bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of Fresh Frozen Plasma with a Standardized Serum Protein Solution Following Therapeutic Plasma Exchange in Patients with Autoimmune Disease: A Prospective Controlled Clinical Trial
Authors: Keller E. , Beeser H. , Peter H.H. , Arnold A. , Kotitschke R.
Published: July 2002

abstract: The aim of the study was the comparison of the influence of fresh frozen plasma (FFP) (Freiburg, Germany) and Biseko, Biotest Pharma GmbH (Dreieich, Germany), as a plasma substitute (a standardized, virus inactivated human serum protein solution) on the coagulation factors, inhibitors, proteins, and complement factors in the plasma of autoimmune disease patients following membrane plasma separation. Patients (n = 24) with autoimmune disease were randomized to receive either FFP or Biseko for membrane plasma separation therapy. During each plasma exchange, 100% of the plasma volume was replaced by the respective substitute. Plasma exchange volume was performed once daily for 3 days. Target test parameters of the coagulation system were fibrinogen, fibrinopeptide A, factor VIII (FVIIIC), von Willebrand factor antigen (vWFAg), partial thromboplastin time (PTT), thromboplastin time (Quick value), and antithrombin (AT III). The immunoglobulins were IgG, IgA, and IgM and C‐reactive protein (CRP). The thrombocytes were platelet factor 4 (PF4), and complement factors were C3 and C4. Biseko was well tolerated with 1 mild adverse drug reaction (ADR) (n = 1) while FFP gave rise to ADR on 7 occasions (n = 4). Statistically significant differences in the 2 groups were observed for fibrinogen, PTT, Quick value, and AT III. From the clinical point of view, all fluctuations and differences in parameter levels remained clinically silent. The differences had no clinical consequences. Reflecting on a potential decrease in the risk of infections in comparison to FFP therapy and the lower rate of adverse drug reactions, it is possible to postulate an advantage of Biseko for plasma exchange therapy.
Local Induction of a Mycorrhiza‐Specific Class III Chitinase Gene in Cortical Root Cells of Medicago truncatula Containing Developing or Mature Arbuscules
Authors: Bonanomi A. , Wiemken A. , Boller T. , Salzer P.
Published: July 2002

Abstract: A class III chitinase gene, Mtchitinase III‐3, has been found to be induced in roots of Medicago truncatula specifically upon colonization by the arbuscular mycorrhizal fungi Glomus mosseae and Glomus intraradices. Here we show by in situ hybridization techniques that Mtchitinase III‐3 is only expressed in cortical root cells containing arbuscules formed by either of the fungi. Transcripts of Mtchitinase III‐3 were detected in cells containing developing as well as mature arbuscules. They were absent from cells adjacent to arbuscule‐containing cells, from cells in contact with intraradical hyphae and from cortical cells in non‐colonized areas of the root. These results indicate that the product of the Mtchitinase III‐3 gene has a role within individual cortical cells during formation and functioning of arbuscules.
Anwendbarkeit des Breast Imaging Reporting and Data System (BI-RADSTM) auf die klinische Mammographie des Mannes
Authors: Bock K. , Iwinska-Zelder J. , Duda V. F. , Bonwetsch C. , Rode G. , Hadji P. , Klose K.-J. , Schulz K.-D.
Published: July 2002

Ziel: In der apparativen Diagnostik dient die Einführung von Standards der Qualitätssicherung. Das Breast Imaging-Reporting and Data System (BI-RADSTM) des American College of Radiology standardisiert den Sprachgebrauch in der Befundbeschreibung, die Befundbewertung und die resultierenden Empfehlungen in der Mammographie. Unser Interesse galt der Frage, inwieweit dieses System der Kategorisierung von Screening-Mammographien der Frau übertragbar ist auf klinische Mammographien des Mannes. Begrenzen Anatomie und Physiologie der männlichen Brustdrüse im Vergleich zur weiblichen die Übertragbarkeit mammographischer Evaluationskriterien?

Methoden: Von 160 retrospektiv durch 4 unterschiedlich erfahrene Untersucher evaluierten klinischen Mammographien des Mannes konnten 36 Fälle mit histologischen Befunden korreliert werden. Letztere bilden das dieser Studie zugrunde liegende Kollektiv. Hierunter fanden sich typischerweise überwiegend Gynäkomastien, aber auch 4 invasiv duktale Karzinome, 1 Leiomyosarkom und 1 duktales Carcinoma in situ.

Ergebnisse: Durch Klassifikation nach BI-RADSTM (3rd Edition 1998) ließen sich alle Fälle invasiver Malignität in die Klassen 4 und 5 einordnen unabhängig vom Grad der Erfahrenheit des Untersuchers.

Schlussfolgerung: Die BI-RADSTM-Klassifikation ist auf die Bewertung von klinischen Mammographien des Mannes übertragbar. Kenntnisse geschlechtsspezifischer Charakteristika in der Bildgebung erhöhen die Spezifität bei gleichbleibend hoher Sensitivität.
Controllable reduction of critical currents in YBa2Cu3O7−δ films
Authors: White Alice E. , Short K. T. , Dynes R. C. , Levi A. F. J. , Anzlowar M. , Baldwin K. W. , Polakos P. A. , Fulton T. A. , Dunkleberger L. N.
Published: July 2002

The critical currents in high quality thin films of the high Tc superconductor, YBa2Cu3O7−δ, can be controllably reduced by orders of magnitude using ion irradiation. This reduction in critical current occurs without substantial decrease in Tc or increase in room-temperature resistivity. Using this technique, we have fabricated weak links that exhibit an ac Josephson effect at 77 K.
Structural properties of As-rich GaAs grown by molecular beam epitaxy at low temperatures
Authors: Kaminska M. , Liliental-Weber Z. , Weber E. R. , George T. , Kortright J. B. , Smith F. W. , Tsaur B-Y. , Calawa A. R.
Published: July 2002

