118307028-ga1.jpg" width="286" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 15 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): N. Cartiglia, R. Arcidiacono, M. Ferrero, M. Mandurrino, H.-F.W. Sadrozinski, V. Sola, A. Staiano, A. Seiden〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The combination of precision space and time information in particle tracking, the so called 4D tracking, is being considered in the upgrade of the ATLAS, CMS and LHCb experiments at the High-Luminosity LHC, set to start data taking in 2024-25. Regardless of the type of solution chosen, space–time tracking brings benefits to the performance of the detectors by reducing the background and sharpening the resolution; it improves tracking performances and simplifies tracks combinatorics. Space–time tracking also allows investigating new physics channels, for example it opens up the possibilities of new searches in long-living particles by measuring accurately the time of flight between the production and the decay vertexes. The foreseen applications of 4D tracking in experiments with very high acquisition rates, for example at HL-LHC, add one more dimension to the problem, increasing dramatically the complexity of the read-out system and that of the whole detector design: we call 5D tracking the application of 4D tracking in high rate environments.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 913〈/p〉 〈p〉Author(s): George Kitis, Vasilis Pagonis〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Experimental Thermoluminescence (TL) glow curves for most dosimetric materials are composites, consisting of weakly or strongly overlapping peaks. The ability to discriminate between two overlapping peaks defines the resolution of a TL glow curve. Although the concept of resolution has been defined and used widely in many areas of science, there have been no previous attempts to define and study the resolution of overlapping TL peaks. In this work the resolution parameter R is defined in terms of the geometrical characteristics of TL peaks. A large number of TL glow curves consisting of two peaks were numerically evaluated for various degrees of overlapping between them. These numerically generated glow curves were analyzed by a computerized glow curve deconvolution analysis, in order to determine the reliability of the deconvolution results as a function of the resolution parameter R.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 910〈/p〉 〈p〉Author(s): S. Zhao, G. Lioliou, S. Butera, M.D.C. Whitaker, A.M. Barnett〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A Commercial-Off-The-Shelf (COTS) 4H-SiC p-n photodiode (sold as a UV detector) was investigated as detector of electrons (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si34.gif"〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉β〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈/mrow〉〈/msup〉〈/math〉 particles) over the temperature range 100 °C to 20 °C. The photodiode had an active area of 0.06 mm〈sup〉2〈/sup〉. The currents of the photodiode were measured in dark condition and under the illumination of a 〈sup〉63〈/sup〉Ni radioisotope 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si34.gif"〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉β〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈/mrow〉〈/msup〉〈/math〉 particle source (endpoint energy = 66 keV). The photodiode was then coupled to a custom-made low-noise charge-sensitive preamplifier to make a direct detection particle counting electron spectrometer. 〈sup〉63〈/sup〉Ni 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si34.gif"〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉β〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈/mrow〉〈/msup〉〈/math〉 particle spectra were accumulated with the spectrometer operating at temperatures up to 100 °C. The quantum efficiency of the photodiode as well as the spectrum expected to be detected were calculated via Monte Carlo simulations produced using the CASINO computer program. Comparisons between the simulated and detected 〈sup〉63〈/sup〉Ni 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si34.gif"〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉β〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈/mrow〉〈/msup〉〈/math〉 particle spectra are presented. The work was motivated by efforts to apply COTS technologies to develop low-cost space science instrumentation; a low-cost electron spectrometer of this type could be included on a university-led CubeSat mission for space plasma physics and magnetosphere experiments.〈/p〉〈/div〉

Description: 〈p〉Publication date: 11 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 911〈/p〉 〈p〉Author(s): M. Sharma, J. Nattress, I. Jovanovic〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Design of deuterium–tritium (DT) neutron generator facilities requires a careful assessment of radiation shielding. In the models of such facilities an isotropic distribution of neutron flux produced by the neutron generator is usually assumed. However, prior studies have shown that neutron flux surrounding the neutron generator can be anisotropic. This anisotropy results mostly from the design of the generator tube, as well as the angular dependence of DT fusion reaction cross section. In this work, the angular neutron flux was measured for a standard commercially available DT generator (Thermo Fisher Scientific, Model P211) using an organic scintillator and a significant degree of anisotropy was confirmed to exist. The experimentally determined flux was then used in Monte Carlo simulations to examine the impact of anisotropy on the effectiveness of radiation shielding. Although the shielding effectiveness is not considerably affected by the anisotropy, the dose rates in air around the unshielded generator can be significantly different from those predicted when an assumption of isotropic flux is made. These considerations need to be included in modeling of the dose rate around the generator in neutron generator facilities that employ typical neutron generators, which exhibit some degree of anisotropy in neutron flux.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 910〈/p〉 〈p〉Author(s): David Longuevergne〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The different processes at the origin of the dependence of the surface resistance with the RF magnetic field are still not fully understood. Several models have emerged since many years to explain the drop of the quality factor 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si96.gif"〉〈msub〉〈mrow〉〈mi〉Q〈/mi〉〈/mrow〉〈mrow〉〈mn〉0〈/mn〉〈/mrow〉〈/msub〉〈/math〉 (commonly called Q-drop) of a superconducting cavity versus the accelerating gradient. Experimental data are commonly fitted by applying a coarse approximation to convert the 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si96.gif"〉〈msub〉〈mrow〉〈mi〉Q〈/mi〉〈/mrow〉〈mrow〉〈mn〉0〈/mn〉〈/mrow〉〈/msub〉〈/math〉 (a global property) into a surface resistance (local property). Extracting accurately the surface resistance from experimental data requires to take into account the RF field distribution over the accelerating structure contrary to what is commonly done in the community. Assuming a field dependent surface resistance does not allow anymore to use the well-known formula 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si3.gif"〉〈msub〉〈mrow〉〈mi〉Q〈/mi〉〈/mrow〉〈mrow〉〈mn〉0〈/mn〉〈/mrow〉〈/msub〉〈mo〉=〈/mo〉〈mi〉G〈/mi〉〈mo〉∕〈/mo〉〈mi〉R〈/mi〉〈/math〉〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si4.gif"〉〈msub〉〈mrow〉〈/mrow〉〈mrow〉〈mi mathvariant="normal"〉s〈/mi〉〈/mrow〉〈/msub〉〈/math〉. This paper gives a procedure to perform an accurate conversion of the quality factor measured during a cavity test into a surface resistance to avoid any error in the evaluation of fitting parameters due to the geometry.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 15 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): S. Roy, S. Rudra, S. Shaw, S. Chatterjee, S. Chakraborty, R.P. Adak, S. Biswas, S. Das, S.K. Ghosh, S.K. Prasad, S. Raha〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Study of the stability of gain and energy resolution for a triple GEM detector has been performed under continuous radiation of X-ray with high rate, using premixed gas of Argon and CO〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈msub〉〈mrow〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msub〉〈/math〉 in 70/30 ratio and conventional NIM electronics. A strong 〈sup〉55〈/sup〉Fe X-ray source is used for this study. The novelty of this study is that for the stability test same source is used to irradiate the GEM chamber and to monitor the spectrum. The radiation is not collimated to a point but exposed to a larger area. Effect of temperature and pressure on these parameters are also studied. The detail method of measurement and the first test results are presented.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 910〈/p〉 〈p〉Author(s): T. Washimi, M. Kimura, M. Tanaka, K. Yorita〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A two-phase argon detector has high discrimination power between electron recoil and nuclear recoil events based on the pulse shape discrimination and the ionization/scintillation ratio (S2/S1). This character is very suitable for the dark matter search to establish the low background experiment. However, the basic properties of S2/S1 of argon are not well known, as compared with xenon. We report the evaluation of S2/S1 properties with a two-phase detector at drift-fields of 0.2–3.0 kV/cm. Finally, the discrimination power against electron recoil background of S2/S1 is discussed.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 910〈/p〉 〈p〉Author(s): A. Natochii, L. Burmistrov, F. Addesa, O. Bezshyyko, D. Breton, V. Chaumat, G. Cavoto, S. Dubos, Y. Gavrikov, F. Iacoangeli, J. Maalmi Di Bello, S. Montesano, V. Puill, R. Rossi, W. Scandale, A. Stocchi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A method to characterise the quality of a fused silica surface using a 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si4.gif"〉〈mi〉β〈/mi〉〈/math〉-source is presented. Two fused silica bars (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si2.gif"〉〈mn〉5〈/mn〉〈mo〉×〈/mo〉〈mn〉10〈/mn〉〈mo〉×〈/mo〉〈mn〉400〈/mn〉〈mspace width="1em"〉〈/mspace〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉mm〈/mi〉〈/mrow〉〈mrow〉〈mn〉3〈/mn〉〈/mrow〉〈/msup〉〈/math〉) were fabricated for the Cherenkov detector for proton Flux Measurement installed at vacuum chamber of the Super Proton Synchrotron at CERN. The resolution of such device is defined by the collection efficiency of the Cherenkov light, which is produced by relativistic charged particles in the fused silica. Thus, the surface quality of the radiator should be as good as possible to avoid light losses. The method is based on the scanning of the radiator surface with a 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si3.gif"〉〈msup〉〈mrow〉〈/mrow〉〈mrow〉〈mn〉90〈/mn〉〈/mrow〉〈/msup〉〈mi〉S〈/mi〉〈mi〉r〈/mi〉〈/math〉 radioactive source and measurements of the Cherenkov light rate, detected by a PMT attached to the quartz bars. The data have been compared with a Monte-Carlo simulation, providing an estimation of the radiator’s probability of the total internal reflection and inefficient area at the edges of the bars.