bluuebunny/crossref_metadata_2025 huggingface dataset:
New way of body composition analysis using total body electrical conductivity method
Authors: Piasecki Wojciech , Koteja Pawel , Weiner January , Froncisz Wojciech
Published: July 2002

Traditional methods of measuring total body water and fat content of animals that require sacrificing specimens are generally unacceptable when endangered species, or large animal sizes, or humans are involved. These methods are also unsuitable for following changes of fat and water content in individuals. An alternative method, based on the nonresonant absorption of a rf electromagnetic field has been used for constructing a new body composition analyzer. As the electrical conductivity of lipids is approximately 20 times lower than that of lean tissues, the rf power absorbed by the animal provides information which enables one to calculate the lean body mass and total body water. The new instrument measures rf power absorbed by an animal by measuring the quality factor (Q) of the resonant circuit with an animal placed inside the coil. Numerical calculations of the rf power absorbed by a cylindrical object containing 0.9% NaCl aqueous solution have also been performed. Experimental values confirmed the calculated dependence of the absorbed power on the cylinder radius. The device built has been calibrated on 9 males and 11 females of laboratory mice. The amount of lipids was then measured by ether extraction. The relation between instrument reading, which is proportional to the power absorption, and lean body mass (LBM) or water mass (WM) was linear and highly significant: the simple regression coefficients of determination were 0.983 for LBM, and 0.990 for WM (p<0.001). It has been found that for an individual animal with a body mass ranging from 15.9 to 40.7 g, the accuracy of measurement was ±1.6 g for LBM and ±1 g for WM.
Transfer function of an ultralow frequency vibration isolation system
Authors: Liu Jiangfeng , Winterflood John , Blair David G.
Published: July 2002

We have measured the transfer function of the recently proposed folded pendulum which has a resonant period up to 66 s. Results confirm that the dynamic behavior of the folded pendulum closely approximates that of a simple pendulum of the same period. The system can provide a simple one-dimensional seismic isolation stage for laser interferometer gravitational wave antennas, as well as having application to very low frequency seismometers.
Frequency stabilization by frequency pulling for single-mode oscillation of He–Ne laser at maximum intensity
Authors: Yokoyama Shuko , Araki Tsutomu , Suzuki Norihito
Published: July 2002

Intense, frequency-stabilized single-mode laser sources are essential in precision distance measurements. We report a new scheme for stabilizing the oscillation of a three-mode laser so that a maximum output intensity can be realized. When one of the modes oscillates at its maximum intensity, the other two oscillate at each side of the central mode in the gain curve. The two intermode beats generated from the adjacent mode outputs are utilized to stabilize the laser frequency. Both the sum and the difference of the two beat frequencies vary because the frequency of each intermode beat varies with respect to cavity expansion via the phenomenon of ‘‘frequency pulling.’’ These secondary beat signals are utilized as control signals for stabilizing the laser output frequency. To evaluate the effectiveness of the proposed concept, we compared two possible stabilization techniques involving the addition and subtraction of beat frequencies from the perspective of design simplicity, reliability, and ease of operation. Our investigation has shown that stabilization using the difference of two intermode beat frequencies, is superior. Excellent frequency stability (instability=10−10) of the laser was achieved during experiments.
Device for high-resolution frequency-modulated absorption spectroscopy of jet-cooled molecules
Authors: Bethardy G. A. , Perry David S.
Published: July 2002

A device for high-resolution frequency-modulated absorption spectroscopy of jet-cooled molecules is described and demonstrated. Direct absorption spectra of jet-cooled molecules are recorded by multipassing an infrared laser beam through a free-jet expansion with all light rays perpendicular to the nozzle axis. In sliced-jet spectroscopy sub-Doppler resolution is obtained by inserting a small blade upstream from the laser crossing to obstruct molecules that would otherwise absorb at the center of the Doppler profile. Here the sliced-jet technique is extended by replacing the blade by a stainless-steel string vibrating at a frequency of about 10 kHz. Phase sensitive detection of the frequency-modulated absorption signal is accomplished with a lock-in amplifier. A resolution of 12 MHz is demonstrated using the modulated sliced-jet technique.
Thermal and deformation analyses of a cryogenically cooled silicon monochromator for high-heat-flux synchrotron sources
Authors: Wang Zhibi , Yun Wenbing , Kuzay Tuncer M. , Knapp Gordon , Rogers Shawn
Published: July 2002

The analytical results and design considerations for a cryogenically cooled advanced photon source (APS) silicon monochromator are presented. The high conductivity and low thermal expansion coefficient of silicon at cryogenic temperatures are advantages that are used to solve the high-heat-flux problem from undulator radiation. The APS monochromator features a machined slot with variable thicknesses below the surface. This configuration is designed to reduce absorption by the crystal and decrease the maximum temperature of the crystal. The transmitted power through the crystal is absorbed by a second element that can be cooled by standard cooling techniques. Different parameters and configurations are analyzed to maximize the performance of the monochromator and minimize the total absorbed power by the crystal.
A simple method for wavelength calibration of monochromators with a sine drive
Authors: Wang Qiuping , Zhang Yunwu
Published: July 2002

