Mitsui, Takaya; Seto, Makoto; Masuda, Ryo
Japanese Journal of Applied Physics, Part 2, 46(38), p.L930 - L932, 2007/10
A variable-frequency Fe nuclear monochromator has been developed using a pure nuclear Bragg reflection from an oscillating FeBO single crystal at the Nel temperature. The Doppler-shifted single-line Fe Mssbauer radiation at a fixed beam position was successfully filtered using the third-generation synchrotron radiation (SR) of SPring-8. We describe the principle of the variable-frequency Mssbauer filtering technique, the study on the beam characteristics, and some demonstrative experiments on energy-domain SR Mssbauer spectroscopy.
Mitsui, Takaya; Seto, Makoto; Masuda, Ryo; Kiriyama, Koji; Kobayashi, Yasuhiro*
Japanese Journal of Applied Physics, Part 2, 46(28), p.L703 - L705, 2007/07
Synchrotron radiation Mssbauer spectroscopy was performed using a pure nuclear Bragg reflection of a FeBO singlecrystal at the Nel temperature and a Bragg reflection of an oscillating Si single crystal. The developed optical systemfor nuclear diffraction could produce a Doppler-shifted 14.4 keV single-line Fe-Mssbauer radiation and it enabled us to observe the energy-domain synchrotron radiation Mssbauer spectrum with an absorber at rest.
Mitsui, Takaya; Seto, Makoto; Hirao, Naohisa*; Oishi, Yasuo*; Kobayashi, Yasuhiro*; Higashitaniguchi, Satoshi*; Masuda, Ryo*
Japanese Journal of Applied Physics, Part 2, 46(16), p.L382 - L384, 2007/04
Energy-domain synchrotron radiation Mssbauer spectroscopy was performed by a single-line Mssbauer filtering technique and focusing X-ray optics. Pure nuclear Bragg reflection from a heated FeBO single crystal was used for a neV order bandwidth ultrahigh energy resolution X-ray analyzer. As an example of small target research, the Mssbauer transmission spectrum of polycrystalline iron metal was observed using a diamond anvil cell at multimegabar pressures (252 GPa) for the first time.
Lee, C. G.; Iguchi, Kazunari; Esaka, Fumitaka; Magara, Masaaki; Sakurai, Satoshi; Usuda, Shigekazu
Japanese Journal of Applied Physics, Part 2, 45(42), p.L1121 - L1123, 2006/11
no abstracts in English
Uehara, Kazuya; Tsuzuki, Kazuhiro; Amemiya, Hiroshi*; Nagashima, Yoshihiko*; Hoshino, Katsumichi; Sadamoto, Yoshiro*
Japanese Journal of Applied Physics, Part 2, 45(24), p.L630 - L633, 2006/07
Data for detecting the magnetic flux surfaces at the edge plasma in tokamak are presented. When the magnetic surfaces are moved by the plasma jog, it is observed that a current increment appears in the two set of double probe whose front surfaces are shifted by a small distance and that the difference of these two currents through the differential amplifier giving a signal of the arrival of the separatrix also appears, where we refer the separatrix point as a typical position of the magnetic flux surfaces. It is confirmed that magnetic flux surfaces are located by a few cm outward from that calculated by the eqfit-code (EQFIT) and the absolute value of its deviation is identified. This identification is supported by the result of observation of the correlation of the floating potential fluctuation between two different points using one probe pin of the same differential double probe. The ion temperature and the space potential are observed by the another use of the differential double probe are modified following the estimated real magnetic surfaces positions.
Kudo, Hiroshi*; Iwasaki, Wataru*; Uchiyama, Rumi*; Tomita, Shigeo*; Shima, Kunihiro*; Sasa, Kimikazu*; Ishii, Satoshi*; Narumi, Kazumasa; Naramoto, Hiroshi; Saito, Yuichi; et al.
Japanese Journal of Applied Physics, Part 2, 45(22), p.L565 - L568, 2006/06
The first observation of the energy distribution of electrons emitted from solids bombarded by MeV atom clusters is reported. In the backward direction, using graphite and Si bombarded by C and Al (n 8), an appreciable suppression of electron emission has been observed at electron energies lower than 10 eV. Electron yield per atom decreases with increasing n, and becomes less than 50% at n 3, relative to the case of n = 1. The experimental results cannot be explained in terms of projectile stopping cross sections nor by the clearing-the-way effect. It is probable that the suppressed electron emission is a result of the suppression of the transport or surface transmission of the produced low-energy electrons, rather than of the suppression of ionization.