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 15 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): M. Usami, G. Boca, P.W. Cattaneo, M. De Gerone, F. Gatti, M. Nakao, M. Nishimura, W. Ootani, M. Rossella, Y. Uchiyama〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We studied the impact of radiation damage on scintillation counters read out by six SiPMs connected in series focusing on their time resolution. Six SiPMs from AdvanSiD were irradiated step by step with a 37 MBq 〈sup〉90〈/sup〉Sr source. At the integrated dose expected at the end of the MEG II experiment, the time resolution at 30 °C was measured to be worse by 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si29.gif"〉〈mo〉∼〈/mo〉〈/math〉29%. However, the deterioration is found to be reduced to 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si29.gif"〉〈mo〉∼〈/mo〉〈/math〉6% at 10 °C since thermal dark noise is suppressed. We also tested the effect of connecting in series differently damaged SiPMs. We observed a position dependence of the time center in a counter, which worsened the time resolution.〈/p〉〈/div〉

Description: 〈p〉Publication date: 11 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 911〈/p〉 〈p〉Author(s): Haeryong Yang, Gyujin Kim, Heung-Sik Kang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The hard X-ray free electron laser at the Pohang Accelerator Laboratory (PAL-XFEL) in the Republic of Korea achieved a saturation of free electron laser (FEL) beam at 14.5 keV with an unprecedented intensity of 2.8E+11 photons per pulse. Successfully maintaining a very small emittance electron beam along the 700-m long linac, maximizing the spectral overlap of undulator radiation along the undulator line by the undulator radiation spectrum analysis, and optimal matching between the electron beam and photon beam through the 100-m long undulator line have allowed saturation and reliable operation of a 14.5 keV FEL beam.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 15 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): F. Abudinen, K. Ackermann, P. Ahlburg, M. Albalawi, O. Alonso, L. Andricek, R. Ayad, V. Babu, Y. Bai, T. Bilka, R. Blanco, M. Boronat, A. Bozek, C. Camien, A. Caldwell, V. Chekelian, B. Deschamps, A. Dieguez, J. Dingfelder, Z. Doležal〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Belle II experiment will run with a reduced beam asymmetry and a factor of 40 higher instantaneous luminosity compared to the Belle experiment. To cope with this and to be able to perform high precision vertex measurements for charge conjugation parity violating processes, a pixel detector based on DEPFET technology will be installed in the center of Belle II. Its basic properties and the DAQ chain are presented in this article.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 910〈/p〉 〈p〉Author(s): Zdzisław Dębicki, Karol Jędrzejczak, Jacek Karczmarczyk, Marcin Kasztelan, Ryszard Lewandowski, Jerzy Orzechowski, Jacek Szabelski, Maria Szeptycka, Przemysław Tokarski〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉We performed measurements of thermal and non-thermal neutron flux in underground laboratories in Gran Sasso, Italy and in Slanic Prahova, Romania. The measurements were made with a set of helium counters: bare for thermal neutrons and covered by blocks of moderator for higher energy neutrons. We found that thermal neutron flux in Slanic is four times smaller than in Gran Sasso, probably due to lack of alpha-radioactive sources in the surrounding rocks. In contrast, the flux of higher energy neutrons in Slanic proved to be 1.4 times higher than in Gran Sasso, which can be explained by higher cosmic muon flux in Slanic.〈/p〉 〈p〉Our result for thermal neutron flux is lower than results of most of the previous measurements carried out in LNGS laboratory but thanks to a different method of analysis the reliability of our results is very high. The result for higher energy neutrons agrees with average energy spectrum resulting from previous measurements.〈/p〉 〈p〉Our measurements in Slanic were the first ones ever performed in this laboratory, and can be used as a reference by future experiments.〈/p〉 〈/div〉

Description: 〈p〉Publication date: 11 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 911〈/p〉 〈p〉Author(s): Graeme Turkington, Kelum A.A. Gamage, James Graham〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Strontium-90 is one of the primary beta-emitting radionuclides found at nuclear decommissioning sites. Monitoring its activity in the environment is of utmost importance given its radiotoxicity. Current procedures for the beta detection of strontium-90 are time consuming, produce secondary waste and expensive. There is a demand for real-time in situ radiostrontium monitoring in groundwater at nuclear decommissioning sites. This paper presents a review of existing techniques for strontium-90 monitoring and examines a novel approach through direct beta detection with a gallium arsenide photodiode based detector. A proof of concept detector was modelled in the physics simulation software, Geant4, and evaluated as candidate for in situ detection of beta emitting radionuclides. The simulation results indicate that the detector is physically capable of counting 89.86% of incident 0.546 MeV electrons from a 1 mm range in water. This validation will provide the basis for further development of an in situ beta detector.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 15 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): A. Di Mauro, on behalf of the ALICE Collaboration〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉ALICE, the CERN LHC experiment devoted to the study of the QGP (Quark-Gluon Plasma) properties, will undergo a comprehensive upgrade during the second long shutdown of the LHC (in 2019-2020) to enhance the capability for high precision measurements of rare processes at low transverse momenta (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈msub〉〈mrow〉〈mi〉p〈/mi〉〈/mrow〉〈mrow〉〈mi〉T〈/mi〉〈/mrow〉〈/msub〉〈/math〉). One of the key elements of the upgrade strategy is the novel, high-resolution, ultra-light Inner Tracking System (ITS) consisting of seven concentric layers of Monolithic Active Pixel Sensors (MAPS) covering a total active area of 10 m〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si42.gif"〉〈msup〉〈mrow〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msup〉〈/math〉 segmented in 12.5 Gpixels. This paper presents an overview of the detector components, the most relevant characterisation results and the status of the detector construction.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 15 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): N. Karpushkin, D. Finogeev, M. Golubeva, F. Guber, A. Ivashkin, A. Izvestnyy, V. Ladygin, S. Morozov, A. Kugler, V. Mikhaylov, A. Senger〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Compressed Baryonic Matter (CBM) experiment at the future Facility for Antiproton and Ion Research (FAIR) is aimed to explore the QCD phase diagram in the region of high baryon densities. The Projectile Spectator Detector (PSD) is the forward hadron calorimeter that will be used in the CBM to measure the event centrality as well as the reaction plane orientation in heavy-ion collisions in the beam energy range of 2–11 〈em〉A〈/em〉GeV with beam interaction rates up to 10 MHz. The supermodule consisting of 9 modules has been assembled to explore the performance of the PSD. Its response has been studied with proton beams in the momentum range 2–10 GeV/c at the CERN Proton Synchrotron (PS) T9 and T10 beam lines. For the first time, the energy resolution and the linearity of the response have been measured at such low energies. The PSD operation under radiation conditions at the CBM, as well as the results of one PSD module measurements with irradiated photodetectors are discussed.〈/p〉〈/div〉

Description: 〈p〉Publication date: 11 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 911〈/p〉 〈p〉Author(s): Jan Grzegorz Hajnrych, Philippe Filliatre, Benoît Geslot〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A comparison between a few models of fission fragment penetration in several gases used in fission chambers is presented. To verify the energy loss of fission fragments, a comparison methodology was developed. It is based on comparative analysis of range experiments from third party publications with currently available models. We compared results from the SRIM code, the ICRU parametrization model implemented in Geant-4 and the LSS model. Albeit they are based on different hypotheses about the underlying physics that are not specific to fission fragments, those models reproduce fairly well the trend and order of magnitude of experimental data. Thanks to effective use of semi-empirical correlation fitted over large number of points, the SRIM code gives the closest results to experimental data: thus it is the model of choice for predicting and interpreting fission chambers’ signal.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 15 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): V. Cindro, S.H. Abidi, A.A. Affolder, M. Arratia, B. Ciungu, K. Dette, Z. Dolezal, C. Escobar, V. Fadeyev, C. García, I.M. Gregor, K. Hara, L.B.A. Hommels, Y. Ikegai, P. Kodys, G. Kramberger, J. Kroll, C. Lacasta, V. Latonova, D. Madaffari〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Miniature sensors with external dimensions of 10 mm x 10 mm were produced together with full-size sensors for the innermost ring (R0) of the end-cap part in the upgraded ATLAS inner tracker (ITk). AC- and DC-coupled n-type strips with three different pitches (wide, default and narrow) were processed on high-resistivity p-type FZ silicon substrates by Hamamatsu Photonics. The miniature sensors were irradiated with 70-MeV protons at CYRIC, Tohoku University (Japan) and reactor neutrons at the Jožef Stefan Institute (Slovenia) to three different 1-MeV neutron equivalent fluences: 0.5, 1 and 2 x 10〈sup〉15〈/sup〉〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈msub〉〈mrow〉〈mi〉n〈/mi〉〈/mrow〉〈mrow〉〈mi mathvariant="normal"〉eq〈/mi〉〈/mrow〉〈/msub〉〈/math〉cm〈sup〉−2〈/sup〉. The upper fluence range exceeds the highest anticipated in the innermost part of the ATLAS ITk-Strips over the HL-LHC lifetime (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si2.gif"〉〈mo〉∼〈/mo〉〈/math〉1.25 × 10〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si3.gif"〉〈msup〉〈mrow〉〈/mrow〉〈mrow〉〈mn〉15〈/mn〉〈/mrow〉〈/msup〉〈/math〉n〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si39.gif"〉〈msub〉〈mrow〉〈/mrow〉〈mrow〉〈mi mathvariant="normal"〉eq〈/mi〉〈/mrow〉〈/msub〉〈/math〉cm〈sup〉2〈/sup〉). The charge collection in the test sensors was evaluated systematically using a 〈sup〉90〈/sup〉Sr 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si5.gif"〉〈mi〉β〈/mi〉〈/math〉-source and an Alibava analogue readout system at reverse-bias voltages up to 1000 V.