GaAs layers grown by molecular beam epitaxy (MBE) at substrate temperatures between 200 and 300 °C were studied using transmission electron microscopy (TEM), x-ray diffraction, and electron paramagnetic resonance (EPR) techniques. High-resolution TEM cross-sectional images showed a high degree of crystalline perfection of these layers. For a layer grown at 200 °C and unannealed, x-ray diffraction revealed a 0.1% increase in the lattice parameter in comparison with bulk GaAs. For the same layer, EPR detected arsenic antisite defects with a concentration as high as 5×1018 cm−3. This is the first observation of antisite defects in MBE-grown GaAs. These results are related to off-stoichiometric, strongly As-rich growth, possible only at such low temperatures. These findings are of relevance to the specific electrical properties of low-temperature MBE-grown GaAs layers.
Direct evidence for self-annihilation of antiphase domains in GaAs/Si heterostructures
Authors: Ueda O. , Soga T. , Jimbo T. , Umeno M.
Published: July 2002

The nature and behavior of antiphase boundaries in GaAs/Si heterostructures using GaP, GaP/GaAsP, and GaAsP/GaAs strained-layer superlattices as intermediate layers have been studied by transmission electron microscopy. The antiphase domains are found to be very complicated three-dimensional polygons consisting of several subboundaries in different orientations. Self-annihilation of antiphase domains during crystal growth of GaAs on (001) 0.4° off or (001) 2° off Si substrates is directly observed for the first time through plan-view and cross-sectional observations. Based on these findings, a mechanism of annihilation of these domains is presented.
Bessel beam ultrasonic transducer: Fabrication method and experimental results
Authors: Hsu D. K. , Margetan F. J. , Thompson D. O.
Published: July 2002

We report experimental results from a first-of-a-kind ultrasonic transducer that generates a beam with a Bessel function profile. Using a technique of nonuniform poling, an axially symmetric Bessel function pattern is ‘‘polarized into’’ a piezoelectric ceramic element. The resulting circular-disk transducer has the usual full-plating electrode configuration, but produces an ultrasonic beam with a radial displacement profile approximating that of the Bessel function J0 (r), both in amplitude and in phase. The radiation field of a 1-in.-diam, 2.25 MHz Bessel transducer mapped out with a point probe shows good agreement with calculated results using a Gauss-Hermite model. Bessel transducers are of particular interest in attempts to achieve ‘‘diffractionless’’ beams.
Observation of Maker fringes and estimation of χ(3) using picosecond nondegenerate four-wave mixing in AlGaAs waveguides
Authors: Le H. Q. , Bossi D. E. , Nichols K. B. , Goodhue W. D.
Published: July 2002

Nondegenerate four-wave mixing experiments have been conducted in Al0.2Ga0.8As ridge waveguides, using picosecond laser pulses. Maker fringes due to phase-matching requirements were clearly observed, and phase-matched nondegenerate mixing was achieved by utilizing the waveguide geometrical birefringence. Conversion efficiency up to 5×10−3 for a coherent interaction length of 3 mm was obtained. The observed third-order nonlinear susceptibility χ(3)(ω3=ω1+ω1−ω2) does not display any strong resonances and exhibits a relaxation time shorter than 10 ps. From these measurements it is inferred that ‖χ(3)1111‖≥8×10−11 esu, and ‖χ(3)1111/χ(3)2112‖=2.4±0.3 for ω1 and ω2≊1480 meV/ℏ.
Model describing phosphorus diffusion gettering of transition elements in silicon
Authors: Schröter W. , Kühnapfel R.
Published: July 2002

We give experimental evidence for cobalt in silicon that each of the processes defining phosphorus diffusion gettering (PDG), i.e., (1) P doping by in-diffusion and (2) SiO2 growth, achieves moderate gettering, while the cooperation of the two processes leads to strong gettering of cobalt. In a tentative model, gettering is attributed to the coupling between local currents of silicon self-interstitials, which are generated during PDG, and 3d impurities on substitutional sites.
Precise measurements of oxygen content: Oxygen vacancies in transparent conducting indium oxide films
Authors: Bellingham J. R. , Mackenzie A. P. , Phillips W. A.
Published: July 2002

High precision electron probe microanalysis (EPMA) has been used to measure the correlation of oxygen deficiency with carrier concentration in thin films of amorphous indium oxide. This has shown that there are ten times as many oxygen vacancies as would be expected from the carrier concentration measurements, giving a doping efficiency of 0.1. It is therefore clear that the doping mechanism is more complex than the usual picture of every oxygen vacancy producing two free electrons.
Chemical vapor deposition of copper from 1,5-cyclooctadiene copper(I) hexafluoroacetylacetonate
Authors: Reynolds Scott K. , Smart Christopher J. , Baran Emil F. , Baum Thomas H. , Larson Carl E. , Brock Phillip J.
Published: July 2002

We have studied the chemical vapor deposition of copper from 1,5-cyclooctadiene Cu(I) hexafluoroacetylacetonate, a moderately volatile yellow cystalline solid. It yields pure copper by pyrolytic decomposition at 150–250 °C, produces copper films with near bulk resistivity, and has the advantage of being air stable at room temperature.
Efficient visible electroluminescence from highly porous silicon under cathodic bias
Authors: Canham L. T. , Leong W. Y. , Beale M. I. J. , Cox T. I. , Taylor L.
Published: July 2002