A general relation between the linear displacement and the rotation angle in a sine drive is described, from which a fitting method is proposed. This method has been used successfully for wavelength calibration of beamlines at the NSRL. It exhibits prominent features in beamline adjustment and wavelength calibration, especially for those monochromators which include more than one grating. By this method it is also convenient to obtain the structural parameters related to the wavelength scanning apparatus.
Side-cooled 1200 mm silicon x-ray mirrors with pneumatic benders
Authors: Pauschinger D. , Becker K. , Ludewig R.
Published: July 2002

This paper reports the successful design, fabrication, and testing of several side-cooled silicon and SiC (graphite) synchrotron mirrors (flat, spherical, and cylindrical) with a length of up to 1200 mm. The mirrors are equipped with support structures which allow the mirrors to be bent meridionally to cylinders with radii from infinity to 5000 m. Detailed metrology results are presented for the mirrors and the bending system. All mirrors will be installed at ESRF beamlines 8, 15, and 19.
The recent development of Bragg–Fresnel crystal optics. Experiments and applications at the ESRF (invited)
Authors: Snigirev A.
Published: July 2002

Bragg–Fresnel optics shows excellent compatibility with ESRF sources and is capable of obtaining monochromatic submicron focal spots with 108–109 photons/s in an energy bandwidth of 10−4–10−6 and in a photon energy range between 6–100 keV. Microprobe and microimaging techniques based on Bragg–Fresnel optics have been realized at the ESRF beamlines.
Prototype grooved and spherically bent Si backscattering crystal analyzer for meV resolution inelastic x-ray scattering
Authors: Blasdell R. C. , Macrander A. T.
Published: July 2002

The high-order backscattering reflections from single crystals of silicon have mrad rocking curve widths that can be exploited to produce meV energy-resolution focusing analyzer crystals for use in inelastic x-ray scattering experiments at third-generation synchrotron sources. The first generation of these analyzers has been limited in efficiency principally by slope and/or figure errors. We calculate the effect of slope errors on the theoretical energy resolution and focus spot size of a typical analyzer design using a ray-tracing code to ensure that there are no unforeseen contributions to the energy resolution and efficiency. We also present measurements of the slope errors of the atomic planes for a prototype, spherically bent, strain-relief grooved analyzer as proof that it is in principle possible to obtain the slope and figure error limits required for a high efficiency meV resolution backscattering crystal.
Obtaining three-dimensional height profiles from a two-dimensional slope measuring instrument
Authors: Irick Steven C. , Kaza R. Krishna , McKinney Wayne R.
Published: July 2002

The long trace profiler (LTP) was developed in order to measure the mid- and long-period variations in optical components for beamlines of high-brightness synchrotron sources. The LTP is a slope measuring instrument, and the optic under test is typically measured along a single tangential line, giving a two-dimensional profile. If a three-dimensional height profile (surface map) is desired, it is necessary to combine the integrated slopes of several measurements. A series of LTP measurements and a data processing method used to combine standard LTP data into a three-dimensional height profile are described. The measurement of a synchrotron beamline mirror and its three-dimensional height profile are presented.
Fabrication and testing of hard x-ray sputtered-sliced zone plate
Authors: Kamijo Nagao , Tamura Shigeharu , Suzuki Yoshio , Kihara Hiroshi
Published: July 2002

A sputtered-sliced hard x-ray zone plate has been made by the physical vapor deposition of alternating transparent and opaque layers onto a fine gold wire core of 50 μm diameter. The zone plate is designed to operate with a focal length of 124 mm at 8.05 eV and consists of 25 pairs of alternating Ag and C layers with a thickness of ∼40 μm along the wire axis. Using monochromized synchrotron x ray with an energy of 8.05 keV the minimum focal spot size attained for the first order focal beam was 2.3 μm in the vertical and horizontal directions, respectively. The light-collecting efficiency was determined to be ∼4%. The focal spot size obtained was substantially larger than the 1.2 μm φ spatial resolution predicted from the contradiction of the light source size.
An UHV-compatible fixed-exit two-crystal monochromator
Authors: Kirkland J. P. , Elam W. T.
Published: July 2002

Simplicity, symmetric design, variable energy range, and support for both sides of the crystals are features of a new fixed-exit crystal monochromator that has been designed, built, and tested. It is less complex; therefore it is less expensive to build, easier to understand, and easier to maintain. The design is a variation of the Cowan boomerang design. Most of the high-precision surfaces are bars ground in parallel. Crystals are supported on both ends by carriages with high-precision ball-bearing wheels. These bearings roll along the bars to carry the crystals and to actuate the rotation of the crystals. By supporting crystals on both sides, water-cooling and dynamic crystal bender systems can be incorporated without adversely affecting the crystal stability. The system is highly symmetric, with no preferred orientation for entrance and exit beams. Angular ranges, and therefore energy ranges, for the system are easily varied by changing the length of the boomerang arms. The system is compact, with an angular range of 80°–3.5° for theta fitting within a length of 840 mm. This angular range corresponds to an energy range of 2.0–30 keV for Si(111).
Cryogenic monochromator as a solution to undulator heat loads at third-generation synchrotron sources
Authors: Knapp G. S. , Rogers C. S. , Beno M. A. , Wiley C. L. , Jennings G. , Cowan P. L.
Published: July 2002

