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Noda, Yohei*; Koizumi, Satoshi*; Masui, Tomomi*; Mashita, Ryo*; Kishimoto, Hiromichi*; Yamaguchi, Daisuke; Kumada, Takayuki; Takata, Shinichi; Oishi, Kazuki*; Suzuki, Junichi*
Journal of Applied Crystallography, 49(6), p.2036 - 2045, 2016/12
Times Cited Count：19 Percentile：78.58(Chemistry, Multidisciplinary)Okumura, Susumu; Arakawa, Kazuo; Fukuda, Mitsuhiro; Nakamura, Yoshiteru; Yokota, Wataru; Ishimoto, Takayuki*; Kurashima, Satoshi; Ishibori, Ikuo; Nara, Takayuki; Agematsu, Takashi; et al.
Review of Scientific Instruments, 76(3), p.033301_1 - 033301_6, 2005/03
Times Cited Count：9 Percentile：43.09(Instruments & Instrumentation)A magnetic field drift, gradual decrease of the order of 10
in several tens of hours, was observed with the beam intensity decrease in an operation of an azimuthally-varying-field (AVF) cyclotron. From our experimental results, we show that the temperature increase of the magnet iron by the heat transfer from the excitation coils can induce such change of the magnetic field as to deteriorate the beam quality. The temperature control of the magnet iron was realized by thermal isolation between the main coil and the yoke and by precise control of the cooling water temperature of the trim coils attached to the pole surfaces in order to prevent temperature change of the magnet iron. The magnetic field stability of 
5
10
and the beam intensity stability of 2% have been achieved by this temperature control.
Kawasuso, Atsuo; Ishimoto, Takayuki*; Maekawa, Masaki; Fukaya, Yuki; Hayashi, Kazuhiko; Ichimiya, Ayahiko
Review of Scientific Instruments, 75(11), p.4585 - 4588, 2004/11
Times Cited Count：33 Percentile：80.32(Instruments & Instrumentation)A 10 keV positron beam has been developed using coaxially symmetric electromagnetic lenses for reflection high-energy positron diffraction (RHEPD) experiments. The beam brightness is 
10
e
/sec/cm
/rad/V which is comparable to that obtained using brightness enhancement technique. The beam parallel and normal coherence lengths are over 100 
and 40 , respectively, which are long enough to observe diffraction patterns associated with large surface super-structures. RHEPD patterns from a Si(111)-(77) reconstructed surface have been successfully observed with a much better quality than previously reported.
Hasegawa, Noboru; Kawachi, Tetsuya; Utsumi, Takayuki*; Sasaki, Akira; Tanaka, Momoko; Kado, Masataka; Sukegawa, Kota*; Lu, P.; Kishimoto, Maki; Tai, R.; et al.
Japanese Journal of Applied Physics, Part 1, 43(5A), p.2519 - 2522, 2004/05
Times Cited Count：12 Percentile：45.06(Physics, Applied)We conducted high-precision measurements of the wavelength of the nickel-like silver X-ray laser in order to compare it with a theoretical wavelength. The reasons for using this laser are as follows: First, this laser line is in the wavelength region of Mo/Si multi-layer mirrors; therefore, this laser line is important for applications. Second, the strongamplification of this laser line has been obtained in our previous work, and the higher order line in the spectra obtained by our spectrometer can be used. Third, since silver is arelatively low-z material (z = 47), this wavelength is a ideal benchmark of atomic structural codes such as the Multiconfiguration Dirac-Fock (MCDF) code. The wavelength of the nickel-like silver X-ray laser was determined to be 13.887 nm. The comparison with MCDF codes shows that the present experimental result can work as a good benchmark of the accuracy of the codes.