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 15 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): P. Cardarelli, G. Paternò, G. Di Domenico, E. Consoli, M. Marziani, M. Andreotti, F. Evangelisti, S. Squerzanti, M. Gambaccini, S. Albergo, G. Cappello, A. Tricomi, M. Veltri, O. Adriani, R. Borgheresi, G. Graziani, G. Passaleva, A. Serban, O. Starodubtsev, A. Variola〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉ELI-NP-GBS is a high-brilliance gamma source that will produce monochromatic beams in the energy range 0.2-19.5 MeV through inverse Compton scattering. In order to obtain a monochromatic beam a collimation of the emission is necessary. Depending on the energy, the angular aperture required to provide the design bandwidth 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mi〉Δ〈/mi〉〈/math〉E/E=0.5% is between 70 and 700 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si2.gif"〉〈mi〉μ〈/mi〉〈/math〉rad. This collimation is provided by a stack of 14 tungsten slits, arranged with a relative rotation around the beam axis, so that the overlap will be a continuously adjustable aperture. To monitor the operation and alignment of the collimation, a set of detectors will provide a complete characterization of the gamma beam, including the measurement of the transverse spatial distribution. For this task a gamma beam profile imager based on a thin scintillator screen and a high-resolution CCD-camera was developed. In this work we briefly present the status of the collimation system and beam profile imager, which were designed, assembled and are currently under test at INFN-Ferrara laboratories.〈/p〉〈/div〉

Description: 〈p〉Publication date: 11 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 911〈/p〉 〈p〉Author(s): N. Buzarbaruah, S.R. Mohanty, E. Hotta〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The adaption of new generation portable neutron sources has been increasingly marked in a wide range of research fields compared to the large-scale neutron generators. In this context, we have successfully demonstrated some essential parameters required for the emission of 2.45 MeV DD fusion neutrons from a steady state portable linear neutron source based on inertial electrostatic confinement scheme. The parameters that control the production of neutrons are the working pressure of the fuel gas, applied voltage, measured current and cathode geometries. The neutrons emitted from the source are confirmed using neutron monitor, bubble dosimeters, nuclear track detectors, and He-3 proportional counter. Presently, the device produces neutrons up to the order of 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mo〉∼〈/mo〉〈/math〉 10〈sup〉6〈/sup〉 n/sec at discharge voltage ranging from -60 kV to -80 kV, and discharge current of 20 mA to 30 mA.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 910〈/p〉 〈p〉Author(s): Yu.A. Chesnokov, V.A. Maisheev〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The problem of creation of high energy neutrino beams on the basis of modern and future circular proton accelerators with the help of traditional technology seems to be expensive and difficult. Because of this, we propose the solution of this problem based on the usage of focusing bent single crystals. In the paper we demonstrate the possibilities of acceptance and focusing of a pion beam with the help of a crystal optical lens system. As an illustration of these features the calculated neutrino fluxes for energy of circulating proton beam equal to 6.5 TeV are presented.〈/p〉〈/div〉

Description: 〈p〉Publication date: 11 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 911〈/p〉 〈p〉Author(s): L. Werner, M. Trunk, R. Gernhäuser, R. Gilles, B. Märkisch, Zs. Révay〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The cold neutron guide of the Prompt Gamma Activation Analysis (PGAA) instrument (Revay et al. 2015) at the Heinz Maier-Leibnitz Zentrum (MLZ) provides an excellent opportunity for neutron depth profiling (NDP) due to its high collimated neutron flux. We present the concept, layout and first measurements with the new N4DP facility set-up at this beamline. A special focus is put on background analysis and instrument characterization. We present measurements of a NIST reference sample and of boron-containing float glasses which are used for neutron optical waveguides. We give an outlook concerning the ongoing development of position-resolved NDP using silicon microstrip detectors.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 910〈/p〉 〈p〉Author(s): Z. Scholz, M. Millett, M. Schell〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Surrogate radiation sources are used to test detection equipment and train security personnel in the detection and interdiction of special nuclear material (SNM). Some current surrogate sources do not accurately match SNM energy spectra, including for HEU. In this research, we propose and investigate novel source configurations for higher fidelity surrogate SNM sources using thermal neutron capture reactions that result in prompt gammas. The objective is to create a surrogate source that has a more representative spectrum, low cost, and requires minimal security, special handling, and safety precautions.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 6 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): Ping Yang, Weiping Ren, Xiangming Sun, Guangming Huang, Le Xiao, Chaosong Gao, Xing Huang, Wei Zhou, Yashu Li, Jianchao Liu, Bihui You, Li Zhang, Jun Liu, Ying Zhang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Circular Electron Positron Collider (CEPC) is proposed as a Higgs factory for precision measurement of properties of the Higgs boson. The CEPC vertex detector requires low material budget, high spatial resolution, fast readout and low power consumption. Monolithic Active Pixel Sensor (MAPS), as one of the promising candidate technologies, has been studied within the R&D activities for the CEPC vertex detector. This proceeding introduces recent development of a MAPS prototype using the TowerJazz 180 nm CMOS Image Sensor process. Two different binary front-end circuits have been designed to explore an in-pixel front-end structure suitable for a compact pixel in combination with an in-matrix sparsified readout circuitry. To achieve high granularity together with fast readout speed, a new architecture of asynchronous data-driven matrix readout has been implemented. The prototype contains 128 rows and 64 columns featuring a small pixel pitch of 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mn〉25〈/mn〉〈mspace width="1em"〉〈/mspace〉〈mi mathvariant="normal"〉μ〈/mi〉〈mi mathvariant="normal"〉m〈/mi〉〈/math〉. The address of one hit pixel can be read out in 25 ns. This work presents the design of the prototype, which is currently under test.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 910〈/p〉 〈p〉Author(s): Seiichi Yamamoto, Hideo Nitta〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Gd〈sub〉3〈/sub〉(GaAl)〈sub〉5〈/sub〉O〈sub〉12〈/sub〉:Ce (GGAG) is a ceramic scintillator originally developed for X-ray CT, and it was also an excellent material for the development of an event-by-event-based radiation imaging detector when it was combined with a position sensitive photomultiplier (PSPMT). With the developed GGAG imaging detector, we found that the decay times for alpha particles and gamma photons were different. Also, we found that the decay times for alpha particles and beta particles were different. These characteristics are advantageous for developing an imaging detector for the simultaneous imaging of different types of radiation using pulse shape discrimination. Thus, we tested the separation of the images of the alpha particles and gamma photons using pulse shape discrimination. Also, we evaluated the separation of the alpha and beta particle images. In the pulse shape spectra, we could separate the peaks of Am-241 alpha particles and Cs-137 gamma photons with a peak-to-valley ratio (P/V) of 3.5. We obtained clearly separated images for Am-241 alpha particles and Cs-137 gamma photons using pulse shape discrimination. We could also separate the peaks of Am-241 alpha particles and Sr–Y-90 beta particles with a P/V of 1.5 in the pulse shape spectrum. We obtained separated images for Am-241 alpha particles and Sr–Y-90 beta particles using pulse shape discrimination. In addition, we could separate electrostatically collected natural alpha particles, Po-218 and Po-214, from the environmental beta particles and gamma photons using pulse shape discrimination. We conclude that the GGAG imaging detector is promising for simultaneous imaging and separating the images of different types of radiation using pulse shape discrimination.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 9 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): D. Bernard〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉No 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si64.gif"〉〈mi〉γ〈/mi〉〈/math〉-ray polarimeter sensitive above 1 MeV has ever flown space. 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si64.gif"〉〈mi〉γ〈/mi〉〈/math〉-ray polarimetry would be a new window on the radiative processes at work in cosmic sources, processes that produce linearly polarised emission, each of which with different polarisation fractions. The HARPO Collaboration has designed, built and characterised on beam a gas-TPC active target with which we have demonstrated for the first time the polarimetry of a linearly polarised MeV 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si64.gif"〉〈mi〉γ〈/mi〉〈/math〉-ray beam, from the analysis of the conversions to 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si65.gif"〉〈msup〉〈mrow〉〈mi〉e〈/mi〉〈/mrow〉〈mrow〉〈mo〉+〈/mo〉〈/mrow〉〈/msup〉〈msup〉〈mrow〉〈mi〉e〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈/mrow〉〈/msup〉〈/math〉 pairs.〈/p〉〈/div〉

