bluuebunny/crossref_metadata_2025 huggingface dataset:
Morphology and Polarity of Twinned Crystals in II-VI Compounds
Authors: Iwanaga Hiroshi , Yoshie Toshimasa , Yamaguchi Taeko , Shibata Noboru
Published: November 2005

ZnO twinned crystals with the composition plane (101̄1) or (112̄2) were grown by oxidizing ZnSe in the vapor phase. The twinned crystals consisted of two plate crystals grown in the +c and -c directions. CdS and CdSe twinned crystals with the composition plane (101̄1) were also grown by the sublimation method. Both of these consisted of branch crystals growing around an original (central) c-needle which grew in the -c direction. These branch crystals made an angle of 56° with the original c-needle. They grew in the +c direction in CdS and in the -c direction in CdSe.
Analytical Calculation of Energy Spectra of keV Light Particles Reflected from Solid Surfaces
Authors: Morita Kenji
Published: November 2005

The energy spectra of keV light particles reflected from solid surface have been calculated within the single collision approximation, taking account of the angular and lateral deviations of the indident beam caused by multiple small-angle collisions. The particle and energy reflection coefficients (R
N and R
E) have also been calculated as a function of the reduced energy (ε
0) in Thomas-Fermi units. It is shown that for various targets, the shape of the energy spectra at given incident and ejection angles depends only on ε
0 and that the values of R
N and R
E are scaled by a universal function of ε
0. Typical values of the calculated particle reflection coefficients for Au and C, together with the energy spectra for Au at normal indidence and for Fe at oblique incidence are shown to agree well with the experimental data on keV H+ obtained by the Garching group.
Improved-Brooks Mobility Formula for Disorder Scattering in Semiconductor Alloys
Authors: Nishinaga Tatau , Hiramatsu Kazumasa
Published: November 2005

The Green function method is used to study disorder scattering in compound semiconductor alloys, taking into account many-body scattering. The present calculation and the Brooks disorder scattering mobility are compared. For typical semiconductor alloys, the discrepancy is as much as ∼20%, but the error is much smaller for alloys with small band edge difference and effective mass. By using an approximate Green function, an improved Brooks formula is derived in the form of the original Brooks formula multiplied by a correction factor.
Optogalvanic Effect Study of Vibrational Relaxation in CO2Laser Process
Authors: Shimizu Fumiko O. , Sasaki Koji , Ueda Kenichi
Published: November 2005

The amplitude and phase retardation of the optogalvanic signal in a CO2–N2–He laser plasma irradiated by a 10.6 µm CO2laser were measured under various experimental conditions. It is shown that the mechanism of the optogalvanic effect is related to the vibrational relaxation processes of the laser levels. The collisional rate constant relevant to the upper laser level (001) is determined as (2.6±0.5)×102/Torr·s at 300 K. Good agreement is obtained between the present value and the value previously obtained by the infrared pulse gain method. A new model for the optogalvanic effect is proposed, taking three relaxation processes into consideration. The dependence of the optogalvanic effect on the pressure and modulation frequency is calculated using this model and a reasonable set of parameters, and shows good agreement with the observations.
Local Dependence of Rise Time of Spectral Line Intensities in Ne Glow Discharge Tube
Authors: Yamashita Masafumi
Published: November 2005

The radial dependence of line intensities in an impulsive Ne glow discharge was investigated with particular attention being paid to the initial temporal changes of emissive line intensities. Two kinds of discharge tube, a cylindrical hollow cathode (C.H.C.) tube and a plane disk cathode (P.D.C.) tube, were used. The empirical formulae for the radial dependence of the temporal line intensities before reaching the stationary state are presented, with the experimental confirmation that the well-known simple Bessel function type formula is obtained in the C.H.C. at low pressure in the stationary state.
Runaway Electrons in the Small Shell-Less Tokamak Device NOVA-I
Authors: Nishimura Eiichi
Published: November 2005

The mechanisms of the production and confinement of runaway electrons in the tokamak device NOVA-I were studied by experimentally measuring the energies of these electrons examining how their behavior depended on the discharge parameters. Numerical calculations were also made on their drift orbits. From a comparison of the experimental and numerical analyses, it is concluded that: (1) neutral particles obstruct the production of runaway electrons during the breakdown phase of the discharge, while the densities of electrons having energies of the order of 10 eV build up; (2) electrons then begin to run away in the hot central region of the plasma, since the density of neutral particles decreases with ionization; (3) the orbits of the runaway electrons shift outward while spreading radially as the energy of the runaway electrons increases with time, until the orbits intersect the outer limiter or the torus wall.
Preservation of Point Defect Distribution in FZ Silicon
Authors: Mizuo Shoichi , Higuchi Hisayuki
Published: November 2005

Evidences for the preservation of point defect distribution in FZ Si crystals have been observed by two experimental methods. One is divided selective oxidation and the other is divided backside selective oxidation with Si3N4 as the oxidation resistant films. In both experiments, the selective oxidation is divided into several oxidation steps, and the effects of oxidation division on the range of oxidation effects on impurity diffusion is investigated.
The results show that, both laterally and vertically from the oxidizing Si–SiO2 interface, the effect of oxidation on impurity diffusion is determined only by total oxidation time. This suggests that point defect distribution is preserved after heat treatment.
Effect of Gas on the Electret Charge Reduction by Radiation
Authors: Ikeya Motoji
Published: November 2005