We have developed a new design for a cryogenically cooled monochromator employing a thin-crystal strategy which is capable of handling the central-cone power of the Advanced Photon Source’s undulator A at closed gap and at the full design current of 300 mA. We have designed and fabricated a Si (111) crystal which has a thin section where the x rays hit and has internal cooling channels. An Invar manifold has also been designed and it will be attached to the Si via In gaskets. We have done detailed modeling, both with approximate analytical and with finite element calculations. The results show that our design has negligible thermal strain even for closed gap operation.
Efficient extraction window for high-throughput x-ray lithography beamlines
Authors: Kuroda Kenichi , Kaneko Takashi , Itabashi Seiichi
Published: July 2002

An x-ray extraction setup with a double-window configuration (diamond and beryllium windows) is investigated for x-ray lithography beamlines using synchrotron radiation (SR) sources. A cylindrical frame for holding the Be foil greatly reduces the film thickness required to withstand the atmospheric helium pressure, but Be foil is subject to plastic deformation at temperatures above 250 °C. A thermal shield is therefore required upstream from the Be window. Testing the combination of a 1-μm-thick diamond film as the thermal shield and a 15-μm-thick Be foil as the vacuum separation window confirmed the excellent performance of this double-window setup even when the irradiation power was 8 W/cm2, which corresponds to a 500 mA storage current in the NTT SR ring (Super-ALIS: critical wavelength=17.3 Å).
Design of a compact varied-line space grating monochromator for enhanced flux at MAXLAB
Authors: Mancini Derrick C. , Nordgren Joseph , Wassdahl Nial , Andersén Walther , Nyholm Ralf
Published: July 2002

For soft x-ray fluorescence spectroscopy with selective energy excitation, it is desirable to have maximum flux at moderate resolution. A plane grating monochromator with varied line spacing can be used in the convergent beam of an ellipsoidal focusing mirror to provide moderate resolution with a large collection angle and minimum number of reflecting surfaces. We determine the design parameters for a varied-line-space grating monochromator to provide light in the 200–1000 eV range. The results of modeling are discussed with respect to the optimal choices of monochromator for our experimental requirements. A novel mechanical design is proposed for constructing the monochromator in a compact form with the minimum number of moving parts and alignments.
Commission of third-generation light sources (invited) (abstract)
Authors: Wrulich A.
Published: July 2002

World-wide, four third-generation light sources have been set in operation during the last few years, the ESRF, SRRC, ALS, and ELETTRA. An overview on the commissioning of these sources is given with the emphasis on the specific experience with ELETTRA.
Performance of the 1 m Seya–Namioka monochromator beam line at SRRC
Authors: Tseng P.-C. , Hsieh T.-F. , Song Y.-F. , Lee K.-D. , Chung S.-C. , Chen C.-I. , Lin H.-F. , Dann T.-E. , Huang L.-R. , Chen C.-C. , Chuang J.-M. , Tsang K.-L. , Chang C.-N.
Published: July 2002

The performance of the 1 m Seya–Namioka monochromator (1 m-SNM) beam line at SRRC has been measured and reached the designed goal. The beam line throughput (photon flux) has been measured by a calibrated silicon photodiode and is close to the theoretical values. The resolving power of this beam line has been measured from the studies of the core absorption of Ar and Ne and the Rydberg states of Mg vapor gas, and has reached the theoretical values. The improvement of the cooling system of the first mirror is also described.
Computer control of the SRC high-resolution beamline
Authors: Eisert David E. , Bissen Mark , Fisher Mike V. , Reininger Ruben , Stott John P. , Höchst Hartmut
Published: July 2002

We discuss the complexities of controlling the new high-resolution soft x-ray beamline at the University of Wisconsin Synchrotron Radiation Center. A monochromator at the heart of the beamline utilizes a combined rotation and translation of a variable line spaced grating to minimize major aberration terms. A rotational accuracy of 0.12 arcsec and a translational accuracy of 10 μm are required for the combined motions to obtain the desired resolution. A rotational resolution of better than 0.01 arcsec was achieved with the use of a laser interferometer and piezoelectric actuator for submicrometer feedback control. The translation control uses a linear encoder with a resolution of 0.1 μm and a motorized feedback loop. A calculation overhead of less than 100 μs for each movement was obtained by using a spline fit to approximate the rotational and translation positions to the required accuracy.
X-ray polarimetry with phase plates
Authors: Giles C. , Vettier C. , de Bergevin F. , Malgrange C. , Grübel G. , Grossi F.
Published: July 2002

Diamond crystals were used as quarter-wave plates (QWPs) and half-wave plates (HWPs) to produce and completely analyze circular and vertical linear polarization of monochromatic x rays from an undulator source (ID10) at the European Synchrotron Radiation Facility. The horizontal linear polarization state of the forward diffracted beam in the Bragg or Laue geometry was efficiently converted into circular (99%) and vertical polarization (97%) by tuning the crystal conveniently away from the Bragg peak. Also, the combination of two QWPs was used to obtain linear polarization at any desired azimuth (e.g., 95% at 45°). Further, the second QWP and the linear polarimeter were used to completely characterize the polarization state of the circularly polarized beam after the first QWP. High efficiencies at QWPs and HWPs and high transmitted intensity (40%) were achieved with the diamond crystal in the asymmetric Laue geometry.
A scanning x-ray microscope using circularly polarized radiation at the TRISTAN accumulation ring and its application to observation of ferromagnetic domains
Authors: Kagoshima Y. , Miyahara T. , Ando M. , Wang J.-D. , Aoki S.
Published: July 2002

