ALBERT

Notes: We present the design and the results of the evaluation of a fast, low noise, charge preamplifier. This device uses commercial circuits; the advantages over classical circuits based on transistors are presented. These include short development time, high reliability and reproducibility, and easy maintenance. The amplifier has been tested with a position sensitive multiwire proportional counter with a readout system based on delay lines. With an input impedance of 50 Ω, we have obtained a signal to noise ratio better than 40 dB, a gain of 0.42 μV per electron, a pulse rise time of 9.4 ns, and a total pulse duration lower than 120 ns. These values allow detector data acquisition rates in excess of 1 MHz, and a spatial resolution better than 300 μm. © 2002 American Institute of Physics.

Notes: A laser-based technique for measuring the curvature of a multilayer/substrate couple is described. Unlike most wafer curvature systems, the instrument described measures the local curvature of the multilayer/substrate couple, correcting for the local topography of the substrate, rather than measuring changes in the average curvature of the multilayer/substrate couple. The apparatus has been designed specifically to perform biaxial zero-creep measurements at elevated temperatures in vacuum. It can also be used to examine the development of biaxial stresses during thermal cycling of thin films deposited on substrates. © 2002 American Institute of Physics.

Notes: We have succeeded in developing a new high-pressure cell designed for measuring the absolute value of the electrical resistivity in magnetic fields at low temperatures. This pressure cell, based on a technique using modified Bridgman anvils with a Teflon capsule, can generate nearly hydrostatic pressure at least up to 6 GPa. The most important feature of this pressure cell is its compact body which can be easily combined with a dilution refrigerator in a superconducting magnet. One of its applications is for precise magneto-transport measurements under nearly hydrostatic pressure, which is demonstrated by the investigation into the pressure-induced superconducting state of the spin-ladder Sr14−xCaxCu24O41 (x=12) single crystal. © 2002 American Institute of Physics.

Notes: For milling over large areas there is need for broad ion beam sources with a uniform etch rate profile. Currently uniform ion beam density is obtained in the central portion of the ion source by manipulating the grids and the magnets in the ion source. We have designed and implemented specially shaped hard masks to a rotating substrate holder. This mask is able to transform the Gaussian etch rate profile of a 150-mm-diam Oxford ion source to a flat profile. The flat profile decreases the etch rate in the central portion while maintaining the same etch rate along the edge. The deviation in the ion beam etch rate is within 5% in the flat region. © 2002 American Institute of Physics.

Notes: We report an experimental technique provided to study the full three-dimensional velocity distribution of state-selected products of a chemical process. Time-of-flight mass spectroscopy and resonance enhanced multiphoton ionization combined with a position sensitive detector (delay-line anode) are employed. The technique has a space resolution of 0.4 mm, a time resolution better than 1 ns, and it provides the possibility to detect several products with a minimal difference between arrival times of 17 ns. One major achievement of the new technique is the possibility to determine the full three-dimensional momentum vectors of a chemical reaction product. This is especially valuable for cases where no symmetry is considered in the process. Second, the high sensitivity of the method allowing to observe single ions enables us to study physical and chemical processes at extremely low densities. Three methods for measuring the temperature of a molecular beam with the technique are demonstrated. A novel result of the present work is the study of angular distribution of NO ions due to electron recoil in the ionization of NO(A 2Σ+). Finally the advantages of the method are examined by studying the speed distributions of Cl atoms in the photolysis of Cl2 at 355 nm. © 2002 American Institute of Physics.

Notes: A new development of electrostatic lenses for ion and/or electron trajectory focusing has been implemented in a double velocity spectrometer which combines time of flight resolved coincidence and imaging techniques using fast position sensitive detectors. Ions and electrons produced by photoionization are extracted from the interaction region by a unique uniform electrostatic field, while the electrostatic lenses create a nonuniform field outside the extraction region. The space focusing reducing the effect of the finite dimensions of the interaction region on one side, and the global bending of the ion and/or electron trajectories preserving the time of flight information on the other side, enable a significant improvement of the resolution of the three measured velocity components for each particle. Such a device is particularly well adapted for the study of vector correlations in dissociative photoionization of simple molecules in the vacuum ultraviolet photon energy range. The gain achieved in the energy resolution of the processes by ion–electron kinetic energy correlation, as well as in the polar and azimuthal angle resolution in the I(θe,φe) molecular frame photoelectron angular distributions, is illustrated on the example of dissociative photoionization of the NO molecule. © 2002 American Institute of Physics.

Notes: Results are presented on the maximum current density obtained in pulsed (2 μs) contact ionization sources that utilize potassium and cesium atoms on porous tungsten substrates. Maximum values of 89 and 48 mA/cm2 for K+ and Cs+, respectively, were obtained in space charge limited mode for the source geometry used. Similar results were observed for potassium aluminosilicate (K20⋅Al2O3⋅4SiO2) sources. Neutral emission rates were measured in the temperature range of interest to heavy ion fusion (1000–1150 °C). Evidence is presented regarding a diffusion-limited flow of alkali atoms towards the emitting surface, which would be a determining factor in the source lifetime. © 2002 American Institute of Physics.

Notes: Characteristics of an ion beam surface modification system with a linear ion source are described in this article. The linear ion source is principally based on an anode layer thruster, which is generally referred to as "closed drift thruster." The linear ion source has a slit type racetrack-shape extraction geometry. The spatial current distribution of the extracted ion beam has, therefore, a racetrack shape. Experiments were carried out for the discharge voltages ranging from 500 to 1500 V and ion doses ranging from 7.3×1013 to 8.2×1014 ions/cm2, using three kinds of ion species, namely, oxygen, nitrogen, and argon. Ion beam current density was uniform in the direction of the straight part of the extraction slit. Metalization of the surface modified polymers was also performed. To study the improvement of the adhesion of the metal films to the polymers, the peel-off tests were carried out on ion-irradiated polyimide-copper films. The results indicated that adhesion strength between polyimide and copper was improved as a result of the surface modification by the linear ion source. © 2002 American Institute of Physics.

Notes: This work is directed towards substantially improving the sensitivity of an inductively coupled plasma mass spectrometer (ICP-MS). Ions produced in the ICP at atmospheric pressure have been extracted with comparatively high current densities. The conventional approach to ion extraction, based on a skimmed molecular beam, has been abandoned, and a high extraction field arrangement has been adopted. Although the new approach is not optimized, current densities more than 180 times greater than that of a conventional interface have been extracted and analyte sensitivities ∼10–100× greater than those reported previously for quadrupole ICP-MS have been measured. © 2002 American Institute of Physics.

Notes: The ISIS ion source is a surface plasma ion source of the Penning type, and routinely produces 35 mA of H− ions during a 200 μs pulse at 50 Hz for uninterrupted periods of up to 50 days. However, because of the constant demands on ISIS from the neutron user community, very little ion source development has ever been possible. It is now necessary to produce sources with enhanced performances for next generation projects such as the European spallation source. Hence a dedicated ion source development rig (ISDR) has been constructed at Rutherford Appleton Laboratory to fully characterize the ISIS ion source and then facilitate appropriate development work. The ISDR has been designed to replicate the beam transport configurations on both the present ISIS preinjector and the proposed ISIS radio frequency quadrupole, while providing additional beam diagnostics equipment. The commissioning of the ISDR will be described, and initial results presented, along with future development plans. © 2002 American Institute of Physics.

Notes: A polarization analyzer has been designed for soft x-ray resonant diffraction experiments at the S K edge. The Bragg angle of graphite (0001) at the S K edge is 48°, which makes it perfectly suited as polarization analyzer. Two graphite (0001) crystals (12×12×2 mm3) are mounted on small tangent-arm driven spring loaded stages with their diffraction planes in the horizontal and vertical plane for σ and π analysis of polarized x rays. The diffracted x rays are detected by small peltier cooled Si detectors with dimensions 1×12 mm2 with the longer dimension in the direction of diffraction, so that the detector can remain fixed. These two polarization analyzers and an additional detector for the directly diffracted beam are mounted on a stage, so that the polarization of the diffracted x rays can be determined just by moving the appropriate analyzer into the beam. The tangent arm and the detector allow us to scan ±50 eV around the S K edge. This setup avoids mounting of the polarization analyzer on a rotation stage, whose axis has to be aligned with the diffracted beam. The tangent-arm is driven by motorized micrometers, which are equipped with encoders to obtain an angular resolution of 0.001°. © 2002 American Institute of Physics.

Notes: The preliminary instrumentation for diffraction dipole beamline for a 3 GeV synchrotron light source called CANDLE—Center for the Advancement of Natural Discoveries using Light Emission, in the Republic of Armenia is given. The beamlines are expected to be used for both white and, monochromatic hard x-ray radiation ranging from 5 to 30 keV. One of the topics of study—material science research—that can be conducted at the end station is described, which includes the white topography, phase contrast imaging, interferometry, roentgenography, fluorescence analysis, and diffraction optics. © 2002 American Institute of Physics.

Notes: A far-infrared beamline has been implemented on port 031 of the Aladdin Storage Ring. Port 031 has been designed to capture the edge radiation produced by the fringe field of a bending magnet rather than normal bending magnet radiation. Calculations indicate that in cases where the aperture is limited edge radiation provides higher flux than bending magnets, particularly at the longer wavelengths. The far-infrared (IR) beamline shares this port with a mid-IR microscope beamline and uses the same optics to collect and collimate the light. To install the far-IR beamline, a special mirror was designed to deflect light to the purged bench and microscopes or to move out of the light path and allow the light to continue to the far-IR beamline. The vacuum bench employs a Thermo Nicolet interferometer with a solid substrate beamsplitter modified for use under rough vacuum. The light from the interferometer is focused through CsI windows on a sample in an ultrahigh vacuum chamber. The specular reflected light from the sample is collected by an elliptical mirror and focused onto a bolometer detector. The details of the beamline will be discussed as well as the first experimental results. © 2002 American Institute of Physics.