The radiation-induced reduction of the surface charge on polymer foil thermoelectrets has been studied in relation to the effect of the gas surrounding the electret. The reduction of the charge due to gas ion collection depends strongly on the gas in the chamber. The charge reduction in a parallel-plate electret dosimeter is treated theoretically following the ionization chamber theory for the electret-induced electric field strength of the ionization chamber region (ICR) and the gas ion recombination region (RR). The exponential reduction of the charge by radiation in an intense electret of fluoride polymers is also described, using the gas ion multiplication model. The electric field induced by the electret is considered to have entered the proportional counter region (PCR).
Ion Beam Etching of InP. I. Ar Ion Beam Etching and Fabrication of Grating for Integrated Optics
Authors: Yuba Yoshihiko , Gamo Kenji , Toba Hiroshi , He Xi Guan , Namba Susumu
Published: November 2005

The Ar ion beam etching (IBE) of InP has been studied in orded to clarify its applicability as a microfabrication technique for devices with submicron geometry such as integrated optics devices. The IBE rate has been determined as a function of ion energy, current density and angle of beam incidence. The crystalline quality of the etched surface has been investigated by electron beam diffraction, Rutherford backscattering and photoluminescence measurements. The etched surface has a polycrystalline phase and recovers to a single crystal after annealing at 500 C. Grating structures with a period of around 2600 A have been fabricated on an InP surface by the Ar-IBE combined with a holographic-photoresist-exposure technique.
Ion Beam Etching of InP. II. Reactive Etching with Halogen-Based Source Gases
Authors: Yuba Yoshihiko , Gamo Kenji , He Xi Guan , Zhang Yu Shu , Namba Susumu
Published: November 2005

The reactive-ion beam etching (R-IBE) characteristics of InP with Cl2, CCl2F2 and CHF3 have been studied. Some R-IBE characteristics of GaAs have also been studied. The etching rate for each gas has been determined as a function of ion energy, current density and angle of indidence. The highest etching rate, around 2000 Å/min, is obtained in Cl2-IBE, while the two other source gases yield an etching rate lower than that of Ar-IBE. In the case of CCl2F2-IBE, the addition of Ar is found to enhance the etching considerably. These IBE techniques are used to fabricate a grating structure with a period around 2500 A.
High-Remaining Dry-Developed Resist Patterns of Steep Profile
Authors: Tsuda Minoru , Yokota Akira , Kashiwagi Ken-ichi , Yabuta Mitsuo , Oikawa Setsuko , Kanai Wataru , Nakane Hisashi
Published: November 2005

A dry developable resist composition which gives a steep profile pattern and high-remaining resist thickness (ca. 90%) is described. The composition comprises poly (methyl isopropenyl ketone), PMIPK, and 4,4'-diazidodiphenyl sulfone. The resist patterns were developed by a well-controlled pure oxygen plasma. The exposure time was 3.6–6.0 sec for a deep UV contact printer and the development time required was 80 sec. A resolution of 0.5 µm of the steep-profiled lines was easily obtained. The photochemical reaction mechanism and some properties of the dry-developed resist pattern are discussed.
Ferroelectric Relaxation in a 65/35 mol% Copolymer of Vinylidene Fluoride and Trifluoroethylene
Authors: Ohuchi Masayuki , Chiba Akio , Date Munehiro , Furukawa Takeo
Published: November 2005

Dielectric relaxations associated with the ferroelectric transition have been investigated in a copolymer containing 65 mol% vinylidene fluoride and 35 mol% trifluoroethylene. The transition shows thermal hysteresis, taking place at 100°C upon heating and at 70°C upon cooling. Near the transition point, there is a peak in the dielectric relaxation strength Δ
ε and a shoulder in the relaxation time τ. These anomalies and hysteresis are removed by taking the ratio of τ to Δ
ε, which corresponds to the kinetic coefficient. From its Arrhenius-type temperature dependence, the activation energy is estimated to be 16 kcal/mol both below and above the transition point. The molecular motions responsible for the ferroelectric relaxation in this copolymer are thought to occur intramolecularly by a trans-gauche transformation in the crystalline regions.
Magnetic Relaxation in Amorphous (Fe1-xNix)77Si10B13 Alloys
Authors: Miyazaki Terunobu , Hisatake Keizo , Takahashi Minoru
Published: November 2005

Disaccommodation (D
A) and the magnetic annealing effect in amorphous (Fe1-x
Ni
x
)77Si10B13, 0≦x≦0.8, alloys have been studied as a means of investigating the mechanism of structural relaxation in amorphous solids. The relaxation process is divided into two stages. The first stage, bolow about 200°C, is caused by the movement of metalloid atoms and the second, above 200°C, by diffusion of the constituent atoms. It is shown that the origin of D
A is the same as that of induced magnetic anisotropy.
Curved Crystal Spectrometer with Position-Sensitive Solid-State Detector for Plasma Diagnostics
Authors: Morita Shigeru , Kadota Kiyoshi , Fujita Junji
Published: November 2005

The characteristics of a Johann-type crystal spectrometer with a photodiode array (PDA) are described. The crystal used is LiF(200) with a bending radius of 100 cm, and the sensitivity of the PDA is measured for X-rays of 4 to 17 key. The collection efficiency η of charges created in the PDA is determined as a function of the X-ray energyE(keV): η=-0.026E+0.68. An asymmetrical spectral profile is observed when a monochromatic X-ray beam is incident on the PDA with an angle larger than 40°. The sensitivity of the spectrometer is also calibrated against a conventional X-ray tube. The PDA is used for the observation of X-ray lines from a high-temperature plasma in a vacuum spark. The resultant FeKα spectrum shows a spread over several channels due to blooming, when compared with that recorded on Kodak no-screen X-ray film.
Behavior of Thin Arc Plasma in a Self-Crowbar Air Gap
Authors: Ikuta Kazunari , Ueno Isao
Published: November 2005