Visible electroluminescence (EL) has been obtained from porous silicon cathodically biased in an aqueous electrolyte containing either the persulphate or the peroxide ion. EL efficiencies of up to 0.1% have been obtained from porous silicon formed on both n-type and p-type substrates for the application of only a few volts bias. In subdued lighting, the EL is easily visible to the naked eye at excitation densities of 0.1 W cm−2. EL is obtained only from porous silicon capable of giving photoluminescence (PL); the EL and PL spectra are broadly similar in width and peak wavelength. The EL spectra are reversibly shifted to shorter wavelengths as the magnitude of the bias is increased. In contrast with the previously reported EL under anodic conditions, this cathodic EL process does not irreversibly oxidize the porous silicon skeleton.
Thermomechanical data storage using a fiber optic stylus
Authors: Hoen S. , Mamin H. J. , Rugar D.
Published: July 2002

We have developed a simple and fast surface modification technique for possible data storage applications. Writing is accomplished by heating the metallized tip of a tapered optical fiber with microsecond laser pulses. The heated tip, which is in contact with a polycarbonate substrate, creates a nanoindentation. Deflections of this same tip are used to detect the written marks, as in atomic force microscopy. The marks have sharp edges with 10%–90% transition widths of 0.2 μm, and have been written with laser pulses as short as 5 μs at repetition rates of 50 kHz. Readback has been performed over 300 kHz on a spinning sample. Substantial improvements in mechanical response and wear properties are seen compared to micromachined cantilevers.
Atomic ordering in molecular beam epitaxial InAsySb1−y natural strained layer superlattices and homogeneous layers
Authors: Seong Tae-Yeon , Booker G. R. , Norman A. G. , Ferguson I. T.
Published: July 2002

Transmission electron microscope studies were made of CuPt-type ordering in molecular beam epitaxial InAsySb1−y natural strained layer superlattices and homogeneous layers grown at temperatures in the range 295–470 °C. Ordering occurs with a maximum at a growth temperature of 370–400 °C, individual (1̄11) and (11̄1) ordered domains up to 10 nm in size are present, and there is a modulation of periodicity 3 d110 within the layers, where d110 is the (110) lattice spacing. The latter correlates with a [2×3] atomic surface reconstruction present during growth.
Heteroepitaxial growth of Ba1−xSrxTiO3/YBa2Cu3O7−x by plasma-enhanced metalorganic chemical vapor deposition
Authors: Chern C. S. , Liang S. , Shi Z. Q. , Yoon S. , Safari A. , Lu P. , Kear B. H. , Goodreau B. H. , Marks T. J. , Hou S. Y.
Published: July 2002

Epitaxial Ba1−xSrxTiO3(BST)/YBa2Cu3O7−x heterostructures with superior electrical and dielectric properties have been fabricated by plasma-enhanced metalorganic chemical vapor deposition (PE-MOCVD). Data of x-ray diffraction and high resolution transmission electron microscopy showed that 〈100〉 oriented Ba1−xSrxTiO3 layers were epitaxially deposited on epitaxial (001) YBa2Cu3O7−x layers. The leakage current density through the Ba1−xSrxTiO3 films was about 10−7 A/cm2 at 2 V (about 2×105 V/cm) operation. Moreover, the results of capacitance-temperature measurements showed that the PE-MOCVD Ba1−xSrxTiO3 films had Curie temperatures of about 30 °C and a peak dielectric constant of 600 at zero bias voltage. The Rutherford backscattering spectrometry and x-ray diffraction results showed that the BST film composition was controlled between Ba0.75Sr0.25TiO3 and Ba0.8Sr0.2TiO3. The structural and electrical properties of the Ba1−xSrxTiO3/YBa2Cu3O7−x heterostructure indicated that conductive oxide materials with close lattice to Ba1−xSrxTiO3 can be good candidates for the bottom electrode.
Electrical properties of heavily Si-doped (311)A GaAs grown by molecular beam epitaxy
Authors: Agawa K. , Hirakawa K. , Sakamoto N. , Hashimoto Y. , Ikoma T.
Published: July 2002

We have systematically studied the electrical properties of heavily Si-doped GaAs grown on the (311)A GaAs surfaces by molecular beam epitaxy. It is found that the conduction type drastically changes from p type to n type with decreasing growth temperature at a critical temperature of ∼430 °C for uniform doping and ∼480 °C for the δ-doping case, with the transition temperature width as narrow as ∼50 °C for both cases. The highest hole density obtained for uniformly doped layers was 1.5×1020 cm−3, while for δ-doped layers a sheet hole density as high as 2.6×1013 cm−2 was achieved, which is the highest sheet hole density ever reported for δ-doped p-type GaAs.
Nonlinear optical studies of a fluorinated poled polyimide guest-host system
Authors: Hubbard S. F. , Singer K. D. , Li F. , Cheng S. Z. D. , Harris F. W.
Published: July 2002

We report on poling of a low dielectric constant preimidized fluorinated fully aromatic guest-host polyimide nonlinear optical material including thermal stability of optical nonlinearities and waveguiding properties. We measured a second-harmonic coefficient (d33=4.9±0.5 pm/V at 1217 nm fundamental wavelength) which is accurately predicted by a thermodynamic model of poled polymers. The optical nonlinearity of a poled sample was thermally stable at 80 °C for over 300 h. Films were observed to have negative birefringence. Optical losses for slab waveguides in lowest order TE and TM modes were ≥7.7 dB/cm for doped waveguides at 800 nm wavelength and increased after poling.
Bias dependent recovery time of all-optical resonant nonlinearity in an InGaAsP/InGaAsP multiquantum well waveguide
Authors: Day I. E. , Snow P. A. , Penty R. V. , White I. H. , Grant R. S. , Kennedy G. T. , Sibbett W. , Davies D. A. O. , Fisher M. A. , Adams M. J.
Published: July 2002