Notes: Toroidal mirrors can be used to efficiently focus synchrotron radiation for magnifications near 1. At the Pacific Northwest Consortium-Collaborative Access Team (PNC-CAT) insertion device beamline, a toroidal mirror is used to focus the entire undulator beam to a spot size of 400(H)×100(V) μm2. For large demagnifications, Kirkpatrick–Baez (KB) mirrors are a good choice. Spot sizes down to 1 μm have been achieved at PNC-CAT. However, these mirrors only collect a fraction of the undulator beam, and result in a highly divergent beam with a short working distance. To achieve an intermediate beam size with less divergence, the toroidal and KB mirrors can be combined. The toroidal mirror reduces the beam to match the entrance aperture of the KB mirrors. This combination can provide beam sizes below 100 μm while collecting the entire undulator beam and providing a convenient working distance. Thus, the beam size, working distance, and divergence can be tailored to the needs of the experiment. © 2002 American Institute of Physics.

Notes: An evaluation system capable of measuring the wavelength and angular characteristics of the absolute reflectivity (or diffraction efficiency) of soft x-ray optical elements has been designed and constructed. The system was installed on a beamline (BL-11) of the AURORA, a superconducting compact storage ring, at the Synchrotron Radiation Center, Ritsumeikan University. To cover a wavelength range of 0.5 nm〈λ〈25 nm, this system incorporates two types of Monk–Gillieson monochromators. One is a conventional type equipped with three varied-line-spacing gratings, allowing a choice of two included angles. The other is a new type that employs a scanning mechanism based on surface normal rotation. The outline of the system and some preliminary experimental data obtained in the course of test runs are described. © 2002 American Institute of Physics.

Notes: Beamline 2-BM at the Advanced Photon Source has been fully commissioned for a range of x-ray microtechniques including micromachining, microtomography, and microcharacterization by scattering and fluorescence. The beamline has been designed and constructed to provide a highly collimated beam with great flexibility in tuning the energy bandpass. To achieve this, the beamline incorporates two mirrors, filters, and two monochromators allowing selection of energy in the range of 3–33 keV with a bandpass in the range of 1–1000 eV. The endstation includes precision instrumentation for deep x-ray lithography, x-ray microtomography, x-ray imaging, x-ray optics characterization, and the development of techniques for high-throughput x-ray microcharacterization of libraries of samples. The various experimental systems are controlled and integrated in the station to allow for the flexibility of techniques, while improving efficiency of use. We describe in detail the beamline design, capabilities, and endstation instrumentation. © 2002 American Institute of Physics.

Notes: We propose here a deep multilayer grating with an adjustable bandpass as an alternative dispersive element for use in x-ray spectroscopy and monochromatization. When making a multilayer grating, we remove part of the reflecting planes of a multilayer, allowing radiation to penetrate deeper. Since the resolution, or the bandpass, is reciprocally proportional to the penetration depth, we improve the resolution and reduce the bandpass of a simple multilayer mirror without affecting the reflectivity. By changing the grating land/period ratio, the amount of the removed material can be continuously varied and, thus, the extinction depth and the bandpass, or resolution, can be continuously varied. In this way we can find an optimum between required resolution and flux for a particular application. © 2002 American Institute of Physics.

Notes: A high-resolution, high-intensity 3 m normal-incidence-monochromator beamline at the J. Bennett Johnston Sr. Center for Advanced Microstructures and Devices is described. The beamline was designed primarily for high-resolution photoelectron spectroscopy utilizing a Scienta electron analyzer, which is permanently placed as an endstation at the beamline. In order to expand utilization of the beamline, an additional beamline tail also has been designed. Optical design of the beamline and preliminary performance results are discussed. © 2002 American Institute of Physics.

Notes: An insertion device beamline at the Advanced Photon Source had received a second insertion device "undulator A" and consequently needed an upgrade of the optics. The decision to use diamond optics required a mechanical modification of the double crystal monochromator and its crystal alignment stages. Specifications for the tilt alignment accuracy are developed. A crystal alignment stage with independent tilt and translation is described. A new crystal holder was developed, which reduces the temperature of the diamond crystal by over 100 °C and allows for strain-free mounting. © 2002 American Institute of Physics.

Notes: Planned fourth generation sources, i.e., XFELs, motivate the study of dynamical diffraction effects in the interesting regime where pulse durations (femtoseconds) become comparable to or shorter than extinction lengths (microns). The transient, time-dependent diffracted intensities arising from incident delta-function impulses are calculated for Bragg and Laue geometries, examining both reflected and transmitted beams. Furthermore, the alteration of an XFEL pulse's spiky temporal structure as it passes through single- and double-crystal monochromators is discussed for both low- and high-order reflections. © 2002 American Institute of Physics.

Notes: Performance tests were carried out on a varied line-spacing plane grating monochromator at BL27SU of SPring-8 in the higher energy region using photoabsorption spectra of gas and solid samples and photoelectron spectra of Xe 5p3/2. A flux of 1×1011 photons/s/100 mA/0.02% b.w. was achieved at 2 keV. The photon flux steeply decreased above 2 keV to 5×109 photons/s/100 mA/0.02% b.w. at 2.8 keV. © 2002 American Institute of Physics.

Notes: A commercial Nicolet Magna-IR series rapid-scan Michelson Fourier transform infrared was installed in a vacuum housing and integrated into the U4IR beamline at the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory. The frequency reference laser was mounted outside the vacuum, but the moving mirror mechanism and the dynamic alignment system for the fixed mirror were in a vacuum. The performance of the instrument was measured in the usual way by measuring the repeatability of data collected under specific conditions of aperture, resolution, and mirror scanning velocity. We briefly discuss the beamline design, to put the interferometer in context, then present signal to noise data which we discuss in terms of both instrument performance and also storage ring beam stability. Under optimal conditions, the instrument has a reproducibility of 0.01% in 1 min of measuring time at a resolution of 2 cm−1, over a range from 100–3000 cm−1. © 2002 American Institute of Physics.

Notes: We have built an end station for x-ray magnetic circular dichroism (XMCD) measurements on proteins and paramagnetic compounds. Our current setup reaches a base temperature of 2.6 K and magnetic fields up to 6 T and is operated at beamline 4.02 of the Advanced Light Source. In this article we discuss magnetic field and low temperature requirements needed to perform XMCD experiments on magnetically saturated samples. For a typical 3d transition metal paramagnetic system we find that fields above 4 T at a temperature of 2.6 K saturate the magnetization of the sample to more than 80%. We discuss principal considerations for a setup operated at low temperatures on a synchrotron and show that infrared heat shielding is unavoidable to obtain the base temperature at the sample. We show first experimental results from the vanadium (IV) compound VOSO4X[H2O]. © 2002 American Institute of Physics.

Notes: Recent success of coherent elastic [Nuclear Resonant Scattering of Synchrotron Radiation, Part A edited by E. Gerdau and H. de Woard (Baltzer Science, 2000), Hyperfine Interact. 123/124, Chap. 4] and incoherent inelastic (Hyperfine Interact. 123/124, Chap. 5) Mössbauer scattering of synchrotron radiation (SR) in investigations of very delicate properties of the condensed matter also makes it urgent to perform experiments on coherent inelastic Mössbauer scattering (CIMS) of synchrotron radiation (the common meaning of the term CIMS is coherent inelastic Mössbauer scattering accompanied by creation or annihilation of phonons in the crystal lattice, i.e., by very low energy losses of SR quanta). However up to now there were no publications on experimental observation of CIMS so there is a need in theoretical investigations to reveal the most favorable conditions for CIMS observation. The theory of CIMS is presented below and applied to specific processes of CIMS such as forward scattering, scattering at grazing incidence angles, and scattering via a cascade of Mössbauer transitions. It is shown that the phase matching (between the incident and scattered beam) is very important for the angular and frequency distribution in CIMS and processes where phase matching can be reached, which the best candidates for CIMS experimental investigations. The performed analysis shows that because of the phase matching demands the forward CIMS is suppressed significantly in comparison with the coherent elastic Mössbauer scattering [V. A. Belyakov, JETP Lett. 67, 8 (1998)] and more favorable for observation is CIMS at a nonzero scattering angle. Some examples of CIMS specific geometries are discussed. In particular, it is shown that for the grazing CIMS at isotope interface (a plane interface between regions with different abundance of the Mössbauer isotope) there is enhancement of CIMS at the critical angle of total reflection and suppression of CIMS at angles below the critical one [V. A. Belyakov, JETP Lett. 68, 287 (1998); V. A. Belyakov and S. V. Semenov, JETP 90, 290 (2000)]. Another possibility of CIMS in a more general meaning of the term is Mössbauer scattering of SR via a cascade of Mössbauer transitions (CIMC) which is connected with huge losses of energy by SR quanta in the process [V. A. Belyakov and Yu. M. Aivazian, Nucl. Instrum. Methods, Phys. Res. A 359, 190 (1995); 448, 222 (2000)]. Analysis of CIMC for the two transitions cascade in Fe57 and the corresponding calculations are presented. Optimal conditions of experimental observation for various cases of CIMS are discussed. © 2002 American Institute of Physics.