A scanning x-ray microscope using circularly polarized radiation has been constructed at the beamline NE1B of the 6.5-GeV TRISTAN accumulation ring (AR). It uses a Fresnel zone plate as an x-ray focusing lens. Its spatial resolution has been evaluated to be ∼1.2 μm at the energy of 933 eV. Depending on the relative orientation between the photon spin and the local magnetization direction, the magnetic domains recorded in a piece of videotape have been successfully observed visually at the L2,3 absorption edges of cobalt. The contrast of the image arises from the magnetic circular dichroism in core-level photoemission of ferromagnets. The observed contrast was certainly reversed between L2 and L3 edges.
Magnets producing arbitrarily directed magnetic fields used for SR x-ray diffraction and a proposal for a novel insertion device
Authors: Nakajima Tetsuo , Yoshizawa Masami
Published: July 2002

After the manner of a goniometrical control of the incident beam and the crystal orientation by a four-circle goniometer, the strength and direction of the resultant magnetic fields produced by a set of three pairs of solenoids was goniometrically controlled by three bipolar electric-power sources. Two types of superconducting and normal Helmholtz-coil magnets were constructed. In the superconducting magnet, the coil constant is about 0.01259 TA−1 and the maximum magnetic field is about 0.5 T. The resultant maximum field is about 0.86 T in the [111] direction. In the normal magnet, the size of each coil is different. Each maximum field is up to about 337 Oe. Alternating- and direct-current magnetic fields applied to a crystal are able to vary from one direction [h1k1l1] to another [h2k2l2] while keeping parallel to an arbitrary curved surface. X-ray topographs of α-Fe-3%Si in magnetic fields swept in (110) from [002] via [22̄2], [11̄0], [22̄2̄], and [002̄] to [002] were taken using an N-type Helmholtz magnet. It is suggested that a coaxial serial connection of the two-dimensional astatic magnet with the above-mentioned specifications could be used as a new definitive-type insertion device, which could control the characteristics of polarized beams.
Dark-field imaging in hard x-ray scanning microscopy
Authors: Suzuki Yoshio , Uchida Fumihiko
Published: July 2002

Preliminary experiments on dark-field imaging in hard x-ray scanning microscopy have been performed with a wavelength tunable x-ray microprobe. A number of different detector geometries are used to detect diffracted x rays, reflected (and refracted) x rays, and scattered x rays. Although the dark-field signal is much weaker than the bright field (transmission) signal, it is still possible to detect low absorption contrast features. Experimental results obtained from test samples are presented.
Alkali Rb-doped C60: The movement of the valence band (abstract)
Authors: Haibin Pan , Pengshou Xu , Erdong Lu , Fengyuan Yang , Andong Xia , Xinyi Zhang , Guochang Zhang
Published: July 2002

Using synchrotron radiation light source, we have measured the photoemission spectra of undoped C60 and alkali Rb-doped C60 to reveal their electron structure. We observed a complex movement of the top of the valence band through the process of alkali Rb doping. When Rb is doped into C60, at first the spectrum moves to the high binding energy side for about 0.5 eV. As doping continues, the spectrum moves to the low binding energy side again. The spectrum moves back toward the original site by a small amount until the stoichiometry reaches about 1. This phenomenon has not been reported in other alkali doped C60 systems. We suggest the backward movement is due to the instability of the RbC60, Rb3C60, and other phases.
Magnetic field mapping system on the H-1 heliaca)
Authors: Shats M. G. , Rudakov D. L. , Blackwell B. D. , Sharp L. E. , Fedyanin O. I.
Published: July 2002

The H-1 heliac recently brought into operation is a medium-sized 3-field-period heliac with major radius R0=1 m, plasma mean minor radius 〈a〉≤0.2 m and a wide range of rotational transforms 0.6≤ι–(0)≤2.0. Electron beam mapping of the vacuum magnetic field was performed using new type of a fluorescent target (movable fluorescent rod array having a transparency about 98%). Up to 150–200 toroidal transits were observed at each electron gun position. The spatial resolution of the system was about 3 mm. Electron collector probes were used for monitoring the positions of the magnetic surfaces in different toroidal field periods. Visible paths of the electron beam due to the excitation of the background gas (p∼10−4 Torr) were used for identification of the toroidal transit numbers. This newly developed method gives an accuracy in measurement of the rotational transform of about 1.5%. Experimental surfaces and measured ι/ profiles show very good agreement with the computer model results.
Two-axis goniometer for reflectivity measurements of x-ray diffractors used in fusion researcha)
Authors: Peacock N. J. , Barnsley R. , Patel A. , O’Mullane M. , Singleton M. , Ashall J.
Published: July 2002