The refractive nonlinearities due to bandfilling and the plasma effect in a multiquantum well buried heterostructure semiconductor waveguide under reverse bias are probed using self-phase modulation techniques. Modeling of the self-phase modulation has allowed the magnitude of the phase modulation and nonlinearity recovery time constant to be extracted. π radians phase shift has been obtained for a coupled pulse energy of 32 pJ. The nonlinearity recovery time constant is 18±3 ps for an applied field of 34 MV m−1, limited by thermionic emission from the quantum wells.
Thermoelectric figure of merit of superlattices
Authors: Sofo J. O. , Mahan G. D.
Published: July 2002

We calculate the electrical conductivity, thermopower, and the electronic contribution to the thermal conductivity of a superlattice, with the electric field and the thermal gradient applied parallel to the interfaces. We include the tunneling between quantum wells. The broadening of the lowest subband when the period of the superlattice is decreased produces a reduction of the thermoelectric figure of merit. However, we found that a moderate increase of the figure of merit may be expected for intermediate values of the period, due to the enhancement of the density of states produced by the superlattice structure.
Apparatus for measuring the stopping power of active materials evaporated i
n s
i
t
u and characterized by Auger electron spectrometry and Rutherford backscattering
Authors: Semrad D. , Bauer P. , Eder K. , Obermann W.
Published: July 2002

An ultrahigh-vacuum scattering chamber working in the low 10−9-mbar range is described. It is attached to a standard O-ring sealed beam transport system of an electrostatic accelerator. Twelve targets can be prepared in situ, one by one, by evaporating the material onto backings, which are mounted on tiltable target holders on a wheel. Backscattering spectra are obtained from these targets and the stopping cross section is deduced from their widths. A cooled high-resolution surface barrier detector is used for this purpose. The integral concentrations of light impurities in the target are obtained using Rutherford backscattering (RBS), whereas Auger electron spectrometry (AES) together with a sputtering device is used to determine the depth composition. As a test of the assembly we determined the stopping power of aluminum for protons and deuterons, respectively. The results are compared to published tables based upon fits to experiments. The influence of impurities on the result is discussed for an aluminum target prepared under standard evaporation conditions.
Time domain all-optical demultiplexing with a semiconductor directional coupler
Authors: Villeneuve A. , Mamyshev P. , Kang J. U. , Stegeman G. I. , Aitchison J. S. , Ironside C. N.
Published: July 2002

We report the demonstration of demultiplexing of 150 fs pulses, without pulse breakup, in an AlGaAs nonlinear directional coupler operated at photon energies below half the band gap energy of AlGaAs.
Nd:YAG laser microprobe system for Fourier-transform ion cyclotron resonance mass spectrometry
Authors: Brenna J. T. , Creasy W. R. , McBain William , Soria Cesar
Published: July 2002

An optical system has been interfaced to a commercial Fourier-transform ion cyclotron resonance mass spectrometer to facilitate laser microprobe mass spectrometry. The system allows a 266-nm laser beam to be focused and directed onto a specimen surface near an ICR trap plate. Reflected light is used to view the specimen in a reflected light microscope mode. Spatial resolution of the reflected light microscope, and laser microprobe spot diameter are 5–8 μm and are limited by the working distance of the objective lens. A novel specimen translation mechanism was constructed which overcomes difficulties associated with positioning a specimen in a high magnetic field. An interface system based on an IBM PC-AT was developed to coordinate experimental sequences between the ICR and laser.
Measurement of magnetic fluctuations by O→X mode conversion
Authors: Vahala Linda , Vahala George , Bretz N.
Published: July 2002

The possibility of measuring magnetic fluctuations in a fusion plasma is considered by examining the O–X mode conversion. Under certain conditions and with good angular resolution, this mode conversion can be attributed to the presence of magnetic fluctuations even though the level of these fluctuations is much lower than that of density fluctuations. Some nonideal effects such as mode polarization mismatch at the plasma edge are also discussed.
Ultrahigh vacuum chamber for synchrotron x-ray diffraction from films adsorbed on single-crystal surfaces
Authors: Dennison J. R. , Wang S.-K. , Dai P. , Angot T. , Taub H. , Ehrlich S. N.
Published: July 2002

An ultrahigh vacuum chamber has been developed for structural analysis of adsorbed films and single-crystal surfaces using synchrotron x-ray diffraction. It is particularly well suited for investigations of physisorbed and other weakly bound films. The chamber is small enough to transport and mount directly on a standard four-axis diffractometer and can also be used independently of the x-ray diffractometer. A low-current, pulse-counting, low-energy electron diffraction/Auger spectroscopy system with a position-sensitive detector enables in situ characterization of the film and substrate while the sample is located at the x-ray scattering position. A closed-cycle He refrigerator and electron bombardment heater provide controlled substrate temperatures from 30 to 1300 K. The chamber is also equipped with an ion sputter gun, a quadrupole mass spectrometer, and a gas handling system. Details of the design and operation of the instrument are described. To demonstrate the performance of the instrument, we present some preliminary results of a study of Xe physisorbed on the Ag(111) surface.
Dynamic light scattering with a CCD camera
Authors: Wong Apollo P. Y. , Wiltzius P.
Published: July 2002