Description: 〈p〉Publication date: 11 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 911〈/p〉 〈p〉Author(s): Songqing Tan, Rui Li, Chunlong Guo, Tao Shi, Yongqun Zhao, Xiaopeng Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper proposes a novel input power control strategy for high-power dynamic power supply for proton therapy. A buck chopper is staged in series between the input rectifier and the output chopper of the power supply to buffer the input power fluctuation, which can reduce the reactive power exchange between the power supply and power grid and reduce the power distribution requirements. The validity of this proposed control principle has been verified on a high-power dynamic dipole power supply for proton therapy.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 5 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): M. Mallamaci, B. Baibussinov, G. Busetto, D. Corti, A. De Angelis, F. Di Pierro, M. Doro, L. Lessio, M. Mariotti, R. Rando, E. Prandini, P. Vallania, C.F. Vigorito, for the CTA LST project〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A Silicon Photomultiplier (SiPM)-based photodetector is being built to demonstrate its feasibility for an alternative silicon-based camera design for the Large-Sized Telescope (LST) of the Cherenkov Telescope Array. It has been designed to match the size of the standard Photomultiplier Tube (PMT) cluster unit and to be compatible with mechanics, electronics and focal plane optics of the first LST camera. Here, we describe the overall SiPM cluster design along with the main differences with respect to the currently used PMT cluster unit. The fast electronics of the SiPM pixel and its layout are also presented. In order to derive the best working condition for the final unit, we measured the SiPM performances in terms of gain, photo-detection efficiency and cross-talk. One pixel, a unit of 14 SiPMs, has been built. We will discuss also some preliminary results regarding this device and we will highlight the future steps of this project.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 16 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): I. Mattei, G. Battistoni, M. De Simoni, Y. Dong, A. Embriaco, M. Fischetti, E. Gioscio, C. Mancini-Terracciano, M. Marafini, R. Mirabelli, S. Muraro, A. Sarti, A. Sciubba, E. Solfaroli Camillocci, G. Traini, S.M. Valle, V. Patera〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The use of C, He and O as beam particles in Particle Therapy (PT) treatments is getting more and more widespread as a consequence of the enhanced relative biological effectiveness and oxygen enhancement ratio of such projectiles with respect to protons. The advantages in the tumour control probability, related to the improved efficacy of ions, are calling for an online monitor of the dose release spatial distribution. Such technology is currently missing in PT treatments clinical routine. In this contribution the status of 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mi〉Z〈/mi〉〈mo〉〉〈/mo〉〈mn〉1〈/mn〉〈/math〉 ions PT treatments monitoring, exploiting the detection of either charged secondary particles or neutrons, is reviewed. While charged fragments can be used to provide an online feedback to the beam control system, by correlating their emission profile with the position of the Bragg peak, neutrons have to be monitored to improve the experimental description of the secondary radiation component that significantly contributes to an undesired and not negligible dose deposition far away from the tumor region, enhancing the risk of secondary malignancies development after the treatment. Two tracker detectors, employing scintillating fibers, are presented: the Dose Profiler designed for charged secondary fragments measurements and the MONDO tracker dedicated to the characterisation of the secondary fast and ultrafast neutron component, within the MONDO (MOnitor for Neutron Dose in hadrOntherapy) project.〈/p〉〈/div〉

Description: 〈p〉Publication date: 11 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 911〈/p〉 〈p〉Author(s): Huachang Liu, Jun Peng, Keyun Gong, Ahong Li, Bo Li, Qiang Chen, Xiaolei Wu, Mengxu Fan, Yun Wang, Peihua Qu, Shinian Fu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The China Spallation Neutron Source (CSNS) is an accelerator-based multidisciplinary user facility constructed in Dongguan, Guangdong, China. The injector of the CSNS accelerator consists of 4 conventional Alvarez DTL tanks, and it accelerates an H- beam from 3 MeV to 80 MeV. There is a series of accelerator physics and technology challenges in the DTL design and construction. The transverse focusing is arranged in a FFDD lattice utilizing a newly developed electromagnetic quadrupole magnets. The DTL cavity is copper-plated to enhance the electrical conductivity of the tank inner RF surface. There is not any space for steering magnet installing in the 36 m long DTL section, which leads to a rather high precision requirements for fabrication, installation and RF tuning. Benefited from the advanced fabrication technology and optimized tuning strategy, the CSNS DTL shows an excellent performance in the beam commissioning. The beam is successfully accelerated to 80 MeV with nearly 100% transmissions. The detailed physics and cavity design are described, construction and beam commissioning results are also shown.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 910〈/p〉 〈p〉Author(s): Y. Nagata, N. Kuroda, B. Kolbinger, M. Fleck, C. Malbrunot, V. Mäckel, C. Sauerzopf, M.C. Simon, M. Tajima, J. Zmeskal, H. Breuker, H. Higaki, Y. Kanai, Y. Matsuda, S. Ulmer, L. Venturelli, E. Widmann, Y. Yamazaki〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉An antihydrogen detector consisting of a thin BGO disk and a surrounding plastic scintillator hodoscope has been developed. We have characterized the two-dimensional positions sensitivity of the thin BGO disk and energy deposition into the BGO was calibrated using cosmic rays by comparing experimental data with Monte-Carlo simulations. The particle tracks were defined by connecting BGO hit positions and hits on the surrounding hodoscope scintillator bars. The event rate was investigated as a function of the angles between the tracks and the energy deposition in the BGO for simulated antiproton events, and for measured and simulated cosmic ray events. Identification of the antihydrogen Monte Carlo events was performed using the energy deposited in the BGO and the particle tracks. The cosmic ray background was limited to 12 mHz with a detection efficiency of 81%. The signal-to-noise ratio was improved from 0.22 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉s〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈mn〉1〈/mn〉〈mo〉∕〈/mo〉〈mn〉2〈/mn〉〈/mrow〉〈/msup〉〈/math〉 obtained with the detector in 2012 to 0.26 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉s〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈mn〉1〈/mn〉〈mo〉∕〈/mo〉〈mn〉2〈/mn〉〈/mrow〉〈/msup〉〈/math〉 in this work.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 9 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): J. Zorn, for the CTA GCT project〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Compact High-Energy Camera (CHEC) is a design option proposed for the small-sized telescopes (SSTs) of the Cherenkov Telescope Array (CTA), focusing on the gamma-ray detection at the upper end of the gamma-ray spectrum (from 1 TeV up to around 300 TeV). Thanks to the use of dual-mirror, Schwarzschild-Couder (SC) optics, CHEC can be – by design – very compact (0.5 m 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mo〉×〈/mo〉〈/math〉 0.5 m), light (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si15.gif"〉〈mo〉∼〈/mo〉〈/math〉50 kg), and low-cost (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si15.gif"〉〈mo〉∼〈/mo〉〈/math〉150€). Using electronics based on TARGET (TeV Array Read-out with GSa/s sampling and Event Trigger) application-specific integrated circuits (ASICs) and field programmable gate arrays (FPGAs) allows a flexible trigger scheme and continuous sampling at 1 GSa/s. Full waveforms for all 2048 pixels are read out without loss at over 600 Hz. Two full prototype cameras have been developed. The first, based on multi-anode photomultipliers (MAPMs) as photosensors, was successfully characterised in the laboratory and during on-telescope campaigns where it saw Cherenkov light from air showers, as the first CTA camera prototype and the first camera ever using SC optics. The second, featuring upgraded ASICs and Silicon photomultipliers (SiPMs), is under commissioning at the Max-Planck-Institut für Kernphysik in Heidelberg.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 5 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): S. Abovyan, V. Danielyan, M. Fras, O. Kortner, H. Kroha, R. Richter, Y. Zhao, A. Baschirotto, M. De Matteis, F. Resta〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In order to fully exploit the physics potential of the ATLAS experiment at the HL-LHC, the trigger rate of and maximum latency of the first-level trigger system will be increased to 1 MHz and 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mn〉10〈/mn〉〈mspace width="1em"〉〈/mspace〉〈mi mathvariant="normal"〉μ〈/mi〉〈mi mathvariant="normal"〉s〈/mi〉〈/math〉, respectively. In addition, a new first-level muon track trigger with high momentum resolution based on the ATLAS precision Muon Drift-Tube (MDT) chambers will be employed which requires triggerless readout. The TDC ASICs of the current front-end electronics of the MDT chambers are incompatible with these requirements. The front-end boards, each with a TDC chip and three 8-channel amplifier–shaper–discriminator (ASD) chips have to be replaced. Therefore, a new octal ASD2 ASIC has been developed in modern 130 nm IBM/Global Foundries CMOS technology. The chip also contains a Wilkinson ADC to perform both time-over-threshold and signal charge measurement. The ASD design has been fully qualified for the serial production of 80000 chips for ATLAS. The performance in terms of signal rise time and channel uniformity significantly surpasses the one of the previous chip while keeping the power consumption constant. In addition to the characterization with test pulses, several chips have been mounted on the front-end boards and tested in a muon beam at the Gamma Irradiation Facility GIF++ at CERN up to high counting rates where the superior drift time and spatial resolution becomes evident.