Lee, C. G.; Iguchi, Kazunari; Esaka, Fumitaka; Magara, Masaaki; Sakurai, Satoshi; Watanabe, Kazuo; Usuda, Shigekazu
Japanese Journal of Applied Physics, Part 2, 45(10), p.L294 - L296, 2006/03
We have developed an effective method for fission track (FT) sample preparation to perform particle analysis of the safeguards environmental samples by the FT-thermal ionization mass spectrometry (TIMS) method. In this method, a fission track detector and the layer containing particles are separated. The main feature of the developed FT sample is that the detection of a particle from the corresponding fission track can be performed correctly and in a simple manner by fixing each one end of the detector and the particle layer and by using an etching tool. It is expected that this method will enhance the effectiveness of particle analysis.
Togashi, Hideaki*; Asaoka, Hidehito; Yamazaki, Tatsuya; Suemitsu, Maki*
Japanese Journal of Applied Physics, Part 2, 44(45), p.L1377 - L1380, 2005/10
no abstracts in English
Sato, Masayasu; Isayama, Akihiko; Iwama, Naofumi*; Kawahata, Kazuo*
Japanese Journal of Applied Physics, Part 2, 44(21), p.L672 - L675, 2005/05
no abstracts in English
Esaka, Konomi; Esaka, Fumitaka; Inagawa, Jun; Iguchi, Kazunari; Lee, C. G.; Sakurai, Satoshi; Watanabe, Kazuo; Usuda, Shigekazu
Japanese Journal of Applied Physics, Part 2, 43(7A), p.L915 - L916, 2004/07
An effective method for isotope ratio analysis of individual particles containing uranium in safeguards swipe samples was developed by using a fission track (FT) technique combined with thermal ionization mass spectrometry (TIMS). The particles in the sample were directly recovered onto a polycarbonate membrane filter, which was set in a filtration system. After the particle recovery, the filter was dissolved to form a non-coated FT detector film containing the particles. Individual particles containing uranium were then identified by the observation of fission tracks created by thermal neutron irradiation. By combination of the FT technique with TIMS, isotope ratios of uranium for individual particles in the swipe sample prepared from a uranium standard reference material could be effectively determined.
Saito, Hiroyuki; Utsumi, Wataru; Kaneko, Hiroshi*; Aoki, Katsutoshi
Japanese Journal of Applied Physics, Part 2, 43(7B), p.L981 - L983, 2004/07
Bulk specimens of AlGaN alloys covering a composition range of 01 were synthesized by a solid-phase reaction under high pressure. X-ray diffraction profiles were measured to observe the alloying process, which began at around 800C under 6.0 GPa. SEM observation and X-ray analysis of the recovered specimen indicated a uniform distribution of Al and Ga and continuous variations of the lattice constants against the composition, which implies that a solid solution of AlN and GaN is formed regardless of atomic composition.
Usuda, Manabu; Hamada, Noriaki*; Shiraishi, Kenji*; Oshiyama, Atsushi*
Japanese Journal of Applied Physics, Part 2, 43(3B), p.L407 - L410, 2004/03
We report first-principles electronic band-structure calculations of InN by using the all-electron full-potential linearized augmented-plane-wave (FLAPW) method in the approximation (GWA), and provide the reliable theoretical bandgap of InN. Our calculation suggests that InN is a narrow-gap semiconductor and strongly supports the recently reported smaller bandgaps.
Japanese Journal of Applied Physics, Part 2, 42(8A), p.L974 - L976, 2003/08
A first-order transform matrix is proposed to calculate electron beam emittance dilution arising from coherent synchrotron radiation (CSR) in a next-generation light source based on an energy-recovery linac. The matrix approach enable us to scan a lot of parameters for the design of achromatic cells of minimum emittance dilution. The emitatce dilution can be minimized when the CSR wake dispersion matches to the betatron function envelope at the achromatic cell exit.