We have successfully implemented a method to measure intensity autocorrelation functions with a CCD camera and a fast computer. We report light scattering experiments on solutions of diffusing latex spheres in glycerol and compare our results to those obtained with a conventional hardwired electronic correlator. Averaging allows significant reduction of measurement times and makes this technique suitable for the study of systems with very long time scales. Moreover, the CCD setup allows measurement of two-time correlation functions under nonequilibrium conditions where conventional correlators which rely on time-averaging fail. The new method may offer significant advantage for low-intensity applications like x-ray correlation spectroscopy.
Self-cleaning Langmuir probe
Authors: Amatucci W. E. , Koepke M. E. , Sheridan T. E. , Alport M. J. , Carroll J. J.
Published: July 2002

A contamination-free Langmuir probe of novel design is described. Surface contaminants, which lead to erroneous evaluation of plasma parameters by distortion of the probe’s current-voltage characteristic, are removed by the indirect heating of the probe tip with separate heating elements running parallel to the probe wire in multibore alumina tubing. This configuration minimizes magnetic field perturbations, while maintaining the compact profile and construction ease of an unheated probe. The design and operating characteristics of such a probe are reported. Temperatures at the probe tip, as measured by a subminiature thermocouple, can exceed 500 °C. Experiments determining the effect of probe temperature, Tprobe, on the characteristic have been performed in a Q-machine plasma (Ti≊Te≊0.2 eV). We find that for Tprobe<250 °C, the measured electron temperature is up to several times too large, indicating the presence of a contamination layer. This contamination layer is removed for Tprobe ≥300 °C, and accurate electron temperatures are recovered.
A noncontact measurement technique for the specific heat and total hemispherical emissivity of undercooled refractory materials
Authors: Rulison Aaron J. , Rhim Won-Kyu
Published: July 2002

A noncontact measurement technique for the constant pressure specific heat (cpl) and the total hemispherical emissivity (εTl) of undercooled refractory materials is presented. In purely radiative cooling, a simple formula which relates the post-recalescence isotherm duration and the undercooling level to cpl is derived. This technique also allows us to measure εTl once cpl is known. The experiments were performed using the high-temperature high-vacuum electrostatic levitator at JPL in which 2–3 mm diameter metallic samples can be levitated, melted, and radiatively cooled in vacuum. The averaged specific heats and total hemispherical emissivities of Zr and Ni over the undercooled regions agree well with the results obtained by drop calorimetry: cpl,av(Zr)=40.8±0.9 J/mol K, εTl,av(Zr)=0.28±0.01, cpl,av(Ni)=42.6±0.8 J/mol K, and εTl,av(Ni)=0.16±0.01.
Evidence for hydrogen incorporation during porous silicon formation
Authors: Allongue P. , Henry de Villeneuve C. , Pinsard L. , Bernard M. C.
Published: July 2002

The incorporation of hydrogen into Si, under different electrochemical conditions including anodization in fluoride solutions where porous silicon is formed, is studied by NRA and in situ capacitance measurements. Results suggest a large near surface concentration of H whilst simulation show that the maximum penetration depth is governed by volume diffusion of H and material removal. Diffusion coefficients are found to be dependent on electrochemical conditions and ranged between 10−13 and 10−11 cm2 s−1. The interplay of H permeation with porous silicon layer formation is discussed.
Design and performance of a 2T permanent magnet wiggler for the Stanford Synchrotron Radiation Laboratory
Authors: Stekly Z.J.J. , Gardner Craig , Baker James , Domigan Paul , Hass Mat , McDonald Carol , Wu Curtis
Published: July 2002

The Beamline 9 Wiggler was designed by Intermagnetics to produce a 16 milliradian fan of high energy x-rays into three experimental stations. The device has a 26 cm period and contains 7.5 full-strength periods. The minimum air gap is 2.1 cm. At minimum gap, a peak field of 1.9 Tesla and a half-period integrated field strength of ≥16.646 T-cm were specified by the Stanford Synchrotron Radiation Laboratory (SSRL). A combination of analytical, PANDIRA, and scale models were used to develop a novel ‘‘compact pole’’ magnetic design. This design achieved 2.04 T peak field while maintaining a minimum of 17.816 T-cm half-period integrated field strength. Magnetic performance of the device was confirmed through the use of an Intermagnetics-designed Hall Probe scanning system as well as by long and short coil measurements.
FEA analysis of diamond as IMCA’s monochromator crystal (abstract)
Authors: Chrzas John , Cimpoes Sorinel , Ivanov Ivan Neschev
Published: July 2002

A great deal of effort has been make in recent years in the field of undulator high heat load optics, and currently there are several tractable options [Rev. Sci. Instrum. 69, 2792 (1994); Nucl. Instrum. Methods A 266, 517 (1988); Nucl. Instrum. Methods A 239, 555 (1993)]. Diamond crystals offer some attractive options–water as the coolant, the use of established monochromator mechanisms, simpler monochromator design as compared to the use of liquid nitrogen or gallium. The use of diamond crystals as the optical elements in a double-crystal monochromator for the IMCA-CAT and MR-CAT ID beamlines has been studied. A first crystal mounting scheme using an indium-gallium eutectic as the heat transfer medium developed in collaboration with DND-CAT and M. Hart will be presented. A FEA analysis of the IMCA-CAT ID beamline arrangement using the APS undulator A as the radiaiton source will be presented.
APS undulator radiation—first results
Authors: Cai Z. , Dejus R. J. , Den Hartog P. , Feng Y. , Gluskin E. , Haeffner D. , Ilinski P. , Lai B. , Legnini D. , Moog E. R. , Shastri S. , Trakhtenberg E. , Vasserman I. , Yun W.
Published: July 2002