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 913〈/p〉 〈p〉Author(s): J.P. Holzbauer, C. Contreras, Y. Pischalnikov, D. Sergatskov, W. Schappert〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉SRF cavity quality factors can be accurately measured using RF-power based techniques only when the cavity is very close to critically coupled. This limitation is from systematic errors driven by non-ideal RF components. When the cavity is not close to critically coupled, these systematic effects limit the accuracy of the measurements. The combination of the complex base-band envelopes of the cavity RF signals in combination with a trombone in the circuit allow the relative calibration of the RF signals to be extracted from the data and systematic effects to be characterized and suppressed. The improved calibration allows accurate measurements to be made over a much wider range of couplings. Demonstration of these techniques during testing of a single-spoke resonator with a coupling factor of near 7 will be presented, along with recommendations for application of these techniques.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 910〈/p〉 〈p〉Author(s): Mukhtar Ahmed Rana〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The influence of preservation period of CR-39 detectors, in refrigerator and in the laboratory atmosphere, on bulk etch rate is studied. The effect of etching solution usage time on the bulk etch rate is also investigated. Analyses and quantitative results in the said cases are presented. Finally, precision results on the use of CR-39 as a charged particle detector are presented in a systematic manner. These results are selected from our radiation detection and measurement experiments, ranged over last two decades. Selected results (unpublished and published) include CR-39 measurements of 5.9 MeV antiprotons, 6.12 MeV alpha particles and spontaneous fission fragments of 〈sup〉252〈/sup〉Cf. Our published results, presented here, are further analyzed and presented in comparison with new results and discussion. Experimental procedures of exposures, chemical etching, track measurements using the optical microscopy are described, keeping in view the new users and research students. Computer codes TRACK_Vision and SRIM were employed to provide a comparison with measurements of track parameters, where possible.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 8 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): H. Gómez〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Muon tomography, or muography, stands out as a non-invasive technique for the scanning of big objects internal structure. It relies on the measurement of the direction changes or absorption of atmospheric muons when crossing the studied object. For the first case, the trajectory reconstruction of muons upstream and downstream the object, provides information to generate its 3D density map. For bigger objects, a 2D map can be obtained by measuring the absorption for different incident directions. Proposed several decades ago, the performance achieved in particle detectors in the last years, specially in terms of stability, robustness and precision, has enlarged the possible applications of this technique.〈/p〉 〈p〉Bulk Micromegas represent a well-known technology suitable for the construction of muon telescopes based on these detectors. Thus autonomous and portable instruments have been conceived and constructed at 〈em〉Commissariat à l’Énergie Atomique et aux Énergies Alternatives〈/em〉 (CEA), being able to perform measurements 〈em〉in-situ〈/em〉, next to the studied objects. Furthermore, a Geant4-based simulation framework, capable to handle 3D models of the studied objects, is also being implemented to be used as support tool during the feasibility studies and for data analysis and results interpretation.〈/p〉 〈/div〉

Description: 〈p〉Publication date: Available online 12 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): B. Canion, J. Dreyer, O. Drury, D. Trombino, K. Nelson, B. Seilhan, S. Labov, K. Jarman, B. McDonald, M. Zalavadia, M. Myjak, D. Pfund, J. Forrester, G. Lawson〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉We investigate a new safeguards approach for verification of uranium processing operations via standoff measurement of UF〈sub〉6〈/sub〉 cylinder transports entering and leaving a facility. Current safeguards verification at facilities with UF〈sub〉6〈/sub〉 cylinders includes attended enrichment measurements of several randomly-selected cylinders using handheld instruments with inspection of all the cylinders typically only once a year. This approach requires significant inspector effort and can only be performed intermittently. Here we explore an unattended, multi-sensor enrichment measurement system that can operate continuously on cylinders in motion. Such an approach could be used to enhance continuity of knowledge by verifying that all shipments entering and leaving a facility are consistent with declared operations.〈/p〉 〈p〉The challenges in developing a standoff enrichment technique include limited statistical significance of the collected data, and interpreting the complex signatures from a shipment of UF〈sub〉6〈/sub〉 cylinders. These signatures vary with cylinder properties (e.g. the fuel cycle history, cylinder history, material distribution, material age, etc.) and measurement conditions (e.g. speed and distance of vehicle, detector response, cylinder orientation, attenuation from overpack and vehicle, etc.).〈/p〉 〈p〉In this paper, we demonstrate that we can extract useful enrichment signatures from standoff measurements of UF〈sub〉6〈/sub〉 cylinders entering and leaving a facility. Our initial analysis demonstrates a measurable difference in enrichment-related signatures from a cylinder in motion, measured with modest detection efficiency from several meters away. We also demonstrate that the inclusion of vehicle tracking increases the signal-to-noise ratio (SNR) of our radiation signatures, and decreases uncertainty of parameters needed for enrichment analysis, e.g. distance and velocity.〈/p〉 〈/div〉

Description: 〈p〉Publication date: Available online 6 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): G. Matarrese, P.A.P. Calò, F. Corsi, C. Marzocca, S. Petrignani〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉High-gain photomultiplier detectors are employed in an increasing number of applications in different fields to evaluate with great accuracy the occurrence time of light flashes composed by few or even single photons. Examples of these application fields are medical imaging, astroparticle and high energy physics, laser spectroscopy and LIDAR. To fulfill a good single photon timing accuracy, in the range of few hundreds of picoseconds, not only detectors with intrinsic excellent timing resolution (photomultiplier tubes, microchannel plated detectors, silicon photo multipliers, etc.) must be used, but the very first front-end amplifier (FEA) stage, used to read-out the detector, must also be carefully chosen and designed.〈/p〉 〈p〉We compare here three commonly used solutions for the FEA, from the point of view of the best achievable timing resolution: the charge sensitive amplifier (CSA), the voltage amplifier (VA) and the current buffer (CB). The results show that the CSA solution is limited in terms of frequency response by the usually large equivalent capacitance of the detector and that, surprisingly, the presence of the parasitic inductance 〈em〉L〈/em〉, due to interconnection detector-FEA, has a noise shaping effect which favourably affects the timing accuracy of the CB over the VA configuration. To support this study, simulations of simple implementations of the compared FEA solutions have been performed, under the same conditions.〈/p〉 〈p〉Moreover, with reference to a given detector and to a particular value of 〈em〉L〈/em〉, we show how the best timing accuracy of the CB is obtained by selecting an appropriate combination of input resistance and bandwidth of the FEA.〈/p〉 〈/div〉

Description: 〈p〉Publication date: Available online 5 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): I. Semeniouk, D. Bernard〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We present the C++ implementation of an event generator for linearly-polarized gamma-ray conversions to 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si3.gif"〉〈mi〉γ〈/mi〉〈mo〉→〈/mo〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉e〈/mi〉〈/mrow〉〈mrow〉〈mo〉+〈/mo〉〈/mrow〉〈/msup〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉e〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈/mrow〉〈/msup〉〈/math〉 pairs. The generator uses the full 5D Bethe–Heitler probability density function for the generation of the 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si3.gif"〉〈mi〉γ〈/mi〉〈mo〉→〈/mo〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉e〈/mi〉〈/mrow〉〈mrow〉〈mo〉+〈/mo〉〈/mrow〉〈/msup〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉e〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈/mrow〉〈/msup〉〈/math〉 pair and for the recoil of the target nucleus. The same code is used for triplet generation. We present a verification of the model by comparing sample distributions with theoretical predictions.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 5 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): B. Juste, S. Morató, C. García, R. Miró, G. Verdú〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Different methods exist to verify bunkers design for radiation therapy medical facilities; analytical methods based on simplified equations and Monte Carlo methods. One of the main purposes of this work is to present the advantages of using Monte Carlo simulation to verify radiotherapy bunker shielding design. This methodology is more accurate and characterizes not only the fluence and dose three-dimensionally, but also the energy spectrum of particles generated by the LinAc. The other main purpose of the work is to analyze the importance of the generated photoneutrons when the LinAc emits high-energy photon beams (above 8 MeV), since numerous studies have found that these neutrons can expose the patient and clinical staff to non-negligible dose. The main novelty introduced by this work, is the creation of more realistic geometry simulation models to represent the radiotherapy facility by using CAD and meshes technologies which can be imported to MCNP6 Monte Carlo code. Results obtained using these bunker simulation models have been validated experimentally at the Hospital Universitari i Politècnic La Fe de Valencia facilities using two different neutron detectors; the neutron meter LB 6411 (designed between Berthold and Karlsruhe Research Center) and neutron detector model 42 - 41L (Ludlum, Prescila). Neutron dose results obtained with Monte Carlo and those measured experimentally fit correctly, validating this analysis methodology.