Quantitative measurements of the line and continua emissivities and the analyses of spectral line profiles are essential steps in the interpretation of the x-ray emission from high-temperature fusion plasmas. One method of placing the emissivities on an absolute basis is to use an absolutely calibrated spectrometer to record the data. The overall sensitivity of the spectrometer can be constructed in terms of the efficiencies of its separate components, the most intractable being Rc, the reflection integral of the diffractor. To this end, a new, compact, two-axis diffractometer, incorporating modern robotic technology, such as direct-drive servomotors with closed-loop operation from built-in arcsec optical encoders, has been constructed. Improved features of this double-axis goniometer include the use of fixed line-of-sight x-ray sources with the capability of operation in the (1,−1) parallel, nondispersive mode or the antiparallel, (1,+1), dispersive mode. The diffractometer is now being used to calibrate x-ray diffractors, filters, mirrors, and detectors associated with x-ray spectroscopy of fusion plasmas. At certain wavelengths, where line branching ratios involving visible transitions are available, the fusion plasma may itself be used as a transfer standard of x-ray luminosity, allowing an independent check on the diffractometer values of Rc. Applications to the analyses of impurity concentrations in tokamaks are described while future applications of the diffractometer to radiation damage studies of x-ray and optical components [Hill et al., Rev. Sci. Instrum. 63, 5032 (1992)] used in D-T burning plasma experiments are envisaged.
Microplasma object imaging spectroscopy by using zone plate surface structure on mica crystal
Authors: Erko A. I. , Panchenko L. A. , Pikuz S. A. , Mingaleev A. R. , Romanova V. M. , Shelkovenko T. A. , Faenov A. Ya. , Bryunetkin B. A. , Pikuz T. A. , Skobelev I. Yu.
Published: July 2002

A new method is proposed for obtaining spatially resolved multicharged ion spectra of microplasma sources with resolution better than 0.5 μm. The method is based on making a Bragg–Fresnel lens structure on a mica crystal surface. The lens was formed in a direction normal to the direction of dispersion and was used for the investigation of plasma created in nanosecond X pinch. The method may be used in studies of plasma heated by pico- and femtosecond laser radiation.
A differential-spectrum ion-energy analyzer with electrostatic slanted grids
Authors: Sakamoto Y. , Cho T. , Hirata M. , Yoshimura T. , Makino K. , Nakashima Y. , Yatsu K. , Tamano T. , Miyoshi S.
Published: July 2002

A novel end-loss ion-energy spectrometer is designed for plasma-ion diagnostics in open-ended plasma-confinement devices. This analyzer significantly upgrades a previous slanted grid end-loss analyzer (SELA) to essentially eliminate secondary-electron current, and to provide a differential-spectrum mode of operation, in addition to the usual integral-spectrum operation of gridded ion-energy analyzers. The upgraded SELA does not perturb the ambient magnetic field due to its electrostatic operation. Either the differential or integral spectra are obtained by a time sweep of grid voltages, collecting the ion current on a single-channel plate. Because the angular alignment of the SELA is not critical, it can be used as a spatially scannable diagnostic of ion-energy distributions and plasma potentials. It is characterized using computer simulations of ion trajectories, monoenergetic ion beams, and end-loss plasma from the world’s largest tandem mirror—GAMMA 10.
Methods for the measuring surface tritium inside TFTR using beta decay
Authors: Zweben S. J. , Johnson D. W. , Hill K. W. , Ku L. P. , LeMunyan G. , Loesser D. , Owens D. K. , Medley S. S. , Mueller D. , Timberlake J. , Wampler W. R. , Doyle B. L.
Published: July 2002

Three potential methods for evaluating the surface tritium content of the TFTR vacuum vessel are described, each based on a different technique for measuring the in situ beta emission from tritium. These methods should be able to provide both a local and a global assessment of the tritium content within the top ≊1 μm of the inner wall surface.
Helicon plasma sputtering system for fabrication of multilayer x-ray mirrors
Authors: Koike Masaki , Chiwaki Mitsukuni , Suzuki Isao H. , Kobayashi Naoto
Published: July 2002

A sputtering system which utilizes a pair of helicon plasma cathodes has been developed for the fabrication of multilayer x-ray mirrors. The helicon plasma cathode consists of a conventional dc magnetron cathode and a radio frequency coil for a helicon wave. Contamination of thin films fabricated with the system are examined using Rutherford backscattering spectroscopy and x-ray fluorescence analysis. W/C multilayers having 2d spacings of 28–63 Å have been formed on Si substrates.
Scientific progress and improvement of optics in the VUV range (invited)
Authors: Kunz C. , Voss J.
Published: July 2002

Optical elements need to be developed at least at the same pace as synchrotron radiation sources of the third generation. We are concerned here with the interrelationship between improved optical instruments and scientific progress. This relationship becomes especially clear in the development of new monochromators with higher resolution and large throughput. The availability of better mirrors and gratings is most important in this respect. Another field is microscopy. We shall be concerned here mainly with scanning microscopy in which the radiation is imaged with mirrors onto a small spot on the sample. The respective imaging with zone plates is the topic of another paper. A spot size of 0.1 μm and better is theoretically feasible with mirrors but it depends on much progress in the manufacturing of aspherical mirrors of high accuracy. We demonstrate mainly from our own results with a spot in the 1 μm range that it is worthwhile to make this effort.
Measurement of the magnitude of surface reactance
Authors: Kourov D. N. , Shcherbakov A. S.
Published: July 2002