Notes: The piezo-x-ray absorption spectroscopy technique is a novel tool for time-resolved x-ray absorption spectroscopy in the hard x-ray range. It makes use of piezo tilt tables mounted below the crystals in a double crystal or channel cut crystal monochromator. Repetitive energy scans are performed by applying an oscillatory high voltage to the piezo translators of the tilt tables. Currently, this allows one to scan an energy range of several hundred eV in the hard x-ray range with repetition frequencies of typically 10 Hz. The capability to record full extended x-ray absorption fine structure spectra on a subsecond time scale is demonstrated. © 2002 American Institute of Physics.

Notes: Small-angle scattering is widely used for measuring materials microstructure in the 1–100 nm size range. Ultrasmall-angle x-ray scattering (USAXS), typically achieved through crystal collimation, extends this size range to include features over 1 μm in size. This article reports on USAXS on the UNICAT beam line 33-ID at the Advanced Photon Source. The instrument makes use of a six-reflection crystal pair as a collimator and another six-reflection crystal pair as an analyzer. First principle absolute calibration and a broad scattering vector range make this a very effective instrument, limited only by the fact that the measurement of anisotropic microstructures is excluded due to slit smearing from the crystal collimation. This limitation has recently been removed by adding a horizontally reflecting crystal before and another after the sample. This creates a USAXS instrument with collimation in two orthogonal directions. We call this configuration effective pinhole USAXS. Now, anisotropic materials are probed using 9–17 keV photons in the same physically-relevant (from 50 nm to over 1 μm) microstructural size range as that available for materials which scatter isotropically. © 2002 American Institute of Physics.

Notes: The current status of the Louisiana State University Center for Advanced Microstructures and Devices electron storage ring, beamlines, and the scientific program are described. © 2002 American Institute of Physics.

Notes: Heavy ion beam inertial fusion driver concepts depend on the availability and performance of high-brightness high-current ion sources. Surface ionization sources have relatively low current density but high brightness because of the low temperature of the emitted ions. We have measured the beam profiles at the exit of the injector diode, and compared the measured profiles with EGUN and WARP-3D predictions. Spherical aberrations are significant in this large aspect ratio diode. We discuss the measured and calculated beam size and beam profiles, the effect of aberrations, quality of vacuum, and secondary electron distributions on the beam profile. © 2002 American Institute of Physics.

Notes: In contrast to the multiaperture–multigrid concept of the International Thermonuclear Experimental Reactor (ITER) injector reference design in which D− acceleration to 40 A, 1 MeV is achieved through seven grids containing 1280 apertures each, the European SINGAP (single gap–single aperture) concept proposes acceleration of 1280 preaccelerated (20–50 keV) beamlets to 1 MeV in a single step. During acceleration the beamlets are merged into 16 groups of 80 beamlets. These 16 so-called hyperbeamlets then emerge from an exit grid containing only 16 very large apertures. This concept is expected to reduce cost and increase the tolerance to mechanical errors and stray magnetic fields. The SINGAP physics is described here. The SINGAP beam optics is calculated to provide good beam transmission (86%) to the ITER. © 2002 American Institute of Physics.

Notes: Negative H− ion beams produced by a tandem-type H− ion source have good beam optics with a typical beam divergence angle of less than 5 mrad. However, the physical reason has not yet been made clear. To clarify the mechanism, we investigate a velocity distribution of negative ions at the extraction holes by a three-dimensional (3D) Monte Carlo transport code. In this code, surface-produced H− ion trajectories are calculated by numerically solving the 3D equation of motion for H− ions. The energy of the H− ions is relaxed through Coulomb collision with the background plasma (H+ ions), which has a low temperature of ∼1 eV in the tandem-type H− ion source. Therefore, energy relaxation by Coulomb collision plays an important role in good beam optics. © 2002 American Institute of Physics.

Notes: The Large Helical Device-Neutral Beam Injector (LHD-NBI) system uses 40 A×180 keV (10 s) negative hydrogen ion sources. Three studies of the H− ion source are reported, i.e., conditioned status, co-accelerated electron beam component, and weight loss of tungsten filaments. Total injection numbers through experimental cycles sum up to ∼8000 shots with four ion sources on two beam lines. Injection power reached a maximum of 5.2 MW. The maximum energy achieved was 171 keV. A pulse length up to 80 s was reached with 0.5 MW. Electron fraction in the accelerated H− beam was evaluated by measuring the heat load on the electron beam dump. Total fraction of the power in the electron beam component deposited on the dump was evaluated to be 1.5%–6% with up to ∼1 Pa of H2. Stripped electrons which were produced inside acceleration gap comprised the majority compared to electrons extracted from source plasma. The weight loss of tungsten filament was 0.01–0.103 mgr/shot/filament. The total loss was ∼0.5% after ∼6500 shots. They were evaporated and a bit spotted. Distribution of the loss over the filament location in the plasma source and over the filament length along tungsten wire corresponded to the nonuniformity of the discharge plasma and H− ions. © 2002 American Institute of Physics.

Notes: The negative ion based neutral beam injector heating system for JT-60U has contributed to core plasma heating and noninductive current drive experiments on JT-60U. For increasing further the beam power and beam pulse duration, the serious issue is improvement of source plasma nonuniformity in the ion source. Various countermeasures have been devised to solve the nonuniformity. The first is to adjust the spatial distribution of the arc discharge through regulating the arc current limiting resistors to be connected in series to each of the filament groups. The second is to change the arc discharge mode through controlling the filament temperature. These measures have been found to be very effective. © 2002 American Institute of Physics.

Notes: A high-current, high-energy, and long-pulse positive ion source for the KSTAR neutral beam system is being developed on the basis of proven technology. The original prototype ion source was the TFTR developed by LBNL, but the accelerator slit grid brazed with shaped molybdenum tubes was a barrier for success of the copied work. In order to cover the technical and economical problems caused by the molybdenum tubes, a new OFH copper grid with circular apertures has been designed and manufactured. Cooling circuits aligned along every line of the aperture arrays are made with the help of gun drills. The test and the first experimental results of the upgraded ion source, such as high-voltage characteristics, cooling characteristics, discharge characteristics, and first beam extraction characteristics are described. © 2002 American Institute of Physics.

Notes: For the construction of an electron cyclotron resonance (ECR) charge breeder at the KEK-JAERI radioactive nuclear beam facility, we have made and tested a pilot charge breeding system consisting of two compact-sized ECR ion sources. Using a simulation code, we have investigated the geometrical beam acceptance of the present system for the external injection of ions of interest into ECR plasma. Following discussions on the ECR plasma influenced by a deceleration potential for the external injection, the charge breeding efficiency for Ar ions is presented and discussed. © 2002 American Institute of Physics.

Notes: The ability to generate various ion species makes the multicusp plasma ion source an excellent candidate for maskless resistless lithography application. In this article, the mass spectra of both positive and negative ions for phosphorus, BF3, and oxygen multicusp plasmas are presented. It is shown that over 90% P+ ions are produced. The production of BF2+ and O2+ increases with increasing gas pressure, and decreases with increasing source power. With optimization of source operating parameters, approximately 85% BF2+ and over 90% O2+ have been achieved. © 2002 American Institute of Physics.

Notes: Many applications of ion sources (e.g., ion implantation in the semiconductor industry) are very sensitive to particles and have tight specifications on allowable particle number and size. Among the sources of particles are the ion source itself (due to either nucleation in the plasma, or ion bombardment of the surfaces), and the extraction electrodes (due to ion bombardment). This article investigates the processes to which such particles are subjected during their flight through the extraction electrodes. They travel at much lower velocity than the accelerated ions due to their much larger mass, and so are bombarded by these increasingly energetic ions. The processes considered during the trajectory of the particle are: charging, acceleration in the electrode fields, entrapment within the suppression gap, heating from ion bombardment, radiation cooling, melting, vaporization, and Coulomb explosion. These processes are all modeled simultaneously as the trajectory of the particle is followed. A general condition for particle trapping is developed, and it is found that in the case of silicon particles, these particles can be annihilated by a combination of Coulomb disintegration and vaporization. © 2002 American Institute of Physics.

Notes: A test facility has been constructed to evaluate negative ion beams from small gaseous samples for accelerator mass spectrometry applications. The positive ion beams from the microwave ion source are passed into a charge-exchange canal (CXC) where the ions exchange electrons with magnesium vapor and become negatively charged. Positive molecular ions were either neutralized or broken up into atomic ions and neutral atoms and molecules by collision processes. Most of the resulting particles were suspected to be neutrals. In studies with injections of CO2 pulses, the resulting positive and negative 12C current peaks gave a 0.09% yield of C− ions from CO2 molecules, which includes a charge-exchange efficiency of 10%. Since nitrogen does not form a stable negative ion, 14N background is virtually eliminated after the beam goes through the CXC, which is necessary for radiocarbon measurements. © 2002 American Institute of Physics.

Notes: We describe the design, construction, and implementation of a simple and inexpensive, yet versatile surface magneto-optic Kerr effect (SMOKE) setup designed to operate in conjunction with the electrodeposition of magnetic layers both in situ and ex situ. The system is based on a homemade electromagnet and commercially available components. The sensitivity of the system is demonstrated by measuring ex situ SMOKE hysteresis loops of Co thin films (down to three monolayers thick) electrodeposited onto a Au(111) electrode substrate. © 2002 American Institute of Physics.

Notes: A miniature torquemeter for use in a pulsed magnetic field is developed by utilizing a commercially available piezoresistive microcantilever. The high sensitivity of ∼5×10−13 Am2 at 38 T is achieved. The response to faster signals were considerably improved due to high eigenfrequency of the cantilever (f∼250–300 kHz). In this article, we successfully demonstrate the magnetic torque data of samples of sub-μg order in pulsed magnetic fields up to 38 T with pulse duration of less than 60 ms. We also found that the de Haas–van Alphen data are in good agreement with the previous reports obtained in steady magnetic fields. © 2002 American Institute of Physics.