The first undulator radiation has been extracted from the Advanced Photon Source (APS). The results from the characterization of this radiation are very satisfactory. With the undulator set at a gap of 15.8 mm (K=1.61), harmonics as high as the 17th were observed using a crystal spectrometer. The angular distribution of the third-harmonic radiation was measured, and the source was imaged using a zone plate to determine the particle beam emittance. The horizontal beam emittance was found to be 6.9±1.0 nm-rad, and the vertical emittance coupling was found to be less than 3%. The absolute spectral flux was measured over a wide range of photon energies, and it agrees remarkably well with the theoretical calculations based on the measured undulator magnetic field profile and the measured beam emittance. These results indicate that both the emittance of the electron beam and the undulator magnetic field quality exceed the original specifications.
Medical imaging (invited, abstract)
Authors: Chapman Dean
Published: July 2002

There are a number of medically related imaging programs at synchrotron facilities around the world. The most advanced of these are the dual energy transvenous coronary angiography imaging programs, which have progressed to human imaging for some years. The NSLS facility will be discussed and patient images from recent sessions from the NSLS and HASYLAB will be presented. The effort at the Photon Factory and Accumulator Ring will also be briefly covered, as well as future plans for the new facilities. Emphasis will be on the new aspects of these imaging programs; this includes imaging with a peripheral venous injection of the iodine contrast agent, imaging at three photon energies, and the potential of a hospital-based compact source. Other medical programs to be discussed, are the multiple energy computed tomography (MECT) project at the NSLS and plans for a MECT program at the ESRF. Recently, experiments performed at the NSLS to image mammography phantoms using monochromatic beam have produced very promising results. This program will be discussed as well as some new results from imaging a phantom using a thin Laue crystal analyzer after the object to eliminate scatter onto the detector.
Precision manufacturing using LIGA (abstract)
Authors: Jackson Keith H. , Malek Chantal Khan , Bonivert William D. , Hruby J. M. , Hachman J. T. , Brennen Reid A. , Wiberg Dean , Hecht Michael H.
Published: July 2002

Our objective is the fabrication of small high-precision parts using LIGA, which can be used in a variety of industrial applications. LIGA is a combination of deep x-ray lithography, electroplating, and replication processes that enables the fabrication of microstructures with vertical dimensions several millimeters high, lateral dimensions in the micrometer range, and submicron tolerances. On beamline 10.3.2, at the Advanced Light Source (ALS), the Center for X-ray Optics (CXRO) has built an end station suitable for LIGA. The ALS is an excellent source of radiation for this application. The CXRO, in close collaboration with Sandia National Laboratory and the Jet Propulsion Laboratory, has developed the other essential process steps of mask making, resist development, x-ray exposure, and electroplating. This technology provides a powerful tool for mass production and miniaturization of mechanical systems into a dimensional regime not accessible by traditional manufacturing operations. We will present several applications that exploit the characteristics of the LIGA process: the fabrication of magnetic laminations for a high precision stepping motor; miniature octopole lens for advanced e-beam lithography; high-aspect-ratio x-ray collimating grids for astronomy; and microscopic tumblers for nuclear security.
Wide-bandpass ‘‘multilayer’’ monochromator for small angle scattering/diffraction studies on biological systems (abstract)
Authors: Tsuruta Hiro , Tompkins W.H. , Hodgson K.O. , Irving T. , Chen L. , Segel D.
Published: July 2002

We have utilized a ‘‘multilayer’’ monochromator (a pair of layered synthetic microstructures) in small-angle x-ray scattering/diffraction studies of biological materials. Many biological applications of the SAXS/D technique, in particular time-resolved studies, are often limited by the flux available to experiments. The wider energy bandpass of the multilayer monochromator provides a higher beam flux by a factor of 10 or more, compared with that of the Si(111) double-crystal monochromator. At the SSRL BL 4-2 SAXS/D facility, two types of multilayers have been used: Mo/C on Si substrate, fabricated at Lawrence Berkeley Laboratory [S. Brennan et al., Nucl. Instrum. Methods Phys. Res. A 347, 417 (1994)] and Mo/B4C on Si substrate, obtained from Osmic, Inc. The energy bandpass of the former multilayer is about 150 eV at 10 keV, and that of the latter is expected to be slightly wider. A pair of the latter multilayers gives 8 x 1011 photons/s in a beam size 1 x 2 mm2 (FWHM) at a photon beam energy of 9 keV and a SPEAR ring current of 85 mA. We will present excellent quality diffraction/scattering patterns from muscle fibers and protein solutions that show no significant smearing artifacts due to the wider energy bandpass.
Interferometry using undulator sources (invited, abstract)
Authors: Beguiristain R. , Goldberg K. A. , Tejnil E. , Bokor J. , Medecki H. , Attwood D. T. , Jackson K.
Published: July 2002

Optical systems for extreme ultraviolet (EUV) lithography need to use optical components with subnanometer surface figure error tolerances to achieve diffraction-limited performance [M.D. Himel, in Soft X-Ray Projection Lithography, A.M. Hawryluk and R.H. Stulen, eds. (OSA, Washington, D.C., 1993), 18, 1089, and D. Attwood et al., Appl. Opt. 32, 7022 (1993)]. Also, multilayer-coated optics require at-wavelength wavefront measurement to characterize phase effects that cannot be measured by conventional optical interferometry. Furthermore, EUV optical systems will additionally require final testing and alignment at the operational wavelength for adjustment and reduction of the cumulative optical surface errors. Therefore, at-wavelength interferometric measurement of EUV optics will be the necessary metrology tool for the successful development of optics for EUV lithography. An EUV point diffraction interferometer (PDI) has been developed at the Center for X-Ray Optics (CXRO) and has been already in operation for a year [K. Goldberg et al., in Extreme Ultra Lithography, D.T. Attwood and F. Zernike, eds. (OSA, Washington, D.C., 1994), K. Goldberg et al., Proc. SPIE 2437, to be published, and K. Goldberg et al., J. Vac. Sci. Technol. B 13, 2923 (1995)] using an undulator radiation source and coherent optics beamline at the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory. An overview of the PDI interferometer and some EUV wavefront measurements obtained with this instrument will be presented. In addition, future developments planned for EUV interferometry at CXRO towards the measurement of actual EUV lithography optics will be shown.
Characterization of thermal distortion effects on beamline optics for EUV interferometry and soft x-ray microscopy
Authors: Beguiristain R. , Underwood J. H. , Koike M. , Batson P. , Medecki H. , Rekawa S. , Jackson K. , Attwood D.
Published: July 2002