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 9 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): L. Wiik-Fuchs, L. Diehl, R. Mori, M. Hauser, K. Jakobs, S. Kühn, U. Parzefall, A.A. Affolder, V. Fadeyev, C. García, C. Lacasta, D. Madaffari, U. Soldevila, Y. Unno〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The upgrade of the LHC to the High Luminosity LHC will challenge the silicon strip detector performance with high fluence and long operation time. Sensors have been designed and tests on charge collection and electrical performance have been carried out in order to evaluate their behaviour. Besides that, it is important to understand and predict the long-term evolution of the sensor properties. In this work, detailed studies on the annealing behaviour of ATLAS12 strip sensors designed by the ITK Strip Sensor Working Group and irradiated from 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si3.gif"〉〈mn〉5〈/mn〉〈mo〉×〈/mo〉〈mn〉1〈/mn〉〈msup〉〈mrow〉〈mn〉0〈/mn〉〈/mrow〉〈mrow〉〈mn〉13〈/mn〉〈/mrow〉〈/msup〉〈msub〉〈mrow〉〈mi mathvariant="normal"〉n〈/mi〉〈/mrow〉〈mrow〉〈mi mathvariant="normal"〉eq〈/mi〉〈/mrow〉〈/msub〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉cm〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈mn〉2〈/mn〉〈/mrow〉〈/msup〉〈/math〉 to 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si4.gif"〉〈mn〉2〈/mn〉〈mo〉×〈/mo〉〈mn〉1〈/mn〉〈msup〉〈mrow〉〈mn〉0〈/mn〉〈/mrow〉〈mrow〉〈mn〉15〈/mn〉〈/mrow〉〈/msup〉〈msub〉〈mrow〉〈mi mathvariant="normal"〉n〈/mi〉〈/mrow〉〈mrow〉〈mi mathvariant="normal"〉eq〈/mi〉〈/mrow〉〈/msub〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉cm〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈mn〉2〈/mn〉〈/mrow〉〈/msup〉〈/math〉 are presented. Systematic charge collection and leakage current measurements have been carried out during the annealing process until break-down or the appearance of charge multiplication. The annealing was carried out, separating the sensors into two groups being either annealed at 23 °C or 60 °C. Sensors showing charge multiplication have been then kept at high voltage for a long time in order to monitor their stability. The difference in the annealing behaviour between the two temperatures has been analysed and compared to similar measurements on n-type sensors and with a theoretical model. From the impedance measurements for the samples irradiated to low fluences it was possible to extract the effective doping concentration. This was compared to similar measurements on n-type sensors and with a theoretical model.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 9 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): Carlos Granja, Karel Kudela, Jan Jakubek, Pavel Krist, David Chvatil, Jan Stursa〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We evaluate and characterize the directional response of the semiconductor pixel detector Timepix to charged particles and secondary cosmic rays. The detector granularity and per-pixel spectrometric response enable to perform directional sensitive tracking of energetic charged particles in wide field-of-view. In the highly integrated MiniPIX readout the detector serves as a miniaturized, low-power and easily deployable particle micro-tracker. Angular measurements require normalization for the acceptance angle and geometric factor which are described and taken into account. The methodology and evaluation of directional response are developed for light charged particles and atmospheric secondary cosmic rays. Tests and calibration of angular resolution were performed with electron and proton beams. Resulting angular distributions are expressed in terms of elevation and azimuth angles in 14 bins and 36 bins, respectively, over the full 2〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mi〉π〈/mi〉〈/math〉 acceptance range. For zenith angle 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si17.gif"〉〈mi〉β〈/mi〉〈/math〉 〉 28° the angular distribution is fitted by 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si3.gif"〉〈mo〉∼〈/mo〉〈/math〉 cos 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si4.gif"〉〈msup〉〈mrow〉〈/mrow〉〈mrow〉〈mi mathvariant="normal"〉n〈/mi〉〈/mrow〉〈/msup〉〈/math〉 (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si17.gif"〉〈mi〉β〈/mi〉〈/math〉) with n = 2.0 ± 0.2 expected from secondary cosmic ray muon distribution.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 910〈/p〉 〈p〉Author(s): G. Mauri, M. Mariotti, F. Casinini, F. Sacchetti, C. Petrillo〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The application of Si sensors coupled to Gd converters as thermal neutron counters is assessed in a series of test experiments on the neutron beam, among which scattering from standard samples. The prototype 1d detector is a Si microstrip sensor directly coupled to natural Gd converter and equipped with standard front-end electronics. The raw scattering data, collected by interfacing the detector with the data acquisition system available at the neutron source, show advantages and limits of this technology when applied to neutron detection. To improve the performances of the Si-based detector by means of an optimized discrimination of the neutron signals from noise and background radiation, a pulse shape analysis method is proposed. The effectiveness of this method is then explored by experimental tests on the neutron beam of two more prototype detectors, namely a PIN diode coupled to   〈sup〉157〈/sup〉Gd〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si138.gif"〉〈msub〉〈mrow〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msub〉〈/math〉O〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si139.gif"〉〈msub〉〈mrow〉〈/mrow〉〈mrow〉〈mn〉3〈/mn〉〈/mrow〉〈/msub〉〈/math〉 converters, and a Silicon photo-multiplier (SiPM) coupled to neutron scintillators. This study is aimed to real time applications and single event storage of the neutron information in time of flight instrumentation.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 31 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): D.M. Kasparek, B.S. McDonald, A.J. Gilbert, R.S. Wittman〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The International Atomic Energy Agency (IAEA) is responsible for verifying the mass of elemental uranium in various forms (powders, pellets, scrap) as part of inspections at nuclear fuel fabrication facilities. Current methods require in-field dissolution chemistry, which is time consuming and imposes operational challenges. Pacific Northwest National Laboratory (PNNL) is developing a prototype spectral x-ray radiography (SpecX) nondestructive assay system for noninvasive material mass quantification of uranium-bearing powders. The SpecX system uses a custom material estimation algorithm, which requires a high-fidelity pixel-by-pixel detector response model for accurate quantification. We performed a detailed characterization and built a model of a High-Energy X-ray Imaging Technology (HEXITEC) CdTe pixelated spectral detector. Here we present the detector characterization which led to that model, including a determination of the pixel-wise energy calibration, the detection efficiency, the detector uniformity, the detector stability, and a comparison of methods to remove charge-shared events.〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Chuanjun Li, Rui Guo, Shengya He, Weidong Xuan, Xi Li, Yunbo Zhong, Zhongming Ren〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The formation of the microstructures in the hypo- and hypereutectic Al〈img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉Cu alloys in the steady magnetic field (SMF) was investigated using the conventional quenching technique. In comparison with quenched structures without the SMF, the additional bulky phases, i.e. θ-Al〈sub〉2〈/sub〉Cu phase and the supersaturated α solid solution, were found to form in the Al-26 wt%Cu and Al-45 wt%Cu alloys quenched in the SMF, respectively. The temperature measurements showed that the maximum cooling rate of the quenched sample in the SMF was markedly higher than that without the SMF and thus a larger undercooling was obtained in the SMF. The microstructure formation in the SMF can be rationalized using the Al〈img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉Al〈sub〉2〈/sub〉Cu phase diagram with metastable extensions and the coupled growth zone.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Wenmin Guo, Bin Liu, Yong Liu, Tianchen Li, Ao Fu, Qihong Fang, Yan Nie〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Refractory high-entropy alloys (RHEAs) are promising high-temperature structural materials due to their high melting point and extraordinarily high yield strength. However, their industrial application is greatly restricted due to their limited room-temperature ductility. In the present investigation, a ductile and strong single-phase NbTaTiV RHEA was synthesized by powder metallurgy method. Effects of the sintering temperature on the phase formation, microstructural evolution and the mechanical properties of the NbTaTiV RHEA were characterized. The results show that the NbTaTiV RHEA sintered at 1700 °C has an equiaxed single bcc phase microstructure, no obvious porosity and compositional segregation can be observed. The alloy exhibits a relatively high hardness of 510 HV, yield strength of 1.37 GPa, and compressive fracture strength of 2.19 GPa with a high fracture strain of 23% at room temperature. Typical strain softening and steady state flow occur during compressive deformation at high temperatures. During deformation at 1000 °C, the alloy still exhibits high yield strength of 437 MPa with a compression strain over than 40%. The outstanding mechanical properties is mainly attributed to the homogeneous and fine microstructures, and solid solution strengthening effect. It can be concluded that the powder metallurgy is a promising way for preparing ductile RHEAs with outstanding comprehensive mechanical properties.