Notes: We have developed a method for determining the magnetic easy direction (crystalline direction of maximum magnetic susceptibility) in powdered samples of paramagnetic crystals using nuclear magnetic resonance (NMR) spectroscopy. Single-crystal powder grains are aligned using a magnetic field both with and without rotation of the sample about an axis perpendicular to the alignment field. Depending on the magnetic easy direction of the material, only one method produces a good crystalline alignment. By qualitatively comparing the direction-dependent powder-pattern NMR spectra of samples aligned using the two alignment methods, we have successfully determined the magnetic easy directions in CePtSi and Y0.85U0.15Pd2Al3 compounds. © 2002 American Institute of Physics.

Notes: The radio frequency (rf) magnetic field in a microwave cavity ought to be uniform along a line sample in electron paramagnetic resonance (EPR) spectroscopy so that all portions respond uniformly. Mett, Froncisz, and Hyde discovered a way to achieve this objective [Rev. Sci. Instrum. 72, 4188 (2001)]. Their resonators consisted of three regions, a central section for the sample with dimensions at the cutoff condition, and two end sections that had the same cross section as the central section but were made electrically larger by filling them with a low-loss dielectric. The end sections were each one-quarter wavelength long. We have found that the dielectric in the end sections can be omitted and the dimensions made correspondingly larger. Effects of the resulting discontinuities in cavity cross sections perpendicular to the cavity axis have been analyzed using finite element high frequency structure simulator calculations. Closed form expressions for Q values and relative rf field values have been obtained. The length of the uniform field region is decreased somewhat by the discontinuities (∼1 cm at X band). This disadvantage is outweighed by the benefits of higher Q values and elimination of impurity EPR signals from the dielectric materials. End sections may be cylindrical or hemispherical for cylindrical modes and rectangular or hemicircular for rectangular modes. © 2002 American Institute of Physics.

Notes: A deconvolution technique to eliminate the azimuthal contribution from two-dimensional (2D) images of three-dimensional momentum trajectories is presented. The technique, which in some respects is superior to Abel and similar numerical inversion methods, exploits numerical simulation to generate a 2D polar representation of the dynamics where the radius from the center of the image is proportional to the magnitude of the momentum and the angle is the ejection angle relative to the polarization axis of the laser. A sample deconvolution for the three-body Coulomb explosion of NO2 is shown. © 2002 American Institute of Physics.

Notes: A novel design for an airborne NOy converter was implemented, characterized in the laboratory, and used extensively for in situ tropospheric and stratospheric measurements of total reactive nitrogen (NOy). During field deployments, the converter is mounted outside the aircraft fuselage, avoiding the need for an inlet line. In flight, the converter can be calibrated by the addition of standard gases close to the sample inlet, compensating for any changes in the instrument sensitivity caused by changing operating conditions. The system has been used successfully during several Stratosphere Troposphere Experiments by Aircraft Measurements campaigns in the lowermost stratosphere and upper troposphere for the measurement of total reactive nitrogen. The detection limit of the system is approximately 100 pptv for 10 s integrated data (2σ). The precision, deduced from the reproducibility of the in-flight calibrations, is 7% and the accuracy is about 30%. Laboratory studies demonstrate that interference from HCN, NH3, and CH3CN is negligible for background conditions. © 2002 American Institute of Physics.

Notes: We present a setup for stimulated desorption experiments of negative ions using low energy incident electrons and time-of-flight identification of the desorbed ions. It consists of a pulsed electron gun, an electrostatic focusing system, and a channel plate detector setup. Electron beams down to sub-eV energies can be used due to electrostatic shielding and the compensation of the earth's magnetic field by a set of Helmholtz coils. The main advantage is the large acceptance for ions of all masses, energies, and desorption angles at the same time, which keeps measuring time reasonably short and allows us to gain information before degeneration of the irradiated sample occurs, even if weak desorption channels are investigated. We demonstrate the power of our setup with first results from a boron doped, (100)-oriented diamond sample, which is partly oxidized and partly hydrogenated with some water contaminations on it. Different binding states of oxygen are disclosed clearly by different desorption thresholds. The C–O binding on oxidized diamond forms a carbonyl group. The 1b2 orbital of water can be seen in a O desorption threshold. The yield of negative hydrogen desorption shows a linear increase for incident electron energies higher than 13 eV. It results from a dipolar dissociation as has been published previously. © 2002 American Institute of Physics.

Notes: This article focuses on optimizing the signal to noise ratio (SNR) of a three-wavelength light-emitting diode (LED) near-infrared continuous-wave (cw) imager and its application to in vivo muscle metabolism measurement. The shot-noise limited SNR is derived and calculated to be 2×104 for the physiological blood concentrations of muscle. Aiming at shot-noise limited SNR performance and fast imaging, we utilize sample and hold circuits to reduce high-frequency noise. These circuits have also been designed to be parallel integrating, through which SNR of 2×103 and 2 Hz imaging acquisition rate have been achieved when the probe is placed on a muscle model. The noise corresponds to 2×10−4 optical density error, which suggests an in vitro resolution of 15. 4 nM blood volume and 46.8 nM deoxygenation changes. A 48 dB digital gain control circuit with 256 steps is employed to enlarge the dynamic range of the imager. We utilize cuff ischemia as a living model demonstration and its results are reported. The instrument is applied during exercise to measure the changes of blood volume and deoxygenation, which provides important information about muscle metabolism. We find that the primary source of noise encountered during exercise experiment is from the random motion of muscle. The results demonstrate that the LED cw imager is ideal for the noninvasive study of muscle metabolism. © 2002 American Institute of Physics.

Notes: The hardware necessary for the electro-optic study of conducting polyelectrolyte solutions is frequently not commercially available or financially practical. The designs of an electrical rectangular pulse switch and polarity-reversing relay switch capable of producing 3 kV 5 A direct current pulses lasting longer than 100 μs are presented. As an example of the operation of this equipment, the electric birefringence of an aqueous solution of the Pseudomonas bacteriophage Pf1 in tris/EDTA buffer is presented. © 2002 American Institute of Physics.

Notes: This article presents and compares two differential methods for measuring the complex permittivity of dielectric materials: In the first method, two measuring cells built as coaxial transmission lines of identical cross section and terminations but different lengths are filled with a sample of the dielectric material. The complex dielectric permittivity is determined from the scattering parameter measurements and the length difference between the two cells, neglecting the resistive losses due to the cells. The second method is a double-differential one: Repeating measurements on the same cells empty, no other knowledge or limiting assumption is required. © 2002 American Institute of Physics.

Notes: The chromium doped spinel crystals, MgAl2O4:Cr3+, have been grown using floating zone technique and its application for the fiber-optic thermometer is discussed on the basis of the temperature dependence of the fluorescence lifetime. Lifetimes of the spinel crystals (τ=10 ms), which decrease with temperature, were about 3 times larger than that of the ruby crystals (τ=4 ms) at room temperature. Temperature coefficients of the photoluminescence (PL) lifetimes for spinel crystals (37 μs/K) are also 3 times longer than that for the ruby crystals (10 μs/K). The spinel crystals are potentially useful sensor probes for the fiber-optic thermometer, which have an advantage of high sensitivity due to long PL lifetime and large temperature coefficient. © 2002 American Institute of Physics.

Notes: This article presents design equations for calculating the compliance or spring rate of rectangular single-axis hinges and right circular hinges. The design equations are the result of an exact deduction and are concise in their expressions, so it is more convenient to use them in calculating and analyzing flexure hinges and flexure hinge mechanisms. Comparing these with the exact design equations of Paros and Weisboro [Mach. Des. 37, 151 (1965)], it is suggested that the equations of this article are effective. Limitations of the simplified equations of Paros and Weisboro and the approximate equation of Smith et al. [J. Phys E 20, 977 (1987)] are discussed. While calculating the compliance of flexure hinges, several important points are mentioned. © 2002 American Institute of Physics.

Notes: A prototype of the electrical impedance spectroscopy (EIS) device for the measurement of internal moisture gradients in wood was developed. The EIS device consists of a hand-held probe connected to a control unit interfaced with a portable personal computer and a power unit. In the measurement, parallel flat electrodes of the measuring probe are laid against the wood specimen and the sine wave excitation is applied in the frequency range 1–100 kHz. The measured amplitude and phase spectral data were analyzed using the model based on constant phase elements. A spectral analysis software package was designed for measurement of subsurface transverse moisture gradients. The EIS device was tested with many types of uniform, desorption, and absorption gradients in lumber, pulpwood, and log specimens from spruce, pine, and birch. The EIS device can be easily transferred in a small case allowing field measurements. © 2002 American Institute of Physics.

Notes: A standard system for low magnetic fields has been developed at the Korea Research Institute of Standards and Science. The system consists of a precision solenoid, He–Cs atomic magnetic resonance magnetometer, and apparatus for three-axis compensation of the Earth's magnetic field. The variations of the Earth's magnetic field are automatically compensated within 0.1 nT/h by a Cs atomic magnetic resonance field controller. The solenoid reproduces a dc field that is uniform at better than 3×10−7 within ±2 cm around the center. The experimentally measured coil constant and temperature coefficient of the solenoid are 1.231 0596×10−3 T/A (25 °C) and 3.8×10−7/°C, respectively. The standard serves for the calibration of magnetometers and uniform field coils, and also supports experiments related to research in magnetic fields in the range of (0.02–1.2) mT with (2–10)×10−6 uncertainty. © 2002 American Institute of Physics.

Notes: Remodeling components from two commercially available spark plugs and adding a tungsten wire as the central electrode construct a cylindrical-shaped magnetized plasma torch module. A ring-shaped permanent magnet is used to provide an axial magnetic field, which rotates the discharge to prevent the formation of hot spots. The electric properties of this magnetized torch module are studied and compared with those of the unmagnetized one. © 2002 American Institute of Physics.