This study analyzes synchrotron radiation heat loading effects on optical components of beamline BL12.0 for EUV interferometry and soft x-ray microscopy at the Advanced Light Source (ALS). Newly developed indirect side-cooled beamline optics were considered, and the resulting surface distortion of mirrors and grating indicates that there is no significant degradation of beamline performance in spectral resolution or throughput. Also analyzed are the effects of heat loading on end-station components, such as Fresnel zone plates, transmission gratings, masks and membranes. Experimental results of heat loaded membranes are presented as well in this writing.
Status of the Advanced Photon Source at Argonne National Laboratory (invited)
Authors: Moncton David E.
Published: July 2002

The Advanced Photon Source at Argonne National Laboratory is a third-generation light source optimized for production of high-brilliance undulator radiation in the hard x-ray portion of the spectrum. A user community representing all major centers of synchrotron research, including universities, industry, and federal laboratories, will utilize these x-ray beams for investigations across a diverse range of disciplines. All technical facilities and components required for operations have been completed and installed, and are well along in the commissioning process. Major design goals and Department of Energy milestones have been met or exceeded. Project funds have been maximized to construct a number of beamline components and user facilities over and above those called for in the original project scope. Research teams preparing experimental apparatus at the Advanced Photon Source have procured strong funding support.
Innovations in the operation of storage rings (invited)
Authors: Hettel R. O.
Published: July 2002

Developments in stored beam measurement, control, and modeling methods at synchrotron radiation laboratories around the world are helping to produce brighter, more stable beams having improved temporal and spectral properties. Beam-based storage ring lattice identification and model calibration, beam dynamics monitoring and stabilizing systems, and improved operational procedures facilitated by advanced control systems are benefitting new and older facilities alike. An overview of these innovations and their impact on photon beam quality is presented.
Experience with small-gap undulators (invited)
Authors: Stefan P.M. , Krinsky S.
Published: July 2002

Small-gap undulators offer enhanced performance as synchrotron radiation sources, by providing extended tuning range and the possibility of higher photon energies via short-period, small-gap devices. Challenges associated with the operation of small-gap undulators arise from their requirement for small beam apertures and the resulting possibility of lifetime degradation, beam instabilities, and radiation hazards. To investigate these fundamental limitations, we have constructed an R&D small-gap undulator for the X13 straight section of the NSLS 2.584 GeV X-ray Ring and have tested it during studies shifts and normal user shifts during the last year. This device, the NSLS prototype small-gap undulator (PSGU), consists of a variable-aperture vacuum chamber and a 16-mm-period pure-permanent-magnet undulator, both mounted to a common elevator base stage. The design output spectrum of 2.5 keV in the fundamental (and 7.5 keV in the third harmonic) was obtained with a magnet gap of 5.6 mm and an electron beam aperture of 2.5 mm. The partial lifetime contribution for these parameters was observed to be about 40 hr. Details of the synchrotron radiation output spectrum, lifetime dependence on aperture, and bremsstrahlung radiation production will be presented.
A new double-crystal monochromator for UHV operation in the low to medium photon energy range
Authors: Mason W.P. , Emmel G.R. , Feyzi F. , Holly D.J. , Middleton F.H. , Pagac A.J.
Published: July 2002

The University of Wisconsin-Madison Physical Sciences Laboratory (PSL) has developed a new concept patented double-crystal monochromator for instruments operating in the low to medium photon energy range. Presently PSL is engaged in a collaborative project with the Pohang Light Source in South Korea to provide the internal mechanism for such a DCM; Pohang will supply the vacuum chamber and scan drive. The concept utilizes a straight arm linear rotating link called the ‘‘broomstick’’ that is a cotangent generator. Coupled to the broomstick is a pair of unique half angle mechanisms that rotate the crystals at half the angle of the broomstick while maintaining crystal parallelism during the scan rotation. An external linear drive to one crystal through a bellows assembly provides the only required input for operation of the monochromator other than crystal angular adjustments by manual or piezoelectric means. The instrument is capable of operating at Bragg angles from 8° to 80°. This results in an energy range of 2 keV to 14.2 keV for Si(111) crystals. The instrument is also capable of UHV operation in the 1.0E−10 Torr range.
A new microwave cavity resonator for determining molecular orientation and dielectric anisotropy of sheet materials
Authors: Osaki Shigeyoshi
Published: July 2002