Oshima, Takeshi; Lee, K. K.; Ishida, Yuki*; Kojima, Kazutoshi*; Tanaka, Yasunori*; Takahashi, Tetsuo*; Yoshikawa, Masahito; Okumura, Hajime*; Arai, Kazuo*; Kamiya, Tomihiro
Japanese Journal of Applied Physics, Part 2, 42(6B), p.L625 - L627, 2003/06
The n-channel Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs) were fabricated on cubic silicon carbide (3C-SiC) epitaxial layers grown on 3C-SiC substrates. The gate oxide of the MOSFETs was formed using pyrogenic oxidation at 1100C. The 3C-SiC MOSFETs showed enhancement type behaviors after annealing at 200C for 30 min in argon atmosphere. The maximum value of the effective channel mobility of the 3C-SiC MOSFETs was 260 cm/Vs. The leakage current of gate oxide was of a few tens of nA/cm at an electric field range below 8.5 MV/cm, and breakdown began around 8.5 MV/cm.
Matsubara, Masakazu*; Yamaki, Tetsuya; Ito, Hisayoshi; Abe, Hiroaki*; Asai, Keisuke*
Japanese Journal of Applied Physics, Part 2, 42(5A), p.L479 - L481, 2003/05
Pulsed laser ablation with a KrF excimer laser was used to prepare fine particles of titanium dioxide (TiO). The ablation in an atmosphere of Ar and O (5:5) at total pressures of 1 Torr led to the formation of TiO nanoparticles composed of anatase and rutile structures without any suboxides. The weight fraction of the rutile/anatase crystalline phases was controlled by the pressure of the Ar/O gas. The TiO nanoparticles had a spherical shape and their size, ranging from 10 and 14 nm, also appeared to be dependent on the ambient pressure.
Isayama, Akihiko; Iwama, Naofumi*; Hosoda, Yosuke*; Satake, Shinsuke*; Isei, Nobuaki; Ishida, Shinichi; Sato, Masayasu
Japanese Journal of Applied Physics, Part 2, 42(3), p.L329 - L331, 2003/03
no abstracts in English
Oba, Masaki; Kato, Masaaki; Maruyama, Yoichiro
Japanese Journal of Applied Physics, Part 2, 41(8A), p.L881 - L883, 2002/08
Optical parametric oscillator using a periodically poled KTP as a gain medium pumped by a pulsed Nd:YAG green laser of which maximum pulse repetition frequency is 100 Hz is demonstrated. Output energy of 5.8 mJ at the pulse repetition frequency of 100 Hz with the conversion efficiency of about 40% is obtained by double-pass pumping scheme. Threshold pumping energy is 1.6 mJ of which peak power is as low as 18 MW/cm. At the pulse repetition frequency between 10 Hz and 100 Hz, the conversion efficiency is almost constant and undesirable thermal effects are not observed.
Kawakita, Shiro*; Imaizumi, Mitsuru*; Yamaguchi, Masafumi*; Kushiya, Katsumi*; Oshima, Takeshi; Ito, Hisayoshi; Matsuda, Sumio*
Japanese Journal of Applied Physics, Part 2, 41(7A), p.L797 - L799, 2002/07
Recovery of electrical characteristics of Cu(In,Ga)Se irradiated with protons was studied. A proton irradiation chamber which has a AM0 solar light was used for in-situ measurement in this study. The electrical characteristics of irradiated samples which were kept under a dark condition recovered. Furthermore,this recovery effect was enhanced by light illumination. The activation energy for the recovery was estimated to be 0.80 eV (light illumination case) and 0.92 eV (dark condition case).
Abe, Hideki*; Yoshii, Kenji
Japanese Journal of Applied Physics, Part 2, 41(6B), p.L685 - L687, 2002/06
no abstracts in English
Lu, P.; Kawachi, Tetsuya; Suzuki, M.*; Sukegawa, Kota*; Namba, Shinichi; Tanaka, Momoko; Hasegawa, Noboru; Nagashima, Keisuke; Daido, Hiroyuki; Arisawa, Takashi; et al.
Japanese Journal of Applied Physics, Part 2, 41(2A), p.L133 - L135, 2002/02
no abstracts in English