Notes: The Nuclear Regulatory Commission (NRC) in 1998 completed a study of emerging technologies that could be applicable to measurement systems in nuclear power plants [H. M. Hashemian et al., "Advanced Instrumentation and Maintenance Technologies for Nuclear Power Plants," NUREG/CR-5501 (1998)]. This study concluded that advanced fiber optic sensing technology is an emerging technology that should be investigated. It also indicated that there had been very little research related to performance evaluation of fiber optic sensors in nuclear plant harsh environments, although substantial research has been performed on nuclear radiation effects on optical fibers in the last two decades. A type of Fabry–Perot fiber optic temperature sensor, which is manufactured by Fiso Technologies in Canada, is qualified to be a candidate for potential applications in nuclear radiation environment due to its unique signal processing technique and its resistance to power loss. The gamma irradiation effects on this type of sensors are investigated in this article. Two sensors were irradiated in a gamma irradiation field and one of them was irradiated up to a total gamma dose of 133 Mrad. The sensor on-line performance was monitored during each gamma irradiation test. Furthermore, the sensor static and dynamic performance before and after each irradiation test were evaluated according to the Standard ISA-dS67.06.01 ("Performance Monitoring for Nuclear Safety-Related Instrument Channels in Nuclear Power Plants", Standard ISA-dS67.06.01, Draft 7, Instrument Society of America, 1999). Although several abnormal phenomena were observed, analysis shows that gamma irradiation is not accredited to the abnormal behavior, which implies that this type of sensor is suitable to a gamma irradiation environment with a high gamma dose. © 2002 American Institute of Physics.

Notes: We report on the continuous measurement of fluorescence lifetimes at low light levels. Fluorescence photons following pulsed excitation generate a pulse sequence with exponentially distributed amplitudes and interphoton times at the output of a time-to-amplitude converter. This sequence is turned into a continuous step function and is time averaged with an adjustable bandwidth. For a single-exponential decay, our approach yields identical results as would be obtained from fitting fluorescence decays, while being a real-time technique. The proposed technique performs especially well at low count rates. We demonstrate the applicability of the method at the example of confocal fluorescence lifetime imaging of single molecules. © 2002 American Institute of Physics.

Notes: I describe an inexpensive and portable method used to conduct bit error rate test measurements in an aircraft at altitude to measure susceptibility of gigabit fiber optic transceivers to ionizing radiation. This method uses a built-in test feature of Texas Instruments GigaBit Ethernet transceiver chips. During a 20 min flight at 39 000 ft altitude, none of the eight test channels using Finisar FTRJ-8519-1 fiber optic transceivers indicated any bit errors. © 2002 American Institute of Physics.

Notes: A simple, compact source of low-temperature, spatially and temporally uniform air plasma using a Telsa induction coil driver is described. The low-power ionization discharge plasma is localized (2 cm×0.5 cm×0.1 cm) and essentially free of arc channels. A Teflon coated rolling cylindrical electrode and dielectric coated ground plate are essential to the source's operation and allow flat test samples to be readily exposed to the plasma. The plasma is a copious source of ozone and nitrogen oxides. Its effects on various microbes are discussed. © 2002 American Institute of Physics.

Notes: An experimental investigation of the characteristics of soft x-ray output emitted from a pinch plasma using a laser-induced Au plasma has been performed. The Au plasma is produced by focusing a laser pulse with a focal spot diameter of 100 μm on the tip of an Au pin anode electrode. A pulsed pinch discharge driven by a Marx generator utilizes the plasma as a discharge medium. Soft x-ray output with a pulse duration of ∼120 ns, an energy of ∼1 μJ mm−2, and an effective photon energy of ∼1 keV, has been obtained with the discharge. It is shown that the output characteristics depend strongly on the Marx charging voltage, laser pulse energy, and delay time of the discharge from the laser irradiation. © 2002 American Institute of Physics.

Notes: We have developed a simple, compact, high power, diode-pumped, intracavity frequency-doubled, Nd:Y3Al5O12 laser capable of generating output powers of up to 70 W at 10 kHz, and 16.5 W at 1 kHz. The output beam quality is highly multimode, with an M2∼30. This, combined with the short output pulse duration of 36–60 ns, and the high average power, makes this laser ideal for pumping ultrafast Ti:sapphire laser amplifier systems. © 2002 American Institute of Physics.

Notes: The knowledge of the detection efficiency of the microchannel plate is of upmost importance in many applications using this type of particle detector. However, few attempts have been made to measure the absolute value of the detection efficiency of microchannel plates. In this article, a new way of accurately measuring the absolute value of the detection efficiency is described. When particles hit the detector in the interchannel web of the microchannel plate, secondary electrons are generated. These secondary electrons can be returned to neighboring channels by means of an electric field applied at the front face of the detector. The resulting increase in the detection efficiency has been quantified using the absolute measurement of the detection efficiency. It is found that the value of the returning field has to be carefully set in order to prevent detection artifacts that may lead to a wrong estimation of the detection efficiency. In the best conditions, the detection efficiency increase reaches 40%. © 2002 American Institute of Physics.

Notes: A new steady-state, low-energy, and high-flux ion beam test device has been developed to study erosion, re-deposition, and hydrogen retention mechanisms of plasma facing materials under high flux conditions. Source plasma was produced by electron cyclotron resonance discharge with 2.45 GHz microwave. Ion extraction was made by spherical multiaperture triode electrodes to obtain high ion flux at the focal point. Ion extraction aperture geometry was designed so that high current density can be obtained in the case of low energy (〈500 eV) by applying high deceleration voltage. It was demonstrated that low-energy and high-flux ion beam can be produced by increasing deceleration voltage with the fixed acceleration voltage (beam energy). In the case of hydrogen beam energy of 300 eV, beam power density has rapidly increased with a deceleration voltage over accel–decel ratio 4, and maximum beam flux is 4.1×1020 H/m2 s. On the other hand, maximum beam flux of 3.6×1021 H/m2 s was obtained for 3 keV hydrogen beam. These fluxes are much higher than that of conventional mass analyzed ion beam (〈1.0×1020 H/m2 s). © 2002 American Institute of Physics.

Notes: The study of negative ion production in the multicusp negative ion sources (MS) was done by the directed deposition of well-defined amount of cesium into MS, by the cesium recovery from the polluted layers in the MS and by the plasma grid masking. The data obtained evidences the surface-plasma mechanism of negative ion production in the MS. It is shown that a dynamic cesium-tungsten coverage on a plasma grid surface provides the enhanced H− production in the MS. The Cs+W coverage is produced on the hot plasma grid surface due to coadsorption of cesium and of tungsten, evaporated from filaments. The permanent flux of cesium to plasma grid coverage is produced by the thick Cs+W reservoir with a high (75%) percentage of cesium on the cold anode surface. A relatively high cesium seed with a rate of about 20 mg/1 h/30 shots operation is necessary to support the increased H− production in the regular MS. Electrode processing by an additional discharge recovers the cesium from the aged coverage and enhances the H− production without an additional cesium seed. Recovery processing permits the use of deposited cesium more efficiently and to minimize cesium addition during the MS long-term operation. An essential decrease of cesium escape to accelerator and an improvement of injector high voltage operation is produced by introducing the shutter mask at plasma grid surface. The shutter mask experiment displayed, that 〉60% of H− beam current was born on the hot shutter mask surface. The source operation with a high negative shutter mask biasing and an increased hydrogen pressure resulted in a 35% higher H− yield, than of regular MS. © 2002 American Institute of Physics.

Notes: Typical magnetic materials are experimentally characterized. Particularly our efforts are concentrated on deriving a core-loss scaling in operation region with minor B–H loops for highly repetitive voltage modulators. The core losses are evaluated as functions of magnetization rate and flux swing using semiempirical equations based on magnetization models. A prototype induction module has been successfully operated up to 1 MHz and the loss values are adapted well to the core-loss criterion. © 2002 American Institute of Physics.

Notes: A technique of spatial and temporal diagnostics of an electron beam was investigated experimentally by Thomson scattering of the electron beam with a femtosecond laser beam at a 90° configuration. The spatial structure of the electron beam was measured by scanning the laser across the electron beam in the Thomson scattering, and compared with imaging of the beam profile on a phosphor screen using a charge coupled device. By scanning the femtosecond laser beam in time along the electron beam, we measured the temporal density distributions of short and long electron bunches which were produced in a photocathode rf gun with laser injection phases of 30° and 55°. A subpicosecond time slice of the actual electron beam was achieved in the measurement. © 2002 American Institute of Physics.

Notes: In order to measure fine scale fluctuations of visible emission in plasmas, the four-beam correlation method is proposed and its feasibility is studied. This is an extension of the conventional cross beam techniques and uses four beams (i.e., four lines of sight), which lie in two parallel planes. While two beams in the same plane provide the fluctuation levels at the intersection, two beams in different planes provide correlation as a function of the distance between the planes. Various cases are considered, and the method feasibility is shown. This method is useful for reconstructing a two- or three-dimensional wave-number spectrum. In addition, it can be used to measure the magnetic field direction assuming that the parallel correlation length is longer than the perpendicular one. © 2002 American Institute of Physics.