A method for measurement of the magnitude of the imaginary part of conductor surface impedance is proposed. The method can be used when the sample sizes are much less than the wavelength. Placing the samples in the region of a sufficiently uniform ac magnetic field inside a cavity prevents the need for the mechanical replacement of a part of the cavity wall and hence uncontrolled change of the cavity geometry, which is known to inhibit measurements of the surface impedance’s imaginary part. To check the efficiency of the method, the imaginary part of the surface impedance of two doped semiconductors Ge–Sb were measured in the frequency range of 2.26–4.78 GHz at room temperature.
A 100 keV operation of a large vacuum-immersed H− ion source
Authors: Oka Y. , Kaneko O. , Takeiri Y. , Tsumori K. , Ando A. , Asano E. , Akiyama R. , Kawamoto T. , Kuroda T.
Published: July 2002

A large vacuum-immersed H− ion source has been operated on the negative-ion-based neutral beam teststand. The achieved level of the beam and the pulse duration in beam conditioning were limited by a high-voltage breakdown in the vacuum vessel. A baffle plate at grounded potential for shielding completely from the charged particles was successful. A beam with an energy of up to 102 keV and the H− ion current of 0.55 A were achieved for 0.29 s without the breakdown. The ion current of ∼1.5 A was accelerated in cesium-seeded operation. The corresponding ion current density was ∼7 mA/cm2. A magnetic filter (as Type I LV magnetic filter) on the plasma electrode was applied. The electron beam component which was extracted from the plasma source together with H− ions was found to be very reduced.
Automation of a torque magnetometer for measuring magnetic thin films
Authors: Tejedor M. , Fernandez A. , Cerdeira M. A.
Published: July 2002

An automated torque magnetometer for thin film measurements using the ‘‘45° method’’ has been developed and built. Very low sampling rates (2 Hz) in the control process are allowed by fitting on the sample holder a circular metallic piece that acts as an electromagnetic brake.
The production of high-duty-cycle, high-yield beams of highly charged ions with an electron beam ion source
Authors: Stockli Martin P.
Published: July 2002

High yields of highly charged ions are produced with electron beam ion sources (EBISs) operated in a batch or pulsed mode, yielding small duty cycles. An EBIS operated in a continuous, dc, or leaky mode can produce continuous, ‘‘dc’’ ion beams, although with substantially lower yields especially for the higher charge states. This article introduces the leaky batch mode and the dc batch mode of operation which combine the high duty cycles obtained with leaky or dc modes with the high yields of highly charged ions obtained with batch modes. The leaky batch mode produces ion beams with duty cycles as high as 90% with ion yields as high as 70% of the most efficient batch mode. The dc batch mode delivers constant intensity (dc) ion beams during 50% of the time with ion yields as high as 98% of the most efficient batch mode. When the dc batch mode is combined with the stretcher mode proposed by Becker, the dc batch mode will allow for dc ion beams of constant intensity with yields close to the most efficient batch mode.
Fiber optic velocity interferometer with very short coherence length light source
Authors: Levin L. , Tzach D. , Shamir J.
Published: July 2002

A novel fiber optic velocity interferometer for velocity measurements of moving surfaces has been developed and tested. The interferometer is based on optical fibers or fiber coupled components only and therefore is compact, portable, easy to align, and enables measurements in hard to reach locations. It also does not require a source of long coherence length (only a few wavelengths, regardless of the optical path difference or the surface displacement). This interferometer removes the directional ambiguity of the acceleration using a [3×3] optical coupler.
Thermal-wave measurement of thin-film thermal diffusivity with different laser beam configurations
Authors: Yu X. Y. , Zhang L. , Chen G.
Published: July 2002

This work investigates and compares three laser-based ac heating methods for measuring thermal diffusivity of free-standing thin-film structures. These methods employ a modulated laser beam as the heating source and a miniature thermocouple as the temperature sensor. Three laser beam configurations including uniform illumination, a line, and a point are utilized as the heating sources. Different models and systems are developed for these beam configurations. Samples studied include a GaAs/AlGaAs two-layer thin-film structure, a periodic GaAs/AlAs thin-film structure, and a silicon film. Both the phase and amplitude signals of the ac temperature rise of samples are used to derive their thermal diffusivities. It is found that the uniform illumination method is more susceptible to error than the other two configurations due to two-dimensional effects. Both the line and the point source configurations yield satisfactory results.
Cleanroom compatible anodization cell for 150 mm Si wafers
Authors: Bardwell Jennifer A. , LeBrun Les , Evans R. James , Curry Donald G. , Abbott Roger
Published: July 2002

A cleanroom compatible anodization cell for use with 150 mm Si wafers has been constructed and tested. The material of construction is polyvinylidene fluoride, Kynar■, with Chemraz■ (elastomeric polytetrafluoroethylene) O-rings used for sealing. The back contact is made through a dilute HF solution, thus eliminating the possibility for metallic contamination which exists for other forms of back contact. Pt electrodes immersed in the back contact and front contact solutions are the primary electrical connection sites. Ellipsometry, Fourier transform infrared spectroscopy (FTIR), and dilute HF etch rate experiments were used to characterize the as-grown and annealed anodic oxides produced in this cell. Ellipsometric thickness mapping showed excellent lateral oxide uniformity over the entire anodized area; the standard deviations were <2 Å (for oxides ≤100 Å in thickness), <6 Å (for oxides ≤400 Å in thickness), and <10 Å (for oxides <500 Å in thickness). The properties of the oxides, as evaluated by FTIR spectroscopy are essentially identical to those grown on small-area samples using conventional anodization with a metallic back contact.
Temperature-dependent sample holder for x-ray spectrometer
Authors: Jonnard P. , Chargelègue P. , Hombourger C. , Thirion J. , Vergand F.
Published: July 2002