The measurement of the drift speed of an arc plasma in a self-crowbar air gap is reported, the speed being measured during the growth phase of the current in the device. The drift speed is concluded to be constant with time during this phase, although the force from the magnetic pressure is not constant during current start-up. This makes possible the design of a practical self-crowbar air gap switch. The possibility of designing a self-crowbar rotary air gap switch (SCRAGS), in which the rotary motion of the arc would dramatically lower the heat load on the electrode material, is also pointed out.
SAXS and AE Studies on the Origin of Softening in Poly (methyl Methacrylate) under Uniaxial Tensile Stress
Authors: Shichijyo Shiro , Shirouzu Shigenori , Taki Seiji , Matsushige Kazumi , Takemura Tetuo
Published: November 2005

Acoustoelastic properties of poly (methyl methacrylate) under uniaxial tensile stress were investigated by the ultrasonic measurement at 5 MHz. The softening phenomenon in sound velocity along the stress direction and its anisotropic behavior were confirmed in MHz region, as already observed by Brillouin scattering in GHz region. It was clarified that the origin of this phenomenon was attributed to the formation of embryonic states for submicrocracks, based on the results of small angle X-ray scattering (SAXS) studies on the developments of size and concentration of submicrocracks under various strains. Furthermore, the events of structural conversions from embryos to submicrocracks were detected by the acoustic emission (AE) measurements.
Studies on Trapping of Laser-Produced Plasma by SL-1 Surmac
Authors: Kogoshi Sumio , Asano Hiroshi , Kisaka Masashi , Sekiguchi Tadashi
Published: November 2005

A beryllium plasma was produced in a small “Surmac” container (named SL-1 Surmac), by utilizing a neodymium-glass laser of ∼5J and ∼35ns (FWHM). The dependence of the initial particle loss due to the plasma effusion across the container field on the magnetic field strength of the Surmac was observed, and it was found that the effusion decreases drastically above a certain threshold value of the magnetic field. At stronger field, the total amount of plasma particles trapped by the container attains its maximum about 20 µs after the laser shot and it is 25 to 37 percent of that initially produced by the laser pulse. The plasma parameters obtained are as follows: average electron density 3×1012cm-3, electron temperature ∼10 eV and maximum plasma-beta value at outer “bridge” position, three percent. The plasma particle confinement time is about 44 µs, it exhibits a very weak dependence on the magnetic field and agrees approximately with that calculated from the particle loss to the mechanical supports for the internal current conductors and the beryllium target alone.
Spin Polarization due to Low-Energy Electron Diffraction at the W(001) Surface
Authors: Koike Kazuyuki , Hayakawa Kazunobu
Published: November 2005

The spin polarization in low-energy electron diffraction (LEED) from a clean W(001) surface, as well as from a surface exposed to residual gas, has been measured with a newly-constructed compact Mott detector. At a particular electron energy and incident angle, exposure of a clean surface to 0.5 Langmuir of residual gas causes a significant polarization change, from -45% to +31%. This characteristic is not inconsistent with results reported by other workers under different diffraction conditions.
Pattern Fidelity in Submicron Lithography with a Rectangular Electron Beam
Authors: Okubo Tsuneo , Takamoto Kiichi
Published: November 2005

The energy density profiles deposited in a PMMA resist film by a 0.5 µm square electron beam are calculated by Monte Carlo simulation. The influence of a combination of beam accelerating voltages and beam edge widths on the pattern fidelity is studied by examining some characteristic parameters. Simulation shows that one of these parameters, the energy efficiency, has a tendency to saturate above 50 kV, and that larger beam edge widths are allowable for higher voltages in obtaining the desired values for the characteristic parameters, which are exemplified by a normalized energy edge slope and the roundness of the square pattern. A combination of voltages of 30–50 kV and a beam edge width of <0.2 µm is desirable in 0.5 µm lithography. High-fidelity 0.5 µm patterns are obtained experimentally with an electron beam system employing writing strategies based on this simulation.
Influence of Plasma Expansion on a Spectral Line Decaying in an Ionizing Plasma in a Theta Pinch
Authors: Ohgo Tadashi , Kawasaki Ken , Oda Toshiatsu
Published: November 2005

The particle end-loss process and its influence on the intensity of the HeII 468.6 nm line are investigated in a small linear theta-pinch plasma using spectroscopic techniques. In side-on measurement at the center of the plasma column, the HeII line intensity decreases with a much larger decay rate than in end-on measurement. The side-on decay rate is due to both the ionization and the particle-end-loss processes, while the end-on decay rate is mainly due to the ionization process. The difference between the two rates is investigated by solving rate equations involving both ionization and plasma expansion. Good agreement is obtained between the experimental and theoretical results. A simple method, using both the side-on and the end-on measurements is offered for estimating the particle-end-loss rate due to the plasma expansion.
Chemical Shifts of Photoelectron and Auger Lines in Ag- or Cu-Doped Amorphous GeSe2 and As2Se3
Authors: Ueno Tokihiro
Published: November 2005