Notes: A matched filter analysis has been developed to identify the amplitude and phase of magnetohydrodynamic modes in DIII-D tokamak plasmas using magnetic probe signals (δBp). As opposed to conventional Fourier spatial analysis of toroidally spaced probes, this analysis includes data from both toroidally and poloidally spaced magnetic probe arrays. Using additional probes both improves the statistics of the analysis and more importantly incorporates poloidal information into the mode analysis. The matched filter is a numeric filter that matches signals from the magnetic probes with numerically predicted signals for the mode. The numerical predictions are developed using EFIT equilibrium reconstruction data as input to the stability code GATO and the vacuum field code VACUUM. Changes is the plasma equilibrium that occur on the same time scale as the mode are taken into account by modeling simple matched filter vectors corresponding to changes in total plasma current, plus vertical and horizontal plasma shifts. The matched filter method works well when there is good understanding of a mode and good modeling of its structure. Matched filter analysis results for a fast growing ideal kink mode, where equilibrium change effects are minimal, show the effectiveness of this method. A slow growing resistive-wall mode (RWM) is also analyzed using the matched filter method. The method gives good results for identifying the amplitude and phase of the RWM but the simple equilibrium vectors are insufficient for complete elimination of equilibrium changes on this time scale. An analysis of the computational requirements of the scheme indicates that real-time application of the matched filter for RWM identification will be possible. © 2002 American Institute of Physics.

Notes: A simple interference filter spectrometer, together with a modulated neutral diagnostic beam is used on the Tore Supra tokamak for the measurement of carbon impurity profiles by charge exchange spectroscopy. A temporal resolution of 8 ms with a good signal to noise ratio is obtained with a neutral hydrogen beam of about 1 A equivalent neutral current at the plasma edge at 45 kV. Experimental results with ion cyclotron heating show that fast changes of the heating power are followed by transient modifications of the carbon impurity profile. The evolution of the C6+ profile from peaked to hollow and back to normal can be followed step by step and a typical diffusion time of about 30 ms is measured. © 2002 American Institute of Physics.

Notes: This article describes hardware and software solutions to a need which is comprised of (i) acquisition of a large volume of high speed data with multiple time scales, (ii) control of various operational parameters of device and diagnostics, and (iii) processing and management of the acquired data for a large volume plasma device. The solution relies on the base of a VXI bus and uses a standard PC with a Windows 98/NT operating system and C as the programming language. The system is networked with the existing network with the result of allowing a large data storage space of processing facilities from any terminal in the laboratory.© 2002 American Institute of Physics.

Notes: Detection of systematic errors is an important issue in the treatment of measurement data. Existing methods such as the t-detection method and the residual error method are based on the statistics theory that requires large sample sizes and known distributions. For small sample sizes and unknown distributions, these methods could become ineffective. To solve this problem, a new method is proposed to detect the systematic errors in a measurement process, based on fuzzy set theory. In the proposed method, the distribution of measured data may be unknown and the sampling size small. Mathematical models for systematic error detection are presented together with criteria for the detection. Results of the case studies show that the proposed method is effective and the proposed criteria are consistent in identifying monotonic and periodic systematic errors. © 2002 American Institute of Physics.

Notes: We have developed a surface-contact sensor on the basis of a tuning fork which differs from the previously described ones in that it has a high operating speed (up to 100 times as fast as the so-called Q limit), requires no external piezoelectric drive, has a sufficiently high sensitivity, and features a "soft" probe attachment which makes the lifetime of the probe equal to that of the standard atomic force microscopy. When using a "soft" probe with a rigidity of 0.5 N/m, one can reliably detect probe tip-to-sample distance variations as small as 0.1 nm. The resonance frequency resolution attained amounted to 2×10−3 Hz. The rate of transient rise is τ=1.5 ms (this refers to the response time of the sensor proper with the Z-coordinate feedback loop open and not to the response time of the microscope as a whole). We have theoretically substantiated the fact that the Q limit, where Q∼10 000 is the Q factor of the tuning fork proper, is not a fundamental restriction on the operating speed of the sensor. This sensor characteristic is governed by another independent quantity, namely, Q1∼100: the quality factor of the tuning fork preamplifier system that can be varied to suit the experimenter. In that case, the fundamental force limitation on the sensitivity of the sensor, associated with its operating speed and the Q factor of the tuning fork, is Fnoise(approximate)10.4 nN/((square root of)Q(square root of)Q1). © 2002 American Institute of Physics.

Notes: An experimental setup for the deposition of mass-selected clusters using a laser vaporization source and a magnetic field mass selector is presented. Nondestructive deposition and a coverage of 1% of a monolayer within 5 h are achieved for mass-selected metallofullerene clusters as demonstrated for deposited Ce@C60 on highly oriented pyrolytic graphite. © 2002 American Institute of Physics.

Notes: An x-ray diffraction apparatus, consisting of a load cell, a stretching device, and a cryogenic cell, has been constructed to observe the mechanical deformation of the crystal lattice of polymers at cryogenic temperature. The polymer specimen could be cooled down to 18 K using this apparatus. The equatorial diffraction profiles of polymer specimens were observed under various temperatures and loads with 18 K minimum temperature. The equatorial lattice spacings of polyethylene (PE) decreased at 18 K compared with those at 300 K; however, they were elongated by a constant applied tensile stress. The elastic modulus Et of the crystalline regions of PE in the direction perpendicular to the chain axis was evaluated. The Et value for the (200) plane of PE increased to 11 GPa at 18 K from 3.2 GPa at 300 K. This is considered to be due to the increase of the van der Waals interactions between the chains in the crystal lattice at very low temperature, where the incoherent thermal vibrations of the atoms can be ignored. © 2002 American Institute of Physics.

Notes: A sensitive technique for measurement of lateral dimension of the ultrathin polymeric films is developed. By comparing width profiles at various loads, the lateral and longitudinal strains were obtained, and were used to get the Poisson's ratio. Lateral dimensional changes at a very light load and a range of temperatures and relative humidities were used to measure coefficients of thermal and hygroscopic expansion. The Poisson's ratio of standard polyethelene terephthalate (PET), tensilized PET, standard polyethelene terephthalate (PEN), tensilized PEN and supertensilized PEN were measured at 25 °C/15%RH, 25 °C/50%RH, 25 °C/80%RH, and 40 °C/50%RH. The data range from 0.29 to 0.47. It is found that tensilized films have a higher Poisson's ratio than balanced films. The effects of temperature and humidity on the Poisson's ratio are related to the materials' molecular structure. An increase in temperature generally increases the Poisson's ratio for the polymeric films. When relative humidity increases, the Poisson's ratio of balanced films increases, while those of tensilized films remains constant or decreases slightly. The Poisson's ratio is also affected by the stress magnitude that is used in the measurement; high stress usually results in a high Poisson's ratio. By simultaneous loading and calibration, long term lateral dimensional deformation behavior of these films was studied. The results are consistent with the reported data measured by standard techniques. © 2002 American Institute of Physics.

Notes: A blue light emitting diode (LED) has been used as the excitation source in a series of sensor-related characterization studies carried out on thermographic phosphors. The motivation for the described effort is the potential utility of LEDs for fluorescence based thermometry applications. The phosphors that were evaluated included La2O2S:Tb, Gd2O2S:Tb, Y2O2S:Pr, and various other rare-earth activated ceramics. Periodic and pulsed excitation of the phosphors was demonstrated, with LED gate-on times of 10–12 μs at operating levels of (approximate)25 V. The spectral response of the phosphors under these conditions is described, and the implications of such devices for the design of electro-optic instrumentation systems (including remote thermometry applications) are discussed. A beneficial finding of this work is that a good match between the LED emission spectrum and the phosphor excitation spectrum is not required in order to produce useful, detectable fluorescence. © 2002 American Institute of Physics.

Notes: Si–N based membrane calorimeters are a promising technology for the study of thermal properties of small quantities of materials in both pulsed and steady-state magnetic fields to 60 T and beyond. We present results that demonstrate our ability to measure the heat capacity of thin film samples from 2–300 K in steady-state fields up to 8 T. These measurements include the magnetoresistance of the Pt and Nb–Si thermometers and focus on confirming that the thermal conductance of the Si–N membrane does not change significantly in magnetic fields. This means the thermal conductance needs to be measured only in zero field, reducing the measurement time in high field. This is particularly important for future measurements in fields up to 60 T. © 2002 American Institute of Physics.

Notes: An air-gap capacitance cell is presented, designed for temperature dependent dielectric spectroscopy on materials that cannot be contacted with surface electrodes: materials such as porous foams and membranes or solvent containing polymer resins. The capability of the system is demonstrated with measurements up to 300 °C, performed on a 60 μm porous poly(tetrafluoroethylene) (PTFE) and on a precured hybrid system of a porous PTFE, soaked with the low-k aromatic ether polymer: poly(1,1,1-triphenyl ethane perfluorocyclobutylether). The measurement system allows recording of the dielectric loss spectra with high resolution, barely influenced by thermal expansion or ionic conductivity. © 2002 American Institute of Physics.

Notes: A procedure for choosing the appropriate chopping frequency (f) for the surface photovoltage spectroscopy (SPS) measurements in order to obtain the absorption related features is presented. We could obtain the absorption edge of thick n+ GaAs wafer (thickness (approximate)700 μm) by performing SPS measurements at f≥1 kHz at room temperature (300 K). The similar information for semi-insulating (SI) GaAs could not be obtained due to the carrier trapping at deep levels or surface states at 300 K. However, we could obtain the absorption edge of SI-GaAs by performing SPS measurements at 395 K at f=3 kHz. Here, we demonstrate the capability of the SPS technique to measure large absorption coefficient (α) values for thick wafers by performing SPS measurements and normalizing this with the reported α value at one wavelength in the above band gap region. For comparison, we also perform quasisimultaneous SPS and transmission spectroscopy (TS) measurements. The SPS technique could provide α values up to 104 cm−1 for 700-μm-thick GaAs wafers, whereas TS could only measure α values up to about 15 cm−1. An improved design of the sample holder for measuring the surface photovoltage in the chopped light geometry, which increases the signal strength by reducing the gap between the top electrode and the wafer in a controlled manner, is presented. This ensures that there is no sample damage or contamination. © 2002 American Institute of Physics.