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Thiquynhxuan Le, Qi Wang, A.V. Ravindra, Xiteng Li, Shaohua Ju〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel microwave heating process for the synthesis of zeolite-Y from spent fluid catalytic cracking (SFCC) catalyst has been proposed in this work. The SFCC catalyst is firstly activated in microwave field by acid solution and then used as an aluminum source for the synthesis of zeolite-Y. The activation effect of hydrochloric acid and oxalic acid on the SFCC catalyst, and the synthesis effects of zeolite-Y production from the activated SFCC catalyst under microwave are studied by ICP, XRD, SEM, and N〈sub〉2〈/sub〉 sorption studies. The results show that microwave-assisted acid activation process can facilitate the formation of the active γ-Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 and as well enhance the crystallinity of zeolite-Y in the SFCC catalyst, which is beneficial for the synthesis of zeolite-Y. Compared with the inactivated SFCC catalyst, the activated SFCC catalyst has a larger specific surface area and a lower contaminated metal content. The specific surface areas of SFCC catalyst after activation by hydrochloric acid and oxalic acid are 197.1 and 113.6 m〈sup〉2〈/sup〉/g, respectively, indicating better activation by hydrochloric acid compared to oxalic acid in the microwave field. The results demonstrate that increasing the synthesis temperature and prolonging the crystallization time favor the growth of zeolite-Y crystal particles, however, zeolite-Y partially transforms into zeolite-P. The priority of different aluminum sources in zeolite-Y synthesis is: hydrochloric acid activated SFCC catalyst 〉 oxalic acid activated SFCC catalyst 〉 inactivated SFCC catalyst. The zeolite-Y having a particle size range of 0.3–1 μm is successfully synthesized from the activated SFCC catalyst at 100 °C for 2 h under microwave at 2 kg/cm〈sup〉2〈/sup〉 pressure and 1000 W power.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Qing Zhou, Yin Du, Yue Ren, Wangwang Kuang, Weichao Han, Haifeng Wang, Ping Huang, Fei Wang, Jian Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Friction and wear are the two most important properties that determine the long-term performances of metallic glasses as much as strength and ductility. With this in mind, a multilayered strategy was proposed to improve the nano-scratching properties of metallic glass thin films and the well-characterized Zr-based metallic glasses were chosen to be the representative model materials in current work. It was found that the metallic glass could exhibit improved wear resistance and reduced friction coefficient if it is made in the form of multilayers. The complexity in the temporal scale of the lateral force signal is investigated, elucidating the inhomogeneous (and homogeneous) shear-banding processes during the nanoscratching process. The statistical and dynamic analyses of the stick-slip behaviors showed a transition from a chaotic to a self-organized critical state in the multilayers, indicating that the hetero-interfaces promote extensive shear band-interface interactions and induce the scratch hardening effect, both of which are responsible to the excellent tribological properties. The current work not only highlights the significant roles of hetero-interfaces in improving the nano-tribological properties but also make the multilayered metallic glass thin films a promising candidate towards structural and functional applications for metallic glasses.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838818339446-fx1.jpg" width="280" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): P. Sochacka, A. Miklaszewski, M. Jurczyk〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Titanium-based alloys with fine grain structure represent a class of engineering materials that can exhibit a unique combination of properties. This paper presents the structural evolution of the β phase in Ti-x at. % Mo (x = 10, 23, 27, 31 and 35) alloys synthesized by mechanical alloying with different milling times between 15 min and 48 h and powder metallurgical process with cold powder compaction and sintering or interchangeably hot pressing. The binary alloys were characterized by X-ray diffraction, scanning electron microscopy, chemical composition determination as well as density and porosity measurements. The influence of the chemical composition and method of processing on the final microstructure, and mechanical properties of bulk alloys were studied. The mechanically alloyed Ti23Mo, Ti27Mo and Ti31Mo materials upon sintering at 800 °C for 5 min led to the formation of single β type phase alloys. All these β-type alloys have elastic modulus lower than CP microcrystalline α-Ti, but their hardness is nearly 3 times higher (approx: 460 HV〈sub〉0.3〈/sub〉). The present study has demonstrated that these single phase β-type alloys with fine grain microstructure can be fabricated by the application of hot pressing of mechanically alloyed powders at the temperature below α→β transus (800 °C).〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092583881833891X-fx1.jpg" width="145" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Li Wan, Yun-Lai Deng, Ling-Ying Ye, Yong Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The natural ageing effect on artificial ageing kinetics of Al-Zn-Mg alloy has been studied using small angle X-ray scattering, transmission electron microscopy and mechanical testing methods. The results have demonstrated that with 72 hours natural ageing treatment prior to pre-ageing process can inhibit following natural ageing effect. Samples with direct pre-ageing treatment after quenching from solution temperature exhibit significant natural ageing effect subsequently. The strengthening effect is mainly attributed to the formation of fine GP-zones with particle sizes of less than 1 nm. The microstructures characterization has shown that these GP-zones may transform to precursor of η′ precipitate during pre-ageing process if their size reached a critical size. These precursor of η′ precipitate with the size of ∼1 nm–∼1.2 nm are stable at room temperature.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): A. Brzoza, M. Kowalczyk, A. Wierzbicka-Miernik, P. Czaja, W. Maziarz, A. Wójcik, J. Wojewoda-Budka, M. Sikora, J. Dutkiewicz, M.J. Szczerba〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Ni-Mn-Ga-Co-Cu melt spun ribbons were investigated in the as-cast and annealed states. The initial microstructure of the ribbons was highly anisotropic along the growing direction and was characterized by three different regions of equiaxed, columnar and dendritic grains. At ambient temperature, the microstructure was composed of two martensitic phases, i.e. non-modulated and seven-layer modulated, and the high temperature L2〈sub〉1〈/sub〉 austenite phase. The stabilization of the austenite phase was a consequence of a strong grain size reduction, especially close to the “contact” side of the ribbons. Subsequent annealing at 823 K triggered atomic ordering, which promoted an improvement in the magnetization. Additional annealing at 1173 K brought about a substantial refinement of the microstructure. The ribbon structure changed to a single non-modulated martensite phase, whereas on a microstructural level, the grains and martensitic plates coarsened considerably. The annealed ribbons resembled oligo-crystalline materials and may cause interest for magnetic field-induced strain applications.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838818339057-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Priyanka Nehla, Clemens Ulrich, Rajendra S. Dhaka〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report the structural, transport, electronic, and magnetic properties of Co〈sub〉2〈/sub〉FeGa Heusler alloy nanoparticles. The Rietveld refinements of x-ray diffraction (XRD) data with the space group Fm〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mrow〉〈mover accent="true"〉〈mn〉3〈/mn〉〈mo〉¯〈/mo〉〈/mover〉〈/mrow〉〈/math〉m clearly demonstrates that the nanoparticles are of single phase. The particle size (D) decreases with increasing the SiO〈sub〉2〈/sub〉 concentration. The Bragg peak positions and the inter-planer spacing extracted from high-resolution transmission electron microscopy image and selected area electron diffraction are in well agreement with data obtained from XRD. The coercivity initially increases from 127 Oe to 208 Oe between D = 8.5 nm and 12.5 nm, following the D〈sup〉−3/2〈/sup〉 dependence and then decreases with further increasing D up to 21.5 nm with a D〈sup〉−1〈/sup〉 dependence, indicating the transition from single domain to multidomain regime. The effective magnetic anisotropic constant behaves similarly as coercivity, which confirms this transition. A complex scattering mechanisms have been fitted to explain the electronic transport properties of these nanoparticles. In addition we have studied core-level and valence band spectra using photoemission spectroscopy, which confirm the hybridization between 〈em〉d〈/em〉 states of Co/Fe. Further nanoparticle samples synthesized by co-precipitation method show higher saturation magnetization. The presence of Raman active modes can be associated with the high chemical ordering, which motivates for detailed temperature dependent structural investigation using synchrotron radiation and neutron sources.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Xin Zhang, Ming Zhang, Tianyu Cui, Jinman Li, Qingsuo Liu, Haibo Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The microstructure and the shape memory effect of Cu-13.0Al-4.0Ni high temperature shape memory alloys doped with different contents of boron (0.25 wt%, 0.5 wt%, 1.0 wt%, and 2.0 wt%) were studied in this paper. According to the obtained results, it was observed that the microstructure and the shape memory effect were sensitive to the addition of boron, and the addition of boron not only enhanced the mechanical properties of the Cu-13.0Al-4.0Ni alloy, but also greatly improved the shape memory effect of the alloy. The fracture of martensite changed from intergranular fracture to transgranular cleavage fracture. In addition, it was found that the highest shape memory effect was achieved by the addition of 0.25 wt% boron.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Sen Gao, Xian Zhang, Qingfeng Zeng, Shiyu Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Crystalline 〈em〉α〈/em〉-TeO〈sub〉2〈/sub〉 was investigated at ambient pressure using 〈em〉ab initio〈/em〉 calculations. The effect of pressure on 〈em〉α〈/em〉-TeO〈sub〉2〈/sub〉 was studied from 0 to 10 GPa. The lattice parameters and elastic constants calculated by LDA and GGA method at 0 GPa both agree with the available theoretical and experiment results. The elastic constants 〈em〉C〈/em〉〈sub〉〈em〉ij〈/em〉〈/sub〉, the bulk modulus 〈em〉B〈/em〉, the shear modulus 〈em〉G〈/em〉, Young's modulus 〈em〉E〈/em〉, and the ductile and brittle character (〈em〉B〈/em〉/〈em〉G〈/em〉) were calculated and examined in detail. It was found that the calculated universal anisotropy index indicated that 〈em〉α〈/em〉-TeO〈sub〉2〈/sub〉 has anisotropy under 0 GPa, and with the pressure increases, its elastic anisotropy increases. Furthermore, from the mechanical stability criteria, it is show that the structure of tetragonal 〈em〉α〈/em〉-TeO〈sub〉2〈/sub〉 is not stable above 5.1 GPa. Finally, the electronic and optical properties were also investigated, and the results show that, on increasing the external pressure, the energy bandgap increases, with the optical spectrum exhibiting anisotropy in the 〈em〉x〈/em〉 and 〈em〉z〈/em〉 directions and a small blue shift under pressure.