Chemical shifts of the Ag 3d5/2,3/2, Cu 2p3/2,1/2, Ge 3d, 3p3/2,1/2, As 3d, 3p3/2,1/2, and Se 3d, 3p3/2,1/2, photoelectron lines, and the AgM4,5N45N45, GeL3M45M45 and CuL3M45M45 Auger lines are measured for Ag and Cu films, and amorphous films of Ge, As, Se, GeSe2, As2Se3, Ag-doped GeSe2, Ag-doped As2Se3 and Cu-doped As2Se3. The chemical shifts of Ge, Ag and Cu photoelectron lines are corrected for by an extra-atomic relaxation energy obtained from the chemical shifts of Ge, Ag and Cu Auger lines. These results are explained for in view of the electronegativity scales. The chemical shifts in Ag-doped GeSe2 are treated in accordance with the valence shell potential model; Ag–Se and Ge–Se bonds are attributed to covalent bonds rather than ionic bonds in terms of the amounts of ionic character and the electronegativity differences.
Measurements of Fast Time Evolutions of Plasma Potential Using Emissive Probe
Authors: Fujita Hiroharu , Yagura Shinya
Published: November 2005

We present a new method of measuring the floating potential of an emissive probe when the floating potential is very close to the plasma potential. The probe potential at which the probe current becomes zero in the current-voltage curve of the probe is automatically biased by a new probe circuit connected to a bipolar voltage source. This method enables direct measurement of rapid changes in the floating potential with a time resolution of ≃1 µs, giving a continuous data trace. The method was verified experimentally using a DP machine.
Heteroepitaxial Growth and Superstructure of Ge on Si(111)–7×7 and (100)–2×1 Surfaces
Authors: Shoji Katsuyuki , Hyodo Masahito , Ueba Hiromu , Tatsuyama Chiei
Published: November 2005

The initial stage of the heteroepitaxy, and the superstructure of Ge on Si surfaces, have been investigated by LEED and AES. Germanium was evaporated on to a clean Si(111–7×7 surface and also on to an Si(100)–2×1 surface. The layer-by-layer growth of Ge films on the Si surfaces was confirmed from the decrease in intensity of the Si(LVV)-AES signal with increase in Ge coverage. It was found that the (7×7) superstructure of the Si (111) surface is replaced by a (5×5) superstructure at about 2 monolayers coverage of Ge. The phase diagram of the superstructure of Ge on the Si(111) system was constructed for Ge coverage in monolayers evaporated at room temperature, versus annealing temperature. A similar study was also extended to Ge on an Si(100)–2×1 surface, where the original LEED pattern is not strongly distrubed at about 1–2 monolayers of Ge.
Statistical Properties of the Dynamic Polychromatic Laser Speckle
Authors: Iwai Toshiaki , Takai Nobukatsu , Asakura Toshimitsu
Published: November 2005

This paper investigates theoretically the normalized autocorrelation function of the time-varying polychromatic laser speckle intensity fluctuation produced in the Fraunhofer diffraction field by the in-plane movement of a diffuse object. The variation of the correlation time in the radial direction indicates the spatial non-stationarity of an elongated speckle pattern while that in the angular direction indicates the three different spatial structures, randomly distributed, fibrous radial and radially separated, of elongated speckles in the angular direction. The theoretical results obtained are confirmed by experiments.
A Waveform Reporduction Study of Time Domani Reflectomatry. III. Inversion of Waveforms Reflected from a Diffuse Interface
Authors: Hayashi Shigeo , Aihara Ariyuki
Published: November 2005

An approximate inversion procedure is presented for deriving the concentration distribution from TDR waveforms refldected from a diffuse interface between two miscible layers. The procedure neglects dielectric dispersion, and calculates numerically the Fourier transform of the so-called tangent function t
BB, which can be obtained approximately from the reflection coefficient. The procedure is exact when the interface is clear cut. A tetrahydrofuran/water system was treated successfully by this inversion procedure.
High-Speed Frequency Stabilization of AlGaAs Semiconductor Laser
Authors: Tsuchida Hidemi , Tako Toshiharu
Published: November 2005

The frequency of an AlGaAs semiconductor laser has been stabilized by using a wide-band servo-system (DC-500 kHz) for injection current control. A Fabry-Perot interferometer was used as the frequency reference. The dependence of the resulting frequency stability on the parameters of the servo-system was investigated. The power spectral density S
y of the frequency fluctuations was reduced by two orders of magnitude for 0<f<200 kHz.
Spectral Measurements of NH3 and H2O for Pollutant Gas Monitoring by 1.5 µm InGaAsP/InP Lasers
Authors: Ohtsu Motoichi , Kotani Hiroki , Tagawa Haruo
Published: November 2005

The absorption spectral lines of the combination tones of the vibration-rotation transitions in NH3 and H2O were measured with 1.5 µm InGaAsP/InP lasers for the purpose of pollutant gas monitoring. The numbers of observed NH3 and H2O lines were 21 and 1, respectively. The wavelengths of these lines were measured within the inaccuracy of 1.6 pm by a precise wavemeter. For these measurements, the laser wavelength was stabilized to NH3 and H2O lines. The resultant stabilities were 3.0×10-10·τ-1/2 and 1.1×10-9, respectively, where τ represents the integration time. The sensitivity of NH3 gas monitoring was measured as being 2.3×10-3 Torr · m. Furthermore, spectral measurements obtained by using an optical fiber are also presented.
Temporal Behaviors of Hα Fluorescence Induced by High-Intensity Dye-Laser in Plasmas
Authors: Usui Tatehito , Furukane Utaro , Oda Toshiatsu
Published: November 2005

