ALBERT

Description: During quench tests in 2011 variations in resistance of an order of magnitude were found in the diode by-pass circuit of the main LHC magnets. An investigation campaign was started to understand the source, the occurrence and the impact of the high resistances. Many tests were performed offline in the SM18 test facility with a focus on the contact resistance of the diode to heat sink contact and the diode wafer temperature. In 2014 the performance of the diodes and diode leads of the main dipole bypass systems in the LHC was assessed during a high current qualification test. In the test a current cycle similar to a magnet circuit discharge from 11 kA with a time constant of 100 s was performed. Resistances of up to 600 μΩ have been found in the diode leads at intermediate current, but in general the high resistances decrease at higher current levels and no sign of overheating of diodes has been seen and the bypass circuit passed the test. In this report the performance of the dio...

Description: A stochastic background of gravitational waves is expected to arise from a superposition of a large number of unresolved gravitational-wave sources of astrophysical and cosmological origin. It should carry unique signatures from the earliest epochs in the evolution of the Universe, inaccessible to standard astrophysical observations. Direct measurements of the amplitude of this background are therefore of fundamental importance for understanding the evolution of the Universe when it was younger than one minute. Here we report limits on the amplitude of the stochastic gravitational-wave background using the data from a two-year science run of the Laser Interferometer Gravitational-wave Observatory (LIGO). Our result constrains the energy density of the stochastic gravitational-wave background normalized by the critical energy density of the Universe, in the frequency band around 100 Hz, to be 〈6.9 x 10(-6) at 95% confidence. The data rule out models of early Universe evolution with relatively large equation-of-state parameter, as well as cosmic (super)string models with relatively small string tension that are favoured in some string theory models. This search for the stochastic background improves on the indirect limits from Big Bang nucleosynthesis and cosmic microwave background at 100 Hz.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉LIGO Scientific Collaboration & Virgo Collaboration -- Abbott, B P -- Abbott, R -- Acernese, F -- Adhikari, R -- Ajith, P -- Allen, B -- Allen, G -- Alshourbagy, M -- Amin, R S -- Anderson, S B -- Anderson, W G -- Antonucci, F -- Aoudia, S -- Arain, M A -- Araya, M -- Armandula, H -- Armor, P -- Arun, K G -- Aso, Y -- Aston, S -- Astone, P -- Aufmuth, P -- Aulbert, C -- Babak, S -- Baker, P -- Ballardin, G -- Ballmer, S -- Barker, C -- Barker, D -- Barone, F -- Barr, B -- Barriga, P -- Barsotti, L -- Barsuglia, M -- Barton, M A -- Bartos, I -- Bassiri, R -- Bastarrika, M -- Bauer, Th S -- Behnke, B -- Beker, M -- Benacquista, M -- Betzwieser, J -- Beyersdorf, P T -- Bigotta, S -- Bilenko, I A -- Billingsley, G -- Birindelli, S -- Biswas, R -- Bizouard, M A -- Black, E -- Blackburn, J K -- Blackburn, L -- Blair, D -- Bland, B -- Boccara, C -- Bodiya, T P -- Bogue, L -- Bondu, F -- Bonelli, L -- Bork, R -- Boschi, V -- Bose, S -- Bosi, L -- Braccini, S -- Bradaschia, C -- Brady, P R -- Braginsky, V B -- Brand, J F J van den -- Brau, J E -- Bridges, D O -- Brillet, A -- Brinkmann, M -- Brisson, V -- Van Den Broeck, C -- Brooks, A F -- Brown, D A -- Brummit, A -- Brunet, G -- Bullington, A -- Bulten, H J -- Buonanno, A -- Burmeister, O -- Buskulic, D -- Byer, R L -- Cadonati, L -- Cagnoli, G -- Calloni, E -- Camp, J B -- Campagna, E -- Cannizzo, J -- Cannon, K C -- Canuel, B -- Cao, J -- Carbognani, F -- Cardenas, L -- Caride, S -- Castaldi, G -- Caudill, S -- Cavaglia, M -- Cavalier, F -- Cavalieri, R -- Cella, G -- Cepeda, C -- Cesarini, E -- Chalermsongsak, T -- Chalkley, E -- Charlton, P -- Chassande-Mottin, E -- Chatterji, S -- Chelkowski, S -- Chen, Y -- Christensen, N -- Chung, C T Y -- Clark, D -- Clark, J -- Clayton, J H -- Cleva, F -- Coccia, E -- Cokelaer, T -- Colacino, C N -- Colas, J -- Colla, A -- Colombini, M -- Conte, R -- Cook, D -- Corbitt, T R C -- Corda, C -- Cornish, N -- Corsi, A -- Coulon, J-P -- Coward, D -- Coyne, D C -- Creighton, J D E -- Creighton, T D -- Cruise, A M -- Culter, R M -- Cumming, A -- Cunningham, L -- Cuoco, E -- Danilishin, S L -- D'Antonio, S -- Danzmann, K -- Dari, A -- Dattilo, V -- Daudert, B -- Davier, M -- Davies, G -- Daw, E J -- Day, R -- De Rosa, R -- Debra, D -- Degallaix, J -- Del Prete, M -- Dergachev, V -- Desai, S -- Desalvo, R -- Dhurandhar, S -- Di Fiore, L -- Di Lieto, A -- Di Paolo Emilio, M -- Di Virgilio, A -- Diaz, M -- Dietz, A -- Donovan, F -- Dooley, K L -- Doomes, E E -- Drago, M -- Drever, R W P -- Dueck, J -- Duke, I -- Dumas, J-C -- Dwyer, J G -- Echols, C -- Edgar, M -- Effler, A -- Ehrens, P -- Ely, G -- Espinoza, E -- Etzel, T -- Evans, M -- Evans, T -- Fafone, V -- Fairhurst, S -- Faltas, Y -- Fan, Y -- Fazi, D -- Fehrmann, H -- Ferrante, I -- Fidecaro, F -- Finn, L S -- Fiori, I -- Flaminio, R -- Flasch, K -- Foley, S -- Forrest, C -- Fotopoulos, N -- Fournier, J-D -- Franc, J -- Franzen, A -- Frasca, S -- Frasconi, F -- Frede, M -- Frei, M -- Frei, Z -- Freise, A -- Frey, R -- Fricke, T -- Fritschel, P -- Frolov, V V -- Fyffe, M -- Galdi, V -- Gammaitoni, L -- Garofoli, J A -- Garufi, F -- Genin, E -- Gennai, A -- Gholami, I -- Giaime, J A -- Giampanis, S -- Giardina, K D -- Giazotto, A -- Goda, K -- Goetz, E -- Goggin, L M -- Gonzalez, G -- Gorodetsky, M L -- Gobler, S -- Gouaty, R -- Granata, M -- Granata, V -- Grant, A -- Gras, S -- Gray, C -- Gray, M -- Greenhalgh, R J S -- Gretarsson, A M -- Greverie, C -- Grimaldi, F -- Grosso, R -- Grote, H -- Grunewald, S -- Guenther, M -- Guidi, G -- Gustafson, E K -- Gustafson, R -- Hage, B -- Hallam, J M -- Hammer, D -- Hammond, G D -- Hanna, C -- Hanson, J -- Harms, J -- Harry, G M -- Harry, I W -- Harstad, E D -- Haughian, K -- Hayama, K -- Heefner, J -- Heitmann, H -- Hello, P -- Heng, I S -- Heptonstall, A -- Hewitson, M -- Hild, S -- Hirose, E -- Hoak, D -- Hodge, K A -- Holt, K -- Hosken, D J -- Hough, J -- Hoyland, D -- Huet, D -- Hughey, B -- Huttner, S H -- Ingram, D R -- Isogai, T -- Ito, M -- Ivanov, A -- Johnson, B -- Johnson, W W -- Jones, D I -- Jones, G -- Jones, R -- Sancho de la Jordana, L -- Ju, L -- Kalmus, P -- Kalogera, V -- Kandhasamy, S -- Kanner, J -- Kasprzyk, D -- Katsavounidis, E -- Kawabe, K -- Kawamura, S -- Kawazoe, F -- Kells, W -- Keppel, D G -- Khalaidovski, A -- Khalili, F Y -- Khan, R -- Khazanov, E -- King, P -- Kissel, J S -- Klimenko, S -- Kokeyama, K -- Kondrashov, V -- Kopparapu, R -- Koranda, S -- Kozak, D -- Krishnan, B -- Kumar, R -- Kwee, P -- La Penna, P -- Lam, P K -- Landry, M -- Lantz, B -- Laval, M -- Lazzarini, A -- Lei, H -- Lei, M -- Leindecker, N -- Leonor, I -- Leroy, N -- Letendre, N -- Li, C -- Lin, H -- Lindquist, P E -- Littenberg, T B -- Lockerbie, N A -- Lodhia, D -- Longo, M -- Lorenzini, M -- Loriette, V -- Lormand, M -- Losurdo, G -- Lu, P -- Lubinski, M -- Lucianetti, A -- Luck, H -- Machenschalk, B -- Macinnis, M -- Mackowski, J-M -- Mageswaran, M -- Mailand, K -- Majorana, E -- Man, N -- Mandel, I -- Mandic, V -- Mantovani, M -- Marchesoni, F -- Marion, F -- Marka, S -- Marka, Z -- Markosyan, A -- Markowitz, J -- Maros, E -- Marque, J -- Martelli, F -- Martin, I W -- Martin, R M -- Marx, J N -- Mason, K -- Masserot, A -- Matichard, F -- Matone, L -- Matzner, R A -- Mavalvala, N -- McCarthy, R -- McClelland, D E -- McGuire, S C -- McHugh, M -- McIntyre, G -- McKechan, D J A -- McKenzie, K -- Mehmet, M -- Melatos, A -- Melissinos, A C -- Mendell, G -- Menendez, D F -- Menzinger, F -- Mercer, R A -- Meshkov, S -- Messenger, C -- Meyer, M S -- Michel, C -- Milano, L -- Miller, J -- Minelli, J -- Minenkov, Y -- Mino, Y -- Mitrofanov, V P -- Mitselmakher, G -- Mittleman, R -- Miyakawa, O -- Moe, B -- Mohan, M -- Mohanty, S D -- Mohapatra, S R P -- Moreau, J -- Moreno, G -- Morgado, N -- Morgia, A -- Morioka, T -- Mors, K -- Mosca, S -- Mossavi, K -- Mours, B -- Mowlowry, C -- Mueller, G -- Muhammad, D -- Muhlen, H Zur -- Mukherjee, S -- Mukhopadhyay, H -- Mullavey, A -- Muller-Ebhardt, H -- Munch, J -- Murray, P G -- Myers, E -- Myers, J -- Nash, T -- Nelson, J -- Neri, I -- Newton, G -- Nishizawa, A -- Nocera, F -- Numata, K -- Ochsner, E -- O'Dell, J -- Ogin, G H -- O'Reilly, B -- O'Shaughnessy, R -- Ottaway, D J -- Ottens, R S -- Overmier, H -- Owen, B J -- Pagliaroli, G -- Palomba, C -- Pan, Y -- Pankow, C -- Paoletti, F -- Papa, M A -- Parameshwaraiah, V -- Pardi, S -- Pasqualetti, A -- Passaquieti, R -- Passuello, D -- Patel, P -- Pedraza, M -- Penn, S -- Perreca, A -- Persichetti, G -- Pichot, M -- Piergiovanni, F -- Pierro, V -- Pinard, L -- Pinto, I M -- Pitkin, M -- Pletsch, H J -- Plissi, M V -- Poggiani, R -- Postiglione, F -- Principe, M -- Prix, R -- Prodi, G A -- Prokhorov, L -- Punken, O -- Punturo, M -- Puppo, P -- Putten, S van der -- Quetschke, V -- Raab, F J -- Rabaste, O -- Rabeling, D S -- Radkins, H -- Raffai, P -- Raics, Z -- Rainer, N -- Rakhmanov, M -- Rapagnani, P -- Raymond, V -- Re, V -- Reed, C M -- Reed, T -- Regimbau, T -- Rehbein, H -- Reid, S -- Reitze, D H -- Ricci, F -- Riesen, R -- Riles, K -- Rivera, B -- Roberts, P -- Robertson, N A -- Robinet, F -- Robinson, C -- Robinson, E L -- Rocchi, A -- Roddy, S -- Rolland, L -- Rollins, J -- Romano, J D -- Romano, R -- Romie, J H -- Rover, C -- Rowan, S -- Rudiger, A -- Ruggi, P -- Russell, P -- Ryan, K -- Sakata, S -- Salemi, F -- Sandberg, V -- Sannibale, V -- Santamaria, L -- Saraf, S -- Sarin, P -- Sassolas, B -- Sathyaprakash, B S -- Sato, S -- Satterthwaite, M -- Saulson, P R -- Savage, R -- Savov, P -- Scanlan, M -- Schilling, R -- Schnabel, R -- Schofield, R -- Schulz, B -- Schutz, B F -- Schwinberg, P -- Scott, J -- Scott, S M -- Searle, A C -- Sears, B -- Seifert, F -- Sellers, D -- Sengupta, A S -- Sentenac, D -- Sergeev, A -- Shapiro, B -- Shawhan, P -- Shoemaker, D H -- Sibley, A -- Siemens, X -- Sigg, D -- Sinha, S -- Sintes, A M -- Slagmolen, B J J -- Slutsky, J -- van der Sluys, M V -- Smith, J R -- Smith, M R -- Smith, N D -- Somiya, K -- Sorazu, B -- Stein, A -- Stein, L C -- Steplewski, S -- Stochino, A -- Stone, R -- Strain, K A -- Strigin, S -- Stroeer, A -- Sturani, R -- Stuver, A L -- Summerscales, T Z -- Sun, K-X -- Sung, M -- Sutton, P J -- Swinkels, B L -- Szokoly, G P -- Talukder, D -- Tang, L -- Tanner, D B -- Tarabrin, S P -- Taylor, J R -- Taylor, R -- Terenzi, R -- Thacker, J -- Thorne, K A -- Thorne, K S -- Thuring, A -- Tokmakov, K V -- Toncelli, A -- Tonelli, M -- Torres, C -- Torrie, C -- Tournefier, E -- Travasso, F -- Traylor, G -- Trias, M -- Trummer, J -- Ugolini, D -- Ulmen, J -- Urbanek, K -- Vahlbruch, H -- Vajente, G -- Vallisneri, M -- Vass, S -- Vaulin, R -- Vavoulidis, M -- Vecchio, A -- Vedovato, G -- van Veggel, A A -- Veitch, J -- Veitch, P -- Veltkamp, C -- Verkindt, D -- Vetrano, F -- Vicere, A -- Villar, A -- Vinet, J-Y -- Vocca, H -- Vorvick, C -- Vyachanin, S P -- Waldman, S J -- Wallace, L -- Ward, H -- Ward, R L -- Was, M -- Weidner, A -- Weinert, M -- Weinstein, A J -- Weiss, R -- Wen, L -- Wen, S -- Wette, K -- Whelan, J T -- Whitcomb, S E -- Whiting, B F -- Wilkinson, C -- Willems, P A -- Williams, H R -- Williams, L -- Willke, B -- Wilmut, I -- Winkelmann, L -- Winkler, W -- Wipf, C C -- Wiseman, A G -- Woan, G -- Wooley, R -- Worden, J -- Wu, W -- Yakushin, I -- Yamamoto, H -- Yan, Z -- Yoshida, S -- Yvert, M -- Zanolin, M -- Zhang, J -- Zhang, L -- Zhao, C -- Zotov, N -- Zucker, M E -- Zweizig, J -- England -- Nature. 2009 Aug 20;460(7258):990-4. doi: 10.1038/nature08278.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Lists of participants and their affiliations appear at the end of the paper.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19693079" target="_blank"〉PubMed〈/a〉

Description: Measurement of the Earth tides with a MEMS gravimeter Nature 531, 7596 (2016). doi:10.1038/nature17397 Authors: R. P. Middlemiss, A. Samarelli, D. J. Paul, J. Hough, S. Rowan & G. D. Hammond The ability to measure tiny variations in the local gravitational acceleration allows, besides other applications, the detection of hidden hydrocarbon reserves, magma build-up before volcanic eruptions, and subterranean tunnels. Several technologies are available that achieve the sensitivities required for such applications (tens of microgal per hertz1/2): free-fall gravimeters, spring-based gravimeters, superconducting gravimeters, and atom interferometers. All of these devices can observe the Earth tides: the elastic deformation of the Earth’s crust as a result of tidal forces. This is a universally predictable gravitational signal that requires both high sensitivity and high stability over timescales of several days to measure. All present gravimeters, however, have limitations of high cost (more than 100,000 US dollars) and high mass (more than 8 kilograms). Here we present a microelectromechanical system (MEMS) device with a sensitivity of 40 microgal per hertz1/2 only a few cubic centimetres in size. We use it to measure the Earth tides, revealing the long-term stability of our instrument compared to any other MEMS device. MEMS