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Jens Reiser, Andreas Hoffmann, Johannes Hain, Ute Jäntsch, Michael Klimenkov, Jörg Hohe, Tobias Mrotzek〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉This paper describes a systematic analysis of liquid-phase infiltrated molybdenum (Mo) copper (Cu) composites, deformed by various levels, and elucidates the impact of (i) the copper content, and (ii) the rolling reduction on the evolution of the material properties. The rolling-induced change of the thermo-physical properties can be traced back to (ii-a) the evolution of the geometry (viz. the flattening of the molybdenum and the copper phase during rolling) and (ii-b) the evolution of the crystallographic texture.〈/p〉 〈p〉Four infiltrated ingots with a copper content of 23, 39, 48 and 54 vol % were produced. Each ingot was gradually rolled down to a final degree of deformation of 0.5, 1, 1.5, 2 and 2.38, which corresponds to a rolling reduction of 39%, 63%, 78%, 86% and 90%. In summary, four material compositions (23, 39, 48 and 54 vol % Cu) in six conditions (as-infiltrated and five as-rolled conditions) were examined.〈/p〉 〈p〉The evolution of the microstructure is correlated with the evolution of the mechanical and thermo-physical properties such as hardness (HV2), Young's modulus, 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mrow〉〈mi〉E〈/mi〉〈/mrow〉〈/math〉, electrical conductivity, 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈mrow〉〈mi〉σ〈/mi〉〈/mrow〉〈/math〉, thermal conductivity, 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si3.gif" overflow="scroll"〉〈mrow〉〈mi〉k〈/mi〉〈/mrow〉〈/math〉, and the coefficient of thermal expansion, 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si4.gif" overflow="scroll"〉〈mrow〉〈mi〉α〈/mi〉〈/mrow〉〈/math〉 (CTE, in the range of 350 °C (623 K) – 750 °C (1023 K)).〈/p〉 〈p〉It was found, that the same thermal conductivity can be gained by using either a low copper-content composite that features a low degree of deformation or by using a high copper-content composite that was rolled down to a high degree of deformation.〈/p〉 〈p〉Furthermore, we were able to demonstrate that peculiarities in the CTE-over-T curves can be traced back to the plastic deformation of the copper phase, which is affected by rolling-induced residual stresses and recrystallisation processes during the CTE measurement.〈/p〉 〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838818339094-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 775〈/p〉 〈p〉Author(s): Feng Hong, Haiming Cheng, Yan Song, Dan Li, Guixia Liu, Wensheng Yu, Jinxian Wang, Xiangting Dong〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Non-rare-earth red phosphors as alternative to commercial (oxy) nitride phosphors have attracted considerable attention for energy-efficient warm white light-emitting diodes (WLEDs). An excellent narrow-band red emission K〈sub〉2〈/sub〉GeF〈sub〉6〈/sub〉:Mn〈sup〉4+〈/sup〉 product was successfully obtained through co-precipitation method. The crystal structure, morphology, composition and optical properties of K〈sub〉2〈/sub〉GeF〈sub〉6〈/sub〉:Mn〈sup〉4+〈/sup〉 samples were investigated in details 〈em〉via〈/em〉 X-ray powder diffraction (XRD), field emission scanning electron microscope (FESEM), energy dispersive spectrometry (EDS) and photoluminescence spectra, respectively. Mn〈sup〉4+〈/sup〉 activated K〈sub〉2〈/sub〉GeF〈sub〉6〈/sub〉 red phosphor possesses two strong and wide absorption bands in the region of 300–500 nm, which can be applied to UV and blue LED chips and bright intense red light (635 nm) with high color purity. Simultaneously, mechanisms of concentration and temperature quenching were systematically elucidated. After a systematic investigation, the luminescence properties of K〈sub〉2〈/sub〉GeF〈sub〉6〈/sub〉:Mn〈sup〉4+〈/sup〉 have been optimized by changing synthetic conditions, such as the doping concentration, the concentration of HF, the potassium source, the amount of KF and the addition of surfactant. The red phosphor K〈sub〉2〈/sub〉GeF〈sub〉6〈/sub〉:Mn〈sup〉4+〈/sup〉 was packaged 〈em〉via〈/em〉 mixing commercial YAG:Ce yellow phosphor, an outstanding warm WLED with low CCT (3882 K), high CRI (Ra = 90.4) and high luminous efficacy (LE) of 125.84 lm/W has been obtained, implying that K〈sub〉2〈/sub〉GeF〈sub〉6〈/sub〉:Mn〈sup〉4+〈/sup〉 is the potential red phosphor for warm WLEDs.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838818331839-fx1.jpg" width="329" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Guozhong Huang, Peipei Zhang, Zhiming Bai〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel ZnO nanowire arrays (NAs)/graphene(G)/CdS/electrolyte heterojunction was successfully prepared via a simple three-step synthesis method when applied for photoelectrochemical type self-powered UV–visible photodetectors. Under zero bias, the responsivities of the self-powered UV–visible photodetectors on the basis of ZnO NAs/G/CdS/electrolyte heterojunctions are 27.3 mA/W and 4.3 mA/W for the UV and visible light, respectively, with fast rise and decay times (5 ms). Graphene improves the response of ZnO NAs to UV and visible light to a certain extent owing to its excellent charge-collecting ability and the acceleration of carrier separation and transference. After covering photosensitive CdS nanoparticles, the response to visible light is greatly increased because of the type II energy band structure of ZnO/CdS. It could be inferred from the evidence that the ZnO NAs/G/CdS/electrolyte heterojunction performs effectively in the aspect of self-powered UV–visible detection.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): W. Cui, J. Pan, D.J. Blackwood, Y. Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Many previous simulations of the plastic deformation in metallic glasses showed that shear banding is the dominant mode accompanied by Voronoi volume continuous generation and softening. In the present work, we report a contrary phenomenon where Voronoi volume recovery is dominant during plastic deformation in CuZr metallic glasses under tension. By creating a notched geometry, the deformation mode of notched samples transits from shear banding to necking due to the introduction of triaxial stress state. With the suppressing of shear banding, a notch strengthening and structure ordering phenomenon together with the recovery of Cu-centered full-icosahedra fraction are also observed. The present work enriches our understanding on the mechanical behavior and deformation mechanism of metallic glasses.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838818339124-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): Ting Wang, Ke Han, Qi Tang, Binggang Zhang, Jicai Feng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Electron beam welding of titanium to copper has been performed with different Cu-V filler metals. Microstructure, mechanical properties and fracture behavior were investigated. Compared with the welded joint without filler metal, the lower V content in Cu75V25 filler metal resulted in the formation of fine Ti-Cu compounds in the interface of TA15 side. Thus, the joint showed a lower tensile strength and fractured along the interfacial reactive layer. When V content is over 34 wt% in the filler metal, the interfacial microstructure near TA15 side formed cellular (Ti,V) solid solution to replace the Ti-Cu compounds, which improved the mechanical properties of the joint. As a result, the joint with Cu66V34 filler metal displayed the highest tensile strength (384 MPa), approaching 82% of that of the copper base metal (BM), and fractured in heat affected zone (HAZ) of copper side, due to the local softening by grains coarsening. In spite of the formed solid solution at the interface, the joint welded with Cu34V66 filler metal containing higher V content, produced amount of pores and unmelted V alloy, which resulted in the decrease of tensile strength down to 55% of that of the copper BM.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838818338969-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 776〈/p〉 〈p〉Author(s): M. Bououdina, A.A. Dakhel, A. Jaafar, J.H. Dai, Y. Song〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉This research work aims to study the effect of co-doping by Al〈sup〉3+〈/sup〉 to increase the electronic charge carrier concentration inversely to Mg〈sup〉2+〈/sup〉. Zn〈sub〉0.97〈/sub〉Gd〈sub〉0.03〈/sub〉O, Zn〈sub〉0.95〈/sub〉Gd〈sub〉0.03〈/sub〉Mg〈sub〉0.02〈/sub〉O, and Zn〈sub〉0.95〈/sub〉Gd〈sub〉0.03〈/sub〉Al〈sub〉0.02〈/sub〉O nanopowders were synthesised by simultaneous thermal co-decomposition of a mixture of cadmium and metal complexes, followed by hydrogenation at 350 and 600 °C. This study aimed at establishing the preparation conditions including hydrogenation that were essential for the creation of room temperature ferromagnetic order starting from the paramagnetic Gd-doped ZnO by using structural and electronic consequences of codoping with ions of Al or Mg. X-ray diffraction analysis confirms total doping of (Gd, Mg and Al) impurities into ZnO host lattice as well as the absence of secondary compounds/oxides in the synthesised solid solutions. The reflectance has been found to be significantly affected upon co-doping and hydrogenation, while the energy band gap decreases slightly; i.e. Eg = 3.23–3.00 eV. Magnetic measurements reveal that all the as-synthesised doped ZnO powders gained paramagnetic behaviour defeating the diamagnetic characteristic of ZnO, due to the presence of Gd ions with an effective magnetic moment in the range 8.04–7.12 μ〈sub〉B〈/sub〉. The hydrogenation in the present work conditions did not change the paramagnetic behaviour except for ZnO:Gd:Al-H, showing a partial a magnetic order overlapping with paramagnetic component, resulting in a coercivity of 170.2 Oe, remanence of 0.550 memu/g, and saturation magnetization of 2.14 memu/g. Therefore, the conditions including hydrogenation that were necessary to create FM ordering were determined.〈/p〉 〈p〉First-principles calculations indicate that the Gd doped ZnO systems own large spin polarized effect due to the interaction between Gd-〈em〉f〈/em〉 and O-〈em〉p〈/em〉 electrons. The Mg and Al dopants can modulate the values of magnetic moments.〈/p〉 〈/div〉 〈/div〉