The time-dependent collisional-radiative model including the effect of resonant absorption of the Hα line is applied to a hydrogen plasma in order to investigated the temporal behavior of the Hα fluorescence, which is used to determine the population density of the lower level. Four typical temporal behaviors of the fluorescence in plasmas are discussed. One of them has been found to useful for accurate determination of the population density. An experiment has also been made in a pulsed discharge plasma to demonstrate that a useful type of fluorescence can be achieved in a laboratory plasma.
Deep-Level Transient Spectroscopy of Plastically-Bent Epitaxial GaAs
Authors: Kadota Yoshiaki , Chino Ken-ichi
Published: November 2005

Trap levels in plastically-bent vapor-phase epitaxial (VPE) and liquid-phase epitaxial (LPE) GaAs n-layers were investigated by deep-level transient spectroscopy (DLTS). Two hole traps, Level A(Ev+0.38 eV) and Level B(Ev+0.68 eV), and one electron trap, EL2(Ec-0.82 eV), were found after deformation, as well as hole traps due to Cu and Fe contaimnation. No trap levels attributable to the dislocations in GaAs were found. The total amount of additional trap concentrations detected by DLTS measurements fell fairly far short of the reduction in the free carrier concentration, owing to deformation. These findings suggest that dislocation-associated traps in GaAs in themselves do not show a peak in DLTS spectra. This is tentatively discussed in connection with recent reports on the degradation of light-emitting devices.
Plasma Anodic Oxidation of InP
Authors: Fuyuki Takashi , Moriuchi Sohta , Matsunami Hiroyuki
Published: November 2005

Plasma anodic oxidation was used to obtain thick insulator films on InP, and highly-resistive gate insulator films with low interface state density were obtained by one sequential plasma process. The film formation mechanisms were revealed by structural analysis using AES on the grown film. A native oxide of InP grows in the first stage, and sputtered aluminum from the inner discharge electrodes then deposits on the native oxide, taking the form of aluminum oxide. The effects of the sample bias on the rate of growth of the film are discussed. The electrical properties of MIS diodes using the plasma anodic oxide show that the interface state density around the Fermi level is 2.5∼5×1012 cm-2eV-1, and the resistivity and the breakdown voltage are 1×1011 Ωcm and 1.5×106 V/cm, respectively.
Mass Spectrometry Ion Sampling on the Positive Column DC Discharge Plasmas
Authors: El-Kelish Salah , Hattori Shuzo
Published: November 2005

The quadrupole mass filter (QMF) calibration constant of ion sampling from the positive column of a dc discharge plasma was studied as a function of various experimental parameters such as the gas pressure, the diameter of the sampling orifice, and the nature of the gas discharge. The most important factor included in the calibration constant, the sampled ion beam attenuation from the orifice to the mass filter, is explained very satisfactorily by the Coburn-Kay model. Some experimental data are reported on the ion sampling calibration constant of neon discharges at pressures up to 8 Torr and a discharge current of between 20 mA and 80 mA. Measurements in argon and neon discharges illustrate that the transition from the Knudsen region to the near-Knudsen region is nearly independent of the type of gas.
Multipurpose Beam Pulsing System for the 12UD Pelletron Tandem Accelerator at the University of Tsukuba
Authors: Furuno Kohei , Fukuchi Yasuhiko , Kimura Takashige , Maeoka Hidenobu , Ishii Satoshi , Aoki Takayoshi
Published: November 2005

A beam pulsing system has been developed for a 12 MV tandem accelerator. The system consists of a pre-acceleration chopper, a klystron buncher and a post-acceleration chopper. The pre-acceleration chopper comprises a slow chopper and a fast travelling-wave chopper. Pulsed beams with widths in the range from 10 µs to ∼2 s are obtained with the slow chopper, and the repetition periods can be varied from 70 µs to 4 s. The fast chopper produces ion bursts having widths between 0.05 and 0.8 µs with a duty factor of ∼10%. The buncher is operated with the two choppers to obtain beam pulses as narrow as a few nanoseconds. Time-of-flight measurements yielded pulse widths 2–4 ns (FWHM) wide for ions in the mass range 1≦A≦28. The ratio of the dark to peak ion current was usually of the order of 10-4.
A 300-MeV Proton Beam Line with Energy Degrader for Medical Science
Authors: Kurihara Daiki , Suwa Shigeki , Tachikawa Akira , Takada Yoshihisa , Takikawa Koji
Published: November 2005

The design of a proton beam line for medical science is presented. A proton beam of energy ranging from 150 to 300 MeV is obtained by decelerating the 500-MeV KEK booster synchrotron beam in a carbon energy degrader. Problems associated with the use of the energy degrader in the beam line are discussed in detail. The available proton intensity at 250 MeV is estimated to be 2×109 protons per pulse with a repetition rate of 20 Hz. The beam line provides an achromatic, horizontal beam and a vertical beam. The former is suitable for proton diagnosis, and the availability of both the horizontal and the vertical beam increases the usefulness of proton radiotherapy.
Determination of the Optimum Electrode Shape of Electrostatic Einzel Lenses
Authors: Shimizu Keizo
Published: November 2005

A practical method of determining the optimum electrode shape of einzel lenses is discussed for ion microprobe applications: both the spherical and chromatic aberrations contribute, and the focal length is relatively long. A new variable D
* is introduced to express the relative aberration effect at the optimum lens design, and the values of D
* for the various electrode shapes are compared. The method is applied to typical electrode shapes, and the superiority of an asymmetric electrode shape with respect to the center electrode is shown.
Effect of Ambient Gas on Undoped LEC GaAs Crystal
Authors: Emori Haruo , Matsumura Takao , Kikuta Toshio , Fukuda Tsuguo
Published: November 2005