A new type of microwave instrument is developed for quick determination of the molecular orientation and dielectric anisotropy in sheet materials. Its cavity resonator differs from the conventional one in that the waveguide is separated by a narrow gap. Thus, it consists of a pair of rectangular waveguides, each partitioned by an iris plate. A given sheet is inserted into the gap, and can be rotated around the axis normal to its plane. The iris diameter and gap width are determined so as to meet the requirement that the transmitted microwave power and the Q value may not drop markedly after insertion of thick films into the gap. Polarized microwaves are irradiated perpendicularly to the sheet, and the transmitted wave intensity is measured at every 1° of rotation angle as the sheet is rotated at a speed of 6.0 s per turn. This operation quickly gives information related to the molecular orientation in the given sample. Dielectric measurements can be made at any rotation angles, allowing the angular dependence of the real and imaginary parts of the complex dielectric constant and, thus, the dielectric anisotropy of the sheet to be determined in a few minutes.
Measurement of ion charge state distributions inside electron cyclotron resonance neon and chlorine plasmas by x-ray spectroscopy
Authors: Grübling P. , Küchler D. , Ullrich A. , Werner T. , Zschornack G.
Published: July 2002

Energy dispersive x-ray spectroscopy of Kα transitions of neon and chlorine ions inside an electron cyclotron resonance (ECR) plasma is used to analyze the ion charge state distribution (CSD) inside the plasma. Basing on a computer code describing time dependent and stationary solutions of the balance equations for the CSD in ECR plasmas (considering single and multiple ionization and charge exchange processes, radiative recombination, vacancy cascades, and electron shake-off) and considering atomic properties (fluorescence yields, transition rates, x-ray energy shifts, x-ray production cross sections) of ions with different charge states, an approximation of simulated x-ray spectra to measured ones is possible. Thus the result we get is the corresponding CSD and information about the electron energy distribution function in the low energy region in the plasma.
Characterization of a cryogenically cooled high-pressure gas jet for laser/cluster interaction experiments
Authors: Smith R. A. , Ditmire T. , Tisch J. W. G.
Published: July 2002

We have developed and carried out detailed characterization of a cryogenically cooled (34–300 K), high-pressure (55 kTorr) solenoid driven pulsed valve that has been used to produce dense jets of atomic clusters for high intensity laser interaction studies. Measurements including Rayleigh scattering and short pulse interferometry show that clusters of controlled size, from a few to >104 atoms/cluster can be produced from a broad range of light and heavy gases, at average atomic densities up to 4×1019 atoms/cc. Continuous temperature and pressure control of the valve allows us to vary mean cluster size while keeping the average atomic density constant, and we find that many aspects of the valves behavior are consistent with ideal gas laws. However, we also show that effects including the build up of flow on milliseconds time scales, the cooling of gas flowing into the valve, and condensation of gas inside the valve body at temperatures well above the liquefaction point need to be carefully characterized in order to decouple the operation of the jet from the laser interaction physics.
Cavity ring down spectroscopy on radicals in a supersonic slit nozzle discharge
Authors: Motylewski Tomasz , Linnartz Harold
Published: July 2002

A sensitive and generally applicable technique for direct absorption spectroscopy on electronic transitions of transient species in the gas phase is presented. The method is based on cavity ring down spectroscopy in a pulsed slit nozzle, incorporating a discharge in a high pressure supersonic expansion. The performance is demonstrated with spectra of the 000 origin band of the Π2←X2Π electronic transition of the isoelectronic linear carbon chain radicals C6H and C6H2+. Rotationally resolved and rotationally cold spectra (Trot<15 K) have been obtained. The sensitivity of the technique is demonstrated for anions with a detection limit as low as 107 C2− molecules cm−3 for rovibrational transitions of the B2Σu+←X2Σg+ system.
A passive two-band sensor of sunlight-excited plant fluorescence
Authors: Kebabian Paul L. , Theisen Arnold F. , Kallelis Spiros , Freedman Andrew
Published: July 2002

We have designed and built a passive remote sensor of sunlight-excited chlorophyll fluorescence (U.S. Patent No. 5,567,947, Oct. 22, 1996) which provides for the real-time, in situ sensing of photosynthetic activity in plants. This sensor, which operates as a Fraunhofer line discriminator, detects light at the cores of the lines comprising the atmospheric oxygen A and B bands, centered at 762 and 688 nm, respectively. These bands also correspond to wavelengths in the far-red and red chlorophyll fluorescence bands. The sensor is based on an induced fluorescence approach; as light collected from fluorescing plants is passed through a low-pressure cell containing oxygen, the oxygen absorbs the energy and subsequently reemits photons which are then detected by a photomultiplier tube. Since the oxygen in the cell absorbs light at the same wavelengths that have been strongly absorbed by the oxygen in the atmosphere, the response to incident sunlight is minimal. This mode of measurement is limited to target plants sufficiently close in range that the plants’ fluorescence is not itself appreciably absorbed by atmospheric oxygen (∼200 m). In vivo measurements of fluorescence in the 760 and 690 nm bands of vegetation in full sunlight are also presented. Measurements of plant fluorescence at the single-plant canopy level were obtained from greenhouse-grown bean plants subjected to a range of nitrogen treatments. The ratio of the fluorescence obtained from the two measurement bands showed statistically significant variation with respect to nitrogen treatments.
Laser-induced rotation of a levitated sample in vacuum
Authors: Rhim Won-Kyu , Paradis Paul-François
Published: July 2002

A method of systematically controlling the rotational state of a sample levitated in a high vacuum using the photon pressure is described. A zirconium sphere was levitated in the high-temperature electrostatic levitator and it was rotated by irradiating it with a narrow beam of a high-power laser on a spot off the center of mass. While the laser beam heated the sample, it also rotated the sample with a torque that was proportional both to the laser power and the length of the torque arm. A simple theoretical basis was given and its validity was demonstrated using a solid zirconium sphere at ∼2000 K. This method will be useful to systematically control the rotational state of a levitated sample for the containerless materials processing at high temperature.