Notes: We report a novel sensor-based high throughput screening (HTS) system for identification and quantitation of volatile substances in combinatorial chemical libraries. The measurement method employs a combination of a periodic introduction of a minute amount of a liquid sample into the HTS system, rapid evaporation of volatile components in the sample at room temperature, and dynamic measurement of a generated vapor pulse. These measurements are performed using an array of four 10 MHz acoustic-wave thickness-shear mode sensors coated with different chemically sensitive films. Developed HTS system is applied for screening of multiple samples such as those created in combinatorial chemical libraries of catalyst candidates in an industrially important arene oxidation process. The temporal modulation of the concentration of analyte vapors and measurement of both the temporal profile and the magnitude of the response improves sensor selectivity and makes possible robust identification and quantitation of arene oxidation components such as cresol and benzoquinone in multicomponent combinatorial mixtures with reduced number of sensors in the array. Different solvents such as water, acetonitrile, benzene, and toluene do not alter the response of sensors to analytes. Depending on the gas flow rate, quantitative measurements are performed 10–150 s after the sample introduction and provide significant throughput advantage over gas-chromatographic instruments. Determinations of mixtures of analytes in a variety of solvents are performed using multivariate locally weighted regression. This data analysis method provides the root mean squared error of prediction of less than 2 μg when measurements of cresol and benzoquinone amounts ranging from 0 to 50 μg are performed in 2 μL samples. This method of dynamic sensor-based measurements allows for instrument miniaturization and increases the usefulness of the instrument in space-limited applications. Upon operation of multiple sensors in parallel, effective analysis of dense combinatorial libraries of materials is possible. © 2002 American Institute of Physics.

Notes: An automated procedure has been developed for a constant voltage anemometer to obtain in situ heated and cold resistances of a hot wire in each measurement cycle. From these parameters mean velocity can be deduced in the presence of ambient flow temperature variations, using a calibration curve based on, e.g., King's law with the assumption of constant coefficients over a given temperature range. The method requires only one hot wire. This is a definite advantage over previous methods established for constant current or constant temperature anemometers where an additional temperature sensor is needed, with a separate temperature calibration of the hot wire. Results from a typical test are presented to demonstrate the procedure. The prototype tested was a 400 kHz bandwidth unit and the measurement cycle can be changed through software commands to suit each test requirements. © 2002 American Institute of Physics.

Notes: A linear motion device was designed and built to move small sample cells within the confined space of a liquid nitrogen Dewar cryostat. Instead of the often-used methods of flowing or rotating samples to generate motion, this cryostat insert simply translates the sample cell while maintaining atmospheric isolation. Accurate, repeatable and rapid translation over a 5 cm range with peak linear velocities of 1 m/s is attainable. The insert is constructed mainly from commercially available components and can be built with minimal effort. Another benefit is that the cryostat insert uses commercially available sample cells, allowing for maximal flexibility in satisfying pathlength and volume requirements and the cells can be easily replaced during the duration of the experiment. The motion device system can be easily installed into existing experimental apparatuses with confined volumes with minor modifications and can be used with liquid helium cryostats or for use in high vacuum applications. This motion is demonstrated by collecting temperature dependent ultrafast signals from the laser dye Rhodamine 640 in viscous glycerol at 170 and 293 K. © 2002 American Institute of Physics.

Notes: © 2002 American Institute of Physics.

Notes: This talk will describe proposed studies of atomic- and nanoscale dynamics in condensed matter which take advantage of the high coherent x-ray flux to be produced by future x-ray free-electron laser (FEL) sources, such as the Linac Coherent Light Source at Stanford. In particular, I will focus on the current status and future prospects for photon correlation spectroscopy using coherent x-rays (XPCS), and the use of the ultrashort pulse structure of the x-ray FEL to observe dynamics into the femtosecond range. © 2002 American Institute of Physics.

Notes: A three-dimensional (3D) microstructure fabrication technique utilizing hard x-ray lithography has been developed. In this technique, as the intensity distribution of the x rays is controlled by a newly developed bending mirror, the exposure residual depth of polymethylmethacrylate (PMMA) resist is controlled over the exposed area. The maximum difference of depths was approximately 50 μm over the large area more than 60 mm (horizontal)×5 mm (vertical). We also investigated the effects of controlling the beam intensity distribution on the obtained 3D resist pattern shapes by changing x-ray mask absorber shapes and angle. 3D PMMA patterns with inclined shape sidewall and graded depths were successfully fabricated. We believe this technique greatly expands applications of the LIGA process. © 2002 American Institute of Physics.

Notes: Using unmonochromotized synchrotron radiation and a simple image detecting system at the 5C1 beam line of PLS in Korea, human cadaverous finger bones of various conditions were visualized with extremely high resolution. Bone images of synchrotron radiation were verified by figures and their characteristics qualified with respect to the calcium content. They were also compared with images and information from other radiological instruments including conventional x-ray, dual energy densitometry and micro-computed tomography. Synchrotron images of older human cadaverous bones in poorer condition showed flat and narrow traveculae with fragmentation, and shift were noted to the right by brightness. These findings seem to be considered as valuable information for the diagnosis of bone related diseases in the clinic. © 2002 American Institute of Physics.

Notes: Several compound materials were synthesized from N2,H2O vapor, and CO2 gas mixtures using synchrotron radiation induced photochemical reactions at atmospheric pressure and at room temperature. Ammonium and nitrogen oxides were successfully synthesized from N2,H2O vapor, and O2 gas mixtures. It was also found that organic compounds such as carboxyl acids and amino acids were formed from a N2,H2O vapor, and CO2 gas mixture. © 2002 American Institute of Physics.

Notes: We are planning to construct a 3 GeV synchrotron light source in the Republic of Armenia called Center for the Advancement of Natural Discoveries using light emission—CANDLE. The purpose of the machine is to produce high flux and high brightness photon beams from bends and insertion devices in the soft and hard x-ray spectrum range from 1 to 50 keV. The main elements of the light source are an S-band linac, a full energy booster, and a 16-cell double bend achromatic storage ring. We will discuss the main parameters of the machine, the insertion devices, and the preliminary beamlines instrumentation. © 2002 American Institute of Physics.

Notes: The free electron laser at Jefferson Laboratory is the first of a new generation of light sources based on a photoinjected energy recovered linac. The present machine has a 40 MeV electron beam and an average current of 5 mA. The electron bunches are extremely short with full width at half maximum values that are in the few hundred femtosecond regime. These electron bunches pass a chicane around the optical cavity, and therefore, emit synchrotron radiation. In the far-IR region, the wavelength of the light being emitted approaches that of the electron bunch length, giving rise to multiparticle coherent enhancement. The result is a broadband spectrum whose average brightness is more than five orders of magnitude higher than can be obtained from conventional incoherent synchrotron IR sources. We will discuss preliminary measurements of this radiation, and applications to spectroscopy and imaging. © 2002 American Institute of Physics.

Notes: Silicon crystals at room temperature employed as x-ray monochromators on synchrotron radiation beamlines, when subjected to high-power-density loading, suffer thermal distortions which compromise their x-ray diffraction efficiency and result in a reduction of the inherent brilliance of the synchrotron beam. At cryogenic temperatures however (below 150 K), silicon crystals suffer little or no thermal distortions under high-power-density loading. The design and implementation of a channel-cut silicon crystal monochromator which is cooled to as low as 50 K, using a commercial helium refrigerator and circulation system and a custom-designed heat exchanger for the monochromator crystal, are described. Test results have been obtained on the National Synchrotron Light Source X13B in-vacuum undulator beamline as well as the higher power X25 wiggler beamline. © 2002 American Institute of Physics.

Notes: The first chromatic hard x-ray interferometer with a large and variable path length difference (PLD), based on a variation of the all-Bragg Graeff–Bonse x-ray interferometer has been built and successfully tested. See W. Graeff and U. Bonse, Z. Phys. B 27, 19 (1977). Such a capability can be used for better beam coherence measurements and also opens up the possibility of Fourier transform spectroscopy in the x-ray regime. Going through this interferometer, the beam is split in two and then recombined, by a set of four Bragg reflections in a (+−−+) geometry. In order to incorporate a large variable PLD between the two beams, a small angle (1°) was partly cut into the mirror faces (middle two reflections) in one of the arms of the interferometer. The PLD thus varies depending on the incident beam location on the beamsplitter surface. In this design, a very large PLD (millimeters) is easily achievable and is limited only by the available size of the silicon crystal. A larger angular cut in the mirror surfaces will also increase the achievable PLD. The test consisted of measuring the interference fringes visibility as a function of the PLD. The fringes are obtained by measuring the exit beam intensity through small slits (25 μm), while a plastic wedge is inserted in one of the beam paths and translated in the direction of its thickness gradient. Based on these measurements, fringe visibility analysis was performed to give the transmitted beam coherence lengths. The results agree very well with the expected coherence values based on the interferometer's angular and spectral acceptances. © 2002 American Institute of Physics.

Notes: An x-ray phase retarder plate based on a diamond single crystal diffracting in the asymmetric Laue geometry has been characterized at the X25 wiggler beamline at the National Synchrotron Light Source. The forward diffracted (transmitted) beam, using the (111) Bragg planes in a 0.5 mm thick wafer with a (001) surface normal, was employed. A polarization analyzer based on a GaAs(111) crystal oriented to diffract the (222) and a different reflection simultaneously was used to determine the Stokes–Poincaré polarization parameters of the beam transmitted by the diamond phase plate, at several settings of the diamond about its (111) rocking curve. At 7.1 keV, the phase plate performed as expected and it was proven possible to produce, with the plate, an almost completely left- or right-handed circularly polarized x-ray beam from a linearly polarized incident beam. © 2002 American Institute of Physics.