Undoped GaAs crystals were grown by the LEC technique from quartz crucibles in N2, He, Ar or Kr ambient gases. The influence of the ambient gases on the electrical properties and dislocation densities of the crystals was examined, and it was found that even when a quartz crucible was used, undoped GaAs crystals grown in N2 ambient became semi-insulating, while crystals grown in rare gases were n-type conductive. This effect of N2 was studied using secondary-ion mass spectrometry bulk analysis and low-temperature photoluminescence measurements. When the effect of the ambient gas on the Etch Pit Density (EPD) was investigated, dislocation densities were found to decrease in the order Kr, Ar, N2 and He, as expected from their heat transfer efficiencies.
Effects of Rare Earth Impurities on Photochromic Characteristics of Rare Earth Orthoniobates
Authors: Suemune Yasutaka
Published: November 2005

Some rare earth orthoniobates, RNbO4, have been found to exhibit photochromic properties ascribed to the formation of color centers. Compounds with rare earths, R, of gadolinium and ytterbium, have been shown to have a particularly long duration of visible coloration after ultraviolet (UV) irradiation at room temperature. Partial substitution of praseodymium or terbium as the rare earths enhances these UV coloration characteristics. Substitution of about 0.8% of terbium is remarkably effective in accelerating the thermal bleaching, increasing the bleaching rate by about one order of magnitude.
Design and Computer Simulation of Magnetic Bubble Domain Current-Access Major/Minor Loop Organization
Authors: Hayashi Nobuo , Itoh Akiyoshi , Takahashi Yoshiro , Tsukizaki Yoshiyuki , Ishii Eitaro , Kawanishi Kenji
Published: November 2005

A major/minor loop organization has been designed by using dual-conductor sheet devices. The design was carried out by consulting the drive-field distribution obtained on scaled-up models of the conductor sheets and the results of computer simulation. A device configuration has been obtained which has a fairly good operating margin for all of the necessary operations, including propagations along the minor loop and major line, minor-loop cornering, and transfer-in/out operations. This paper describes the method of drive-field measurement, the process of device improvement, an outline of the simulation method and the results of performance evaluation by computer simulation.
Silica Glass Optical Waveguide by Liquid-Phase Doping Process
Authors: Tomaru Satoru , Kawachi Masao
Published: November 2005

A new method of fabricating high-silica channel optical waveguides using porous silica glass as the starting material is demonstrated. To form the optical guide region, liquid-phase metal alcohoxide is selectively added to the porous glass, followed by consolidation of the porous glass into a transparent glass. Photopolymer, with which the porous glass is soaked and patterned, plays an essential role in the selective doping with metal alcohoxide. The propagation loss of the multi-mode wave guides fabricated by this method was about 2 dB/cm. This simple method with find applications in making various optical circuits.
Dependence of Gain on Dynode Spacing in a Parallel-Plate Electron Multiplier
Authors: Konno Tadashi , Kanayama Michio , Kiyono Setsuo
Published: November 2005

The dependence of the gain of a parallel-plate electron multiplier on the dynode spacing is obtained theoretically and examined experimentally. For a certain voltage applied to the dynodes, there is a single spacing at which maximum gain occurs. On increasing the applied voltage, this optimum spacing decreases in value and the maximum gain increases exponentially. The experimental results agree well with calculated values except at higher voltages, where gain saturation occurs.
Diffusion of Cd and Zn into InP and InGaAsP (Eg=0.95-1.35 eV)
Authors: Matsumoto Yoshishige
Published: November 2005

The diffusion of Cd and Zn into InP was investigated at temperatures ranging from 566°C to 715°C. Cd diffusion using a combination source composed of Cd3P2 and InP powder allows us to establish a shallow diffusion depth (Xj) of less than a few microns and to form a highly planar p-n junction without surface deterioration. On the other hand, Zn diffusion using a combination source consisting of Zn3P2 (or ZnP2)+InP powder proceeded rapidly and resulted in irregular diffusion fronts. When selective diffusion of Cd into InP was carried out using a PSG film mask, slip dislocations were found to be generated along the mask edge if the amount of InP powder in the diffusion ampoule was not sufficient (≤100 mg). Cd diffusion into InGaAsP (E
g=0.95–1.35 eV) lattice matched to InP was also carried out, and it was found that the diffusion depth decreases monotonically with decreasing band gap energy.
Structure of Liquid Surface and Mechanics of Surface Tension
Authors: Takahashi Ryoji
Published: November 2005

The structure of the surface of a liquid is described by introducing a super-liquid covering the whole surface. Using this condition together with the conditions that the Gibbs-Helmholtz equation applies and that the entropy sum is constant, the thicknesses of the layer of super-liquid and the tension layer have been calculated. In the case of water, the thickness of the layer of super-water is 660 Å, while the thickness of the tension layer is monoatomic in all materials. The cause of surface tension is an electromagnetic force exerted by the super-liquid on the interfacial normal liquid; high-frequency attractive and repulsive forces make the interfacial atoms approach each other, forming a two-dimensional ordered structure. The restoring force of the constituent particles in the tension layer produces the surface tension.
Assessment of Radiological Image Quality by Redundancy: Subject Contrast
Authors: Inatsu Hiroshi , Uchida Suguru , Ohtsuka Akiyoshi
Published: November 2005

The relationship between the subject contrast and the total image performance of a radiograph can be assessed by a single number. In this study, the radiological image quality containing object information in two screen-film systems was assessed by the redundancy, C(Y). The quantity C(Y) in the LTII-QS system has a lower value at low subject contrast but a higher value at high subject contrast, compared with the LHII-RX system. The value of C(Y) is affected more by the radiographic mottle of the system at low subject contrast and more by the MTF of the system at high subject contrast.
The Interaction of Low-Energy Negative Pions with Nuclear Emulsion
Authors: Nagoshi Chieko
Published: November 2005