accelerometers—found in most smart phones—can be mass-produced remarkably cheaply, but none are stable enough to be called a gravimeter. Our device has thus made the transition from accelerometer to gravimeter. The small size and low cost of this MEMS gravimeter suggests many applications in gravity mapping. For example, it could be mounted on a drone instead of low-flying aircraft for distributed land surveying and exploration, deployed to monitor volcanoes, or built into multi-pixel density-contrast imaging arrays.

Description: Author(s): R. Birney, J. Steinlechner, Z. Tornasi, S. MacFoy, D. Vine, A. S. Bell, D. Gibson, J. Hough, S. Rowan, P. Sortais, S. Sproules, S. Tait, I. W. Martin, and S. Reid Amorphous silicon has ideal properties for many applications in fundamental research and industry. However, the optical absorption is often unacceptably high, particularly for gravitational-wave detection. We report a novel ion-beam deposition method for fabricating amorphous silicon with unpreceden... [Phys. Rev. Lett. 121, 191101] Published Tue Nov 06, 2018

Description: Author(s): J. Steinlechner, I. W. Martin, A. S. Bell, J. Hough, M. Fletcher, P. G. Murray, R. Robie, S. Rowan, and R. Schnabel Thermal noise of highly reflective mirror coatings is a major limit to the sensitivity of many precision laser experiments with strict requirements such as low optical absorption. Here, we investigate amorphous silicon and silicon nitride as an alternative to the currently used combination of coatin... [Phys. Rev. Lett. 120, 263602] Published Fri Jun 29, 2018

Description: Author(s): K. Haughian, A. A. van Veggel, L. Cunningham, J. Hough, P. G. Murray, S. Reid, and S. Rowan Hydroxide catalysis bonds are used in the aLIGO gravitational wave detectors and are an essential technology within the mirror suspensions that allowed detector sensitivities to be reached, which enabled the first direct detections of gravitational waves. Methods aimed at further improving hydroxide... [Phys. Rev. D 96, 042003] Published Fri Aug 25, 2017

Description: The ability to measure tiny variations in the local gravitational acceleration allows, besides other applications, the detection of hidden hydrocarbon reserves, magma build-up before volcanic eruptions, and subterranean tunnels. Several technologies are available that achieve the sensitivities required for such applications (tens of microgal per hertz(1/2)): free-fall gravimeters, spring-based gravimeters, superconducting gravimeters, and atom interferometers. All of these devices can observe the Earth tides: the elastic deformation of the Earth's crust as a result of tidal forces. This is a universally predictable gravitational signal that requires both high sensitivity and high stability over timescales of several days to measure. All present gravimeters, however, have limitations of high cost (more than 100,000 US dollars) and high mass (more than 8 kilograms). Here we present a microelectromechanical system (MEMS) device with a sensitivity of 40 microgal per hertz(1/2) only a few cubic centimetres in size. We use it to measure the Earth tides, revealing the long-term stability of our instrument compared to any other MEMS device. MEMS accelerometers--found in most smart phones--can be mass-produced remarkably cheaply, but none are stable enough to be called a gravimeter. Our device has thus made the transition from accelerometer to gravimeter. The small size and low cost of this MEMS gravimeter suggests many applications in gravity mapping. For example, it could be mounted on a drone instead of low-flying aircraft for distributed land surveying and exploration, deployed to monitor volcanoes, or built into multi-pixel density-contrast imaging arrays.