We describe a temperature-regulated sample holder of the x-ray spectrometer IRIS. The refrigerator which cools the sample holder uses a closed helium gas cycle. Working temperatures from 70 to 320 K can be obtained when the electron beam is on. Tests demonstrate the ability of the system to produce high-resolution spectra.
Multiplexed single-photon counting. II. The statistical theory of time-correlated measurements
Authors: Suhling K. , McLoskey D. , Birch D. J. S.
Published: July 2002

We present the statistical theory governing the operation of multiplexed time-correlated single-photon counting (MUX-TCSPC) fluorometers which incorporate multiple detection channels and a single time-to-amplitude converter. The requirement to reject coincident counts in different detection channels leads to binomial photon counting statistics. The overall data collection probability is mapped out in terms of the ‘‘start’’ repetition rate, the number of detection channels, the ‘‘stop-to-start’’ rate ratio per detector, and the dead time. The overall collection probability is shown not to be proportional to the number of detection channels, but to be maximized at ∼0.37, which still compares very favorably with the equivalent pileup limited probability of ∼0.01 for a single detection channel. Excellent agreement with our theory is demonstrated for experimental data with 2 and 16 detection channels. Potential sources of errors when using MUX-TCSPC to record fluorescence anisotropy and spectra are described. The theory we describe provides a model for photon counting with multiple detection channels which is quite general and also applicable to other fields such as time-resolved imaging using photon migration in tissue and optical time-domain reflectometry.
A convenient modification to the Newport pulsed molecular-beam valve
Authors: Brock L. R. , Pilgrim J. S. , Robbins D. L. , Duncan M. A.
Published: July 2002

We describe a modification to Newport Corporation’s BV-100 double solenoid pulsed molecular-beam valve that replaces the Viton tip seal with an O-ring-based plug. This alteration produces the same characteristic short and cold gas pulses as the originally described beam valve without the difficulties associated with replacing the seal.
Microwave compatible electromagnetic valve for plasma deposition studies
Authors: Sanner Mark A. , Park Jin Y.
Published: July 2002

A microwave compatible electromagnetic valve capable of discharging saturated vapors in vacuum for shock wave formation and subsequent pulsed plasma deposition is presented. The valve discharges vapors of 1–5 atm and 75 °C with open duration times of 36–178 μs into vacuum. A theoretical model describing rarefaction wave motion coupled with a valve dynamic model was used to determine critical open duration time required for driving a shock wave in the experimental system. Valve design, operating characteristics, and rarefaction wave dynamics for H2, He, Ar, and CO2 internal to the valve are described.
The equivalence of digital rate meter algorithms
Authors: Arandjelović V. Dj. , Koturović A. M.
Published: July 2002

By introducing the ratio of the measurement time intervals of digital rate meter algorithms as an additional parameter, the concept of response-time equivalence for digital rate meter algorithms, linear and exponential, has been generalized to arbitrary measurement time intervals of both algorithms. From the generalized response-time-equivalence relation the bounds to values of the basic parameters of these algorithms, determining the set of parameter values where the concept of the generalized response-time equivalence applies, have been analyzed. An examination of the ratio of the steady-state statistical fluctuations of the current results of these two algorithms showed that it was possible to establish the conditions for the generalized statistical-fluctuations equivalence of the two algorithms. Finally, the conditions for equal response times and equal steady-state statistical fluctuations at arbitrary count rates, defined as the conditions of complete equivalence, have been determined.
Voltage controlled current source to avoid common mode interferences
Authors: Burin P. Payet , Pfleiderer C.
Published: July 2002

We report on a method to avoid common mode related interferences by means of a voltage controlled current source. Our technique is discussed for the case of experimental investigations involving very low signal levels, as encountered in the study of small metallic samples, at very low temperatures.
Selection of targets and ion sources for radioactive ion beam generation at the Holifield Radioactive Ion Beam Facilitya)
Authors: Alton G. D.
Published: July 2002

In this article, we describe the performance characteristics for a selected number of target ion sources that will be employed for initial use at the Holifield Radioactive Ion Beam Facility as well as prototype ion sources that show promise for future use for radioactive ion beam applications. A brief review of present efforts to select target materials and to design composite target matrix/heat-sink systems that simultaneously incorporate the short diffusion lengths, high permeabilities, and controllable temperatures required to effect fast and efficient diffusion release of the short-lived species is also given.
Equipment for in situ resistivity and x-ray diffraction studies during ion implantation at temperatures between 4 K and 1270 K
Authors: Königer A. , Hammerl C. , Zander W. , Rauschenbach B. , Stritzker B.
Published: July 2002

An instrument is presented which was designed for comprehensive in-situ analysis of phase formation and transformation during the ion implantation process. An implanter end station with heatable He-cryostat as a sample holder was built. A temperature range from 4 to 1270 K is covered by the sample holder so that temperature can be varied during implantation or subsequent annealing in high vacuum. Both x-ray diffraction and four-point resistivity measurement are installed as in-situ investigation techniques. In this way a detailed study of structural changes and defect kinetics during ion bombardment is now possible. The whole instrument has been successfully tested. Examples of carbon ion implantation in titanium and iron are given.
Photon beam diagnostics and characterization tools (invited, abstract)
Authors: Yun W.
Published: July 2002