ET6B emulsions 200 µm thick were exposed to 65 MeV and 379 MeVπ- beams, and the range-energy relations of π- in emulsion for the energy region from 50 MeV to 10 MeV were obtained. The multiplicity and energy spectra of charged particles from pion absorption in emulsion were measured with a 65 MeVπ- beam. The multiplicity of charged particles was also measured with a 379 MeVπ- beam. The experimental results were compared with calculations by the evaporation and cascade theory. The experimental setup and the conditions for the processing of the emulsion to study the pion-nucleus interaction are reported.
Proton Irradiation Damage in GaAs Single Crystals Examined for Solar Cells
Authors: Yamaguchi Masafumi , Yamamoto Akio , Shibukawa Atsushi
Published: November 2005

In this study, high-energy proton (0.5–2 MeV) irradiation damage in GaAs solar cells and single crystals was compared with 60Co γ-ray irradiation damage. The minority carrier diffusion length in proton-irradiated GaAs single crystals can be evaluated from the photovoltaic effect of solar cells. The damage rate in GaAs due to proton irradiation equivalent to that due to 60Co γ-ray irradiation was determined experimentally. The dependence of the damage rate on the proton energy and changes in the solar cell spectral reponse show that high-energy protons above 1 MeV produce uniform damage in a GaAs solar cell active layer, and most low-energy proton irradiation damage is confined within the surface layer. The behavior of proton irradiation damage in GaAs on annealing was also examined.
Temperature Measurements of the Reflected Shock Region by the Time-of-Flight Method
Authors: Teshima Koji , Takahashi Norio
Published: November 2005

Reflected shock temperatures were measured by sampling a small volume of gas through a nozzle into a vacuum to yield a molecular beam, and applying the time-of-flight method to the beam. The temperatures obtained in this way agree with the frozen temperatures calculated from the incident shock velocities.
Pretransitional Anomaly in Shear Ultrasonic Measurements in the Nematic Phase near TAN
Authors: Kawamura Yasuaki , Okano Koji
Published: November 2005

In the nematic phase near the smectic A phase, a small but finite shear elasticity was observed by shear ultrasonic measurements at frequencies around 105 Hz in p-cyanobenzylidene-p'-n-octyloxyaniline. The observed apparent shear modulus was ∼104 cgs, or equivalently ∼102 poise of the imaginary part of the complex shear viscosity, at 1 K above the nematic-smectic A phase transition temperature. The observed elasticity is mainly attributable to the direct coupling of the shear flow with the smectic order parameter.
Thermal Oxidation of Amorphous Silicon-Germanium-Boron Alloy
Authors: Murase Katsumi , Ogino Toshio , Mizushima Yoshihiko
Published: November 2005

Amorphous Si–Ge–B prepared by low pressure CVD is thermally oxidized much faster than crystalline Si in a wet oxygen ambient. Oxidation rates more than ten times as large as those for crystalline Si are obtained. The oxidation rate increases with increasing B content in starting a-Si–Ge–B films, whereas it decreases with increasing Ge content. It is deduced from infrared absorption and Auger electron spectra that Si–Ge–B oxides are substantially composed of Si, B and O. In contrast to conventional CVD borosilicate glasses prepared at 300–400°C , Si–Ge–B oxides are very stable to high humidity. Electrical properties such as resistivity, maximum dielectric strength and dielectric loss are comparable to those of high quality SiO2. A model of oxidation is proposed and discussed.
Phase Relation in the CuAu1-yPty Quasi-Binary System
Authors: Nakahigashi Kiyotaka , Shinoya Yoshiyuki
Published: November 2005

The crystal structure of CuAu1-y
Pt
y
(0≤y≤1) was studied by X-ray diffractometry. In this alloy system, an L10-type ordered state (0≤y<0.42), a two-phase state of L10+L11(0.42<y<0.96) and an L11-type ordered state (0.96≤y≤1) were observed.
The internal energy of the quasi-binary AB1-y
C
y
having the L10- and L11-type structures is expressed in terms of the Morse potential function. The potential parameters were determined so as to produce the best fit to the observed change with composition in the axial ratio c
0/a
0 of the L10-type structure. Using these parameters, the lattice constants of the respective phases were calculated.
Temperature Variations of Elastic Moduli up to Eutectic Temperature in Tin-Bismuth Alloys
Authors: Kamioka Hiroaki
Published: November 2005

The elastic moduli of tin, bismuth and tin-bismuth alloys of three different chemical compositions (Bi/Bi+Sn)=57.0, 63.5 and 66.7 weight %) were measured by ultrasonic transmission in the temperature range from room temperature to 139°C, which is the eutectic temperature of tin-bismuth alloy. From measured elastic data, the elastic properties of aggregate on metal alloy are reported, and are discussed on the basis of the Hashin-Shtrikman theory.
Effect of Resistivity of CdS Sintered Film on Photovoltaic Properties of Screen-Printed CdS/CdTe Solar Cell
Authors: Uda Hiroshi , Matsumoto Hitoshi , Kuribayashi Kiyoshi , Komatsu Yasumasa , Nakano Akihiko , Ikegami Seiji
Published: November 2005