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Middlemiss, R P -- Samarelli, A -- Paul, D J -- Hough, J -- Rowan, S -- Hammond, G D -- England -- Nature. 2016 Mar 31;531(7596):614-7. doi: 10.1038/nature17397.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Scottish Universities Physics Alliance (SUPA), University of Glasgow, School of Physics and Astronomy, Kelvin Building, University Avenue, Glasgow G12 8QQ, UK. ; University of Glasgow, School of Engineering, Rankine Building, Oakfield Avenue, Glasgow G12 8LT, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/27029276" target="_blank"〉PubMed〈/a〉

Description: Author(s): K. Haughian, D. Chen, L. Cunningham, G. Hofmann, J. Hough, P. G. Murray, R. Nawrodt, S. Rowan, A. A. van Veggel, and K. Yamamoto Hydroxide catalysis bonds are low mechanical loss joints which are used in the fused silica mirror suspensions of current room temperature interferometric gravitational wave detectors, one of the techniques which was essential to allow the recent detection of gravitational radiation by LIGO. More se… [Phys. Rev. D 94, 082003] Published Wed Oct 12, 2016

Description: Crutzen and Stoermer’s (2000) naming of the ‘Anthropocene’ has provoked lively debate across the physical and social sciences, but, while the term is gradually gaining acceptance as the signifier of the current geological epoch, it remains little more than a roughly defined place-holder for an era characterized by environmental and social uncertainty. The term invites deeper considerations of its meaning, significance, and consequences for thought and politics. For this Forum, we invited five scholars to reflect on how the Anthropocene poses challenges to the structures and habits of geography, politics, and their guiding concepts. The resulting essays piece together an agenda for geographic thought – and political engagement – in this emerging epoch. Collectively, they suggest that geography, as a discipline, is particularly well suited to address the conceptual challenges presented by the Anthropocene.

Description: It is widely believed that the last glaciers in the British Isles disappeared at the end of the Younger Dryas stadial (12.9–11.7 cal. kyr BP). Here, we use a glacier–climate model driven by data from local weather stations to show for the first time that glaciers developed during the Little Ice Age (LIA) in the Cairngorm Mountains. Our model is forced from contemporary conditions by a realistic difference in mean annual air temperature of –1.5°C and an increase in annual precipitation of 10%, and confirmed by sensitivity analyses. These results are supported by the presence of small boulder moraines well within Younger Dryas ice limits, and by a dating programme on a moraine in one cirque. As a result, we argue that the last glaciers in the Cairngorm Mountains (and perhaps elsewhere in upland Britain) existed in the LIA within the last few hundred years, rather than during the Younger Dryas.