Notes: A hard x-ray Fresnel zone-plate-based microprobe has been designed and integrated into a Newport kappa diffractometer for microdiffraction studies at the 2ID-D beamline at the Advance Photon Source. The microprobe employs 10 and 40 cm (focal length at 8 keV) zone plates to provide high and moderate focusing power, respectively. Each zone-plate assembly has two identical zone plates stacked together to provide higher focusing efficiency for higher energy (30 keV) applications. The mounting base of the microprobe is supported by the side of the base of the diffractometer at one end and the central table of the diffractometer at the other end, thus minimizing the instability of relative positions between the focal spot and the specimen. A x-ray focal spot size smaller than 360 nm and angular repeatability of the sample circles smaller than 0.001° have been demonstrated with this setup. © 2002 American Institute of Physics.

Notes: We have designed and fabricated, for the first time, a simple, compact, and low-cost electrostatic plasma lens based on the use of permanent magnets rather than an electrically driven solenoid to establish the magnetic field. Characteristics of the focused ion beam passed through the lens have been measured. Some of the beam characteristics depend strongly on the applied magnetic field strength and the precise form of the external potential distribution applied along the lens electrodes. The experimental results obtained at the Institute of Physics (Kiev) and at the Lawrence Berkeley National Laboratory (Berkeley) show that this plasma optical device can be used beneficially for focusing and manipulating moderate energy, large area, heavy metal ion beams. © 2002 American Institute of Physics.

Notes: The Spallation Neutron Source requires an ion source capable of delivering a high-current (∼50 mA) H− beam with a 6% duty cycle continuously for the three weeks between the scheduled maintenance periods. The cesium-enhanced, multicusp volume ion source under development on the integrated test facility at LBNL delivers H− ion currents up to 50 mA, increasing approximately linearly with the rf power. Initial experience using porcelain-coated copper antennas, however, indicates lifetimes will fall below the desired three-week period, mostly limited by antenna failures. In an effort to improve our understanding of the antenna limitations, we are in the process of developing an antenna test dome, which will allow us to visually observe and study the rf-initiated discharge at low-power levels. We hope to be able to test antennas for invisible defects by observing and measuring the onset of the discharge. In addition, we are planning to test different antennas. Results will be presented at the meeting. © 2002 American Institute of Physics.

Notes: Using the self-consistent, 2-1/2-dimensional particle-in-cell MAGIC code, based upon the explosive emission model, we have simulated the characteristics of the proton flux extracted from a planar magnetically insulated diode with a 200-mm-wide and an 8 mm anode-cathode gap. Results of numerical calculation, e.g., the spatial distributions of the extracted proton current density vs time and the spatial distribution of particles in diode gap are presented at a diode voltage of 300 kV with 40 ns pulse duration and an externally insulating magnetic field of 0–4Bcrit. With the increase of the magnetic field, the uniformity of the extracted proton flux is significantly improved; however, the maximum of the proton current density and one of the proton energy density decrease from 150 to 45 A/cm2 and from 1.0 to 0.3 J/cm2, respectively, when B varied from 0 to 4Bcrit. The effects of the magnetic field on uniformity of the extracted proton flux are discussed in this article. © 2002 American Institute of Physics.

Notes: A dc and pulsed-mode 75 keV proton injector has been developed and is used in characterization of a continuous-wave 6.7 MeV, 100 mA radio-frequency quadrupole (RFQ). The injector is used frequently at the full RFQ design power (100 mA, 6.7 MeV) where the RFQ admittance (1 rms, normalized) is 0.23 (π mm mrad). The injector includes a 2.45 GHz microwave proton source and a beam space-charge-neutralized, two magnetic-solenoid, low-energy beam-transport system. The design RFQ beam transmission of 95% has been demonstrated at 100 mA RFQ output current. © 2002 American Institute of Physics.

Notes: A new type of vacuum arc thruster in combination with an innovative power processing unit (PPU) has been developed that promises to be a high efficiency (∼15%), low mass (∼100 g) propulsion system for micro- and nanosatellites. This thruster accelerates a plasma that consists almost exclusively of ions of the cathode material and has been operated with a wide variety of cathodes. The streaming velocity of the plasma exhaust varies with cathode material, from a low of 11 km/s for Ti up to 30 km/s for Al, with a corresponding range of specific impulse from 1100 s for Ta to 3000 s for Al. Initiation of the arc requires only a few hundred volts due to an innovative "triggerless" approach in which a conductive layer between the cathode and the anode produces the initial charge carriers needed for plasma production. The initial starting voltage spike as well as the energy to operate the vacuum arc are generated by a low mass (〈300 g) inductive energy storage PPU which is controlled using +5 V level signals. The thrust-to-power ratio has been estimated to reach up to (approximate)20 μN/W. The vacuum arc thruster was tested at the Jet Propulsion Laboratory using W as cathode material. Experimental results are within 65% of the estimated values. © 2002 American Institute of Physics.

Notes: The plasma of the thruster plume was studied with oriented plane probes (these probes have only one face exposed to the plasma, either to the thruster, or to the opposite direction). The electron energy distribution function (EEDF) was determined from the second derivative of the probe curent. The electron density and effective electron temperature were determined by the integration of the EEDF and radial profiles of these parameters are reported. © 2002 American Institute of Physics.

Notes: Selecting the best neutron source for boron neutron capture therapy (BNCT) requires optimizing neutron beam parameters. This involves solving many complex problems. Safety issues related to the use of nuclear reactor in hospital environments, as well as lower costs have led to interest in the development of accelerator-driven neutron sources. The BNCT research programs at the Nuclear Departments of Pisa and Genova Universities (DIMNP and DITEC) focus on studies of new concepts for accelerator-based DT neutron sources. Simple and compact accelerator designs using relatively low deuteron beam energy, ∼100 keV, have been developed which, in turn, can generate high neutron yields. New studies have been started for optimization of moderator materials for the 14.1 MeV DT neutrons. Our aim is to obtain an epithermal neutron beam for therapeutic application at the exit end, with minimal beam intensity losses, the specific goal is to achieve an epithermal neutron flux of at least of 1×109 n/cm2 s at the beam port, with low gamma and fast neutron dose contamination. According to the most recent neutron BNCT beam parameters some moderating and spectrum shifter materials and geometrical configurations have thus far been tested, and neutron and gamma beam data at beam port have been computed. A possible beam shaping assembly model has been designed. This research demonstrates that a DT neutron source could be successfully implemented for BNCT application, with performance surpassing the minimum requirements stated above, using DT neutron sources with yields in the range 1013–1014 n/s. The latest Monte Carlo simulation results of an accelerator based facility which relies on a rf-driven DT fusion neutron generator will be presented. © 2002 American Institute of Physics.

Notes: To develop a type of negative ion source, we did fundamental research; namely, fine powders (∼1 mg) of CaH2, SrH2, or BaH2 deposited on a molybdenum ribbon were heated up to ∼1100 K; those active spots (Ca, Sr, or Ba) having low work function were produced by thermal decomposition (e.g., SrH2→Sr+H2); H2 (or D2) was introduced onto the spots; and the current (J−) of electron and that (IH− or ID−) of H− or D− emitted directly from the spots were measured simultaneously as a function of spot temperature (T) or pressure (PH or PD) of H2 or D2. Analysis of our data yields the results as follows. Below ∼850 K, H− is little produced from H2 because the spots are destroyed by a deactivation reaction (e.g., Sr+H2→SrH2). The spots of Ba are thermally stable even above 1000 K, where little deactivation occurs. IH− from the Ba spots kept at ∼1100 K increases up to ∼1 pA (after mass analysis) per 0.02 cm2 of emitting surface area, proportionally to PH increased up to ∼1 mTorr. As PD increases up to ∼0.1 mTorr, CaH2 (∼1000 K) gets a work function decrease (∼0.1 eV), yielding ID−(similar, equals)0.3 pA (∼15 pA/cm2). © 2002 American Institute of Physics.

Notes: A thermoelectric power (TEP) measurement technique in a self-clamped pressure cell is presented. Thermal and electrical contacts were glued to heaters by Stycast epoxy, which enhances thermal integration. The pressure effect of Chromel–Constantan and Chromel–AuFe0.07% thermocouples are compared to Chromel–Alumel thermocouples, which are known to be pressure insensitive between 4.2 and 300 K. The investigated thermocouples are found to have a small pressure effect; ∼±4% at maximum in the measured temperature and pressure range. Any pressure effect on Au wires was also found to be very small from the pressure-dependent TEP measurement of YBCO superconductor below Tc. © 2002 American Institute of Physics.

Notes: This article describes the design, start up, and some preliminary results of a rheometer that preshears the test fluid and measures its elongational viscosities. Preshearing takes place within a concentric cylinders arrangement. Fluid goes out from the lower part of the cylinders arrangement where an elongational flow is produced, by means of a vacuum chamber, which draws out the fluid filament. The influence of the preshearing history upon the elongational properties is analyzed. Data of elongational stress, uniaxial stretch rate, elongational normal stress difference, and apparent elongational viscosity are obtained. The rheometer design is based on a previous work by Sridhar and Gupta [Rheological Act 24, 207 (1985)]. Glycerin was used as the test fluid. Stretch rates up to 1250 s−1 were found. Trouton's ratios ranging from 2.6 to 3.6 were obtained. © 2002 American Institute of Physics.