Photon beam diagnostics and characterization are very important to the production and effective use of synchrotron x-ray beams. Proper diagnostic tools, techniques, and procedures are useful not only for initial commissioning of a beamline but also for its maintenance. In some cases, it is essential to have some beam diagnostic and characterization capabilities as an integral part of the overall beamline design. On-line characterization tools can also assist the user in specimen alignment and in setting up experiments. Important parameters of a photon beam include absolute flux, energy spectrum, coherence properties, spatial and angular distribution, polarization state, timing structure, and position and angular stability. A separate workshop focuses on the timing structure, and the conference has an invited talk on polarization characterization. Consequently, this workshop concentrated on the following two topics: • Measurement of the insertion-device and bending-magnet source characteristics: particle beam emittance, spectrum, and angular distribution. • Characterization of the radiation at the end of a beamline: absolute flux, resolution, spot size, and higher-order content. Simple, inexpensive techniques for photon beam characterization were emphasized. The workshop format included presentations by invited speakers with extensive experience at various synchrotron facilities, invited presentations, and general discussion. Time was also available for general discussion.
Inelastic nuclear resonant scattering at the Advanced Photon Source (invited)
Authors: Sturhahn W. , Toellner T. S. , Quast K. W. , Röhlsberger R. , Alp E. E.
Published: July 2002

It is demonstrated how inelastic nuclear resonant scattering can be used for the investigation of lattice dynamics. The required instruments are explained. The feasibility of measuring a variety of nuclear resonances is discussed with respect to the synchrotron radiation intensity at the Advanced Photon Source.
The multicrystal modular spectrometer for x-ray diffraction studies using SR
Authors: Kovalchuk M.V. , Kreines A.Ya. , Shilin Yu.N. , Shishkov V.A. , Kazimirov A.Yu.
Published: July 2002

We suggest a set of elements united in the modular x-ray spectrometer to easily implement multiaxis, multipurpose x-ray diffraction schemes, multiple-diffraction layouts with two-dimensional collimation of the incident beam, surface diffraction schemes, and experiments with various modifications of the x-ray standing wave method. The main elements of the spectrometer are: the one-circle goniometer with the vertical axis, the multicircle research goniometer, and different slit systems. All units except the multicircle goniometer can be mounted on two parallel optical guides. The multicircle goniometer is a stand-alone unit consisting of an Eulerian cradle mounted on a two-circle goniometer. All rotations are driven by stepping motors via worm gears. On axes where fine (to 0.1 arc sec or less) angular positioning is desirable, torsion-element-based rotation is used; it is driven via piezo drivers. A program package was developed to control the experiments. The software is based on the modular principle providing for fast implementation of application programs suited for specific x-ray diffraction methods. The results of multiple-diffraction studies with the use of the instrument are presented.
Anomalous small angle x-ray scattering study of layered silicate clays containing Ni(II) and Er(III)
Authors: Thiyagarajan P. , Carrado K.A. , Wasserman S.R. , Song K. , Winans R. E.
Published: July 2002

These studies concern the synthesis of heterogeneous catalysts and the incorporation of heavy metals in trapping media. The Ni(II) containing clays were synthesized at 200 °C whereas those containing Er(III) were ion-exchanged natural clays. For the first system, ASAXS data were measured at 5 different energies near the Kα edge of Ni at three different reaction times: unreacted, 4 hrs, and 15 hrs when the crystallization is essentially complete. The data for the unreacted sample showed no correlations for a lamellar particle, while that reacted for 4 hrs indicated the evolution of lamella, and the crystallized sample (15 hrs) exhibited much larger lamellar correlations. Systematic variations are seen in the data for the 4 hr and 15 hr samples that are due to the anomalous scattering from the ordered Ni atoms in the layered silicates. The erbium study provides the first scattering measurements of heavy metal ion solvation and migration in clays, which has implications for both catalysis and environmental issues. Systematic energy-dependent variations in the signals near the LIII edge of Er are observed for the hydrated sample but not for the ‘‘dry’’ as-prepared sample.
High-resolution electric-field-induced second-harmonic generation with ultrafast Ti:sapphire laser
Authors: Wu Marvin H. , Clays Koen , Persoons André
Published: July 2002

The technique of electric-field-induced second-harmonic generation (EFISHG) has been extended by use of a femtosecond, quasi-cw laser pump source. The effects of ultrashort pulse widths on the coherent EFISHG process have been examined and the analysis procedure used for nanosecond pulse EFISHG measurements is found to be suitable for femtosecond measurements in off-resonant regions. A convenient method for measurement of the group velocity mismatch between the fundamental and second-harmonic pulses in solutions has also been developed to accurately describe the femtosecond EFISHG process. Phase-sensitive detection of the modulated second-harmonic signals results in improvements in accuracy and sensitivity over existing nanosecond pulse experiments. This has been demonstrated with a measurement of Γ(−2ω; ω, ω, 0) of an organic molecule, 4-nitroanisole.