The preparation conditions of low-resistance CdS sintered film and the effect of the resistance of CdS film on the photovoltaic properties of screen-printed CdS/CdTe solar cells were studied. CdS films were sintered in an alumina case with a perforated cover, and the rate of evaporation of CdCl2 in a printed CdS film was found to be influenced by the area of the holes in the cover. The resistivity of CdS film was less than 0.5 Ω-cm for the samples sintered with the cover (cover area is 102 cm2) which had a hole area between 0.4 and 1.4 cm2. CdS/CdTe solar cells prepared from CdS films with resistivities of about 0.3, 0.7 and 1.4 Ω-cm had conversion efficiencies of 8, 6 and 4% respectively. The decrease in efficiency was due to the increase in series resistance, which depended on the sheet resistance of the CdS film.
Cathodoluminescence Enhancement by Coagulation of Phosphor Particles
Authors: Kano Tsuyoshi , Uchida Yoko
Published: November 2005

The cathodoluminescence intensity of Y2O2S:Eu phosphor settled on nesa-coated glass plates was measured from both the gun side and the glass side. The packing density of the phosphor screens was varied by using coagulating agents during the sedimentation process. As the packing densities decreased, enhancement of the luminescence of up to 6%, was observed. This enhancement is explained by the capture of back-scattered electrons at the rough screen surfaces of the coagulated phosphor.
Temperature Dependence of Anomalous Loop in Double-Layered Amorphous GdCo Film
Authors: Tsujimoto Hiroaki , Sakurai Yoshifumi
Published: November 2005

The magnetic properties of double-layered amorphous GdCo film consisting of films with different compensation temperatures were studied.
The theoretical hysteresis loops and their temperature dependence were deduced using the double-layer model.
It was confirmed that the magnetic properties of the double-layered amorphous GdCo film agreed well with the prediction by the double-layer model.
From the temperature dependence of the double-layered film, it is shown that an apparent compensation temperature exists between the original compensation temperatures in each layer.
The appearance of the inverted loop is explained using the double-layer model; this was confirmed by experiments in the double-layered amorphous GdCo film.
Stabilization of White Light Laser Output by a Floating Metal Grid
Authors: Fujii Kan-ichi , Otaka Masahiro , Kamo Yushi , Takashima Masatake
Published: November 2005

The effect of a metal grid at a floating potential distributed between the anode and negative glow, on the stabilization of He–Cd+ hollow cathode white light laser oscillation, was investigated. The current pulses due to the transition between glow and arc discharges are suppressed by the floating grid, resulting in only a few current pulses during one hour's running time, while several pulses a minute occurred in previous laser tube systems. The signal-to-noise ratio of the three-color laser output is distributed around 30 dB, being 46 dB for the discharge current.
Limit of the Frequency Stability in AlGaAs Semiconductor Lasers
Authors: Tsuchida Hidemi , Tako Toshiharu
Published: November 2005

A theoretical analysis is presented on the limit of the frequency stability in AlGaAs semiconductor lasers. The theoretical stability is derived taking into account the various limiting factors, which include the quantum noise of the lasers, noise of a photodetector and modulation of the laser frequency. The estimated stability is then compared with the experimental results. It is found that the stability can be improved to the quantum noise level when a Fabry-Perot interferometer is used as a frequency reference, and that the stability is limited not only by the quantum noise but also the noise of a photodetector and frequency modulation when atomic or molecular absorption lines are used.
Frequency Response of the Strong Inversion Layer in a Silicon Wafer
Authors: Munakata Chusuke
Published: November 2005

Equations for the inversion capacitance and inversion conductance are proposed. These equations introduce an independent response time-constant. By applying these equations to a metal-oxide-Si diode, the diode capacitance equation is derived. This equation well explains both frequency and bias voltage dependencies of the diode capacitance. A time-constant of 0.21 s is obtained for a previous experiment applying this equation.
Device Modeling for Recessed Oxide Isolation in Bipolar LSIs
Authors: Kotani Norihiko , Kawazu Satoru
Published: November 2005

As the packing density of LSIs (Large Scale Integrated Circuits) increases, it becomes more and more important to reduce the isolation distance between devices, especially in bipolar LSIs.
At high packing densities, however, manufacturing processes become so complex that experimental optimization of each process is extremely difficult.
In view of this situation, we have devised a bipolar model that includes impact ionization to investigate how the isolation breakdown voltage is influenced by field doping and recessed oxidation.
The device model described here is shown to be very effective in optimizing a number of process parameters.
Purity-Sensitive Dark and Photoconductivity in Trans-Polyacetylene
Authors: Miura Muneyuki , Kamagami Shin-ichi , Takezoe Hideo , Fukuda Atsuo , Kuze Eiichi
Published: November 2005

The photoinduced current was measured in the range 0.5–3.4 eV in undoped trans-polyacetylene of various grades of sample quality. It is shown that careful purification of acetylene gas and distillation of Ti(OBu)4 greatly decrease the photoinduced current as well as the dark current. The lowest dark conductivity obtained is 2×10-8 Ω-1cm-1, which is two orders of magnitude lower than that reported as the room-temperature conductivity. The peak at 1.4 eV in the photoinduced current spectrum is conspicuous in better samples, and its origin is regarded as intrinsic. The temperature dependences of the dark and the photoinduced current were measured, and from this the existence of a bolometric spectral region was confirmed.
Micro-Angle Adjusting Device Using PMN Electrostrictors
Authors: Aizawa Motoya , Uchino Kenji , Nomura Shoichiro
Published: November 2005

A micro-angle adjusting system has been constructed with a position actuator “inchworm” and a turntable; the former was fabricated from an electrostrictive unimorph and two electromagnets. The rotation angular velocity can be controlled by changing the voltage applied to the unimorph and the driving frequency, and it has an angle step up to 6×10-4 rad/step.