7 surfaceKawasuso, Atsuo; Fukaya, Yuki; Hayashi, Kazuhiko; Maekawa, Masaki; Ishimoto, Takayuki*; Okada, Sohei; Ichimiya, Ayahiko*
Materials Science Forum, 445-446, p.385 - 389, 2004/02
We so far discovered the total reflection and the first Bragg peak in reflection high-energy positron diffraction (RHEPD). However, the fractional order diffractions from reconstructed surfaces have been eluded from the observation. We therefore attempted to get RHEPD patterns from a Si-77 surface. Consequently, the 1/7, 2/7 and 3/7 diffraction rings due to Si(111)-77 reconstruction were clearly found in addition to the zeroth and the first Laue zones. The specular intensity was measured as a function of glancing angle. A small structure was found in the total reflection region. The small structure was attributed to the interference of positron wavefunction because of adatoms. However, the overall intensity profile was not well reproduced using a model already determined in the electron diffraction studies. To reproduce the obtained intensity profile, we may need to modify the vertical positions of the topmost surface and/or the absorption potential due to inelastic scattering processes.
Ishimoto, Takayuki*; Kawasuso, Atsuo; Ito, Hisayoshi; Okada, Sohei
JAERI-Tech 2003-091, 32 Pages, 2003/12
JAERI-Tech-2003-091.pdf:3.96MB
no abstracts in English
Kawasuso, Atsuo; Ishimoto, Takayuki*; Fukaya, Yuki; Hayashi, Kazuhiko; Ichimiya, Ayahiko
e-Journal of Surface Science and Nanotechnology (Internet), 1, p.152 - 157, 2003/12
no abstracts in English
Maekawa, Masaki; Kawasuso, Atsuo; Ishimoto, Takayuki*; Chen, Z. Q.
JAERI-Review 2003-033, TIARA Annual Report 2002, p.297 - 299, 2003/11
no abstracts in English
Okumura, Susumu; Arakawa, Kazuo; Fukuda, Mitsuhiro; Nakamura, Yoshiteru; Yokota, Wataru; Ishimoto, Takayuki; Kurashima, Satoshi; Ishibori, Ikuo; Nara, Takayuki; Agematsu, Takashi; et al.
Nukleonika, 48(Suppl.2), p.S35 - S37, 2003/00
In the JAERI AVF cyclotron, unstable phenomena, such as beam intensity decrease, were observed. We found that an increase in temperature of the iron body of the magnet induced the drift of the magnetic field. Stabilization of the iron body temperature was achieved. We have developed a nuclear magnetic resonance (NMR) magnetometer with an accuracy of the order of 10 to measure the stability of the cyclotron magnetic field with a large gradient by using a pair of correction coils to reduce the field gradient and by eliminating the effect of the RF.
Kawasuso, Atsuo; Ishimoto, Takayuki*; Okada, Sohei; Ito, Hisayoshi; Ichimiya, Ayahiko*
Applied Surface Science, 194(1-4), p.287 - 290, 2002/06
Times Cited Count：6 Percentile：34.98(Chemistry, Physical)no abstracts in English
Ishimoto, Takayuki*; Kawasuso, Atsuo; Ito, Hisayoshi
Applied Surface Science, 194(1-4), p.43 - 46, 2002/06
Times Cited Count：9 Percentile：45.24(Chemistry, Physical)no abstracts in English
Okumura, Susumu; Arakawa, Kazuo; Fukuda, Mitsuhiro; Nakamura, Yoshiteru; Yokota, Wataru; Ishimoto, Takayuki*; Kurashima, Satoshi; Ishibori, Ikuo; Nara, Takayuki; Agematsu, Takashi; et al.
AIP Conference Proceedings 600, p.330 - 332, 2001/00
Frequent corrections of the magnetic field of the JAERI AVF cyclotron were required for keeping a beam current constant during long time operation. We observed correlation between the magnetic field and the temperature of the cyclotron magnet yoke by measuring the magnetic field with an NMR probe and the temperature with platinum resistance thermometers. The unstable phenomenon of a cyclotron beam was induced by temperature change in the magnet yoke caused mainly by thermal conduction from the main coil. To restrain the thermal conduction to the yoke, we have inserted temperature controlled copper plates between the yoke and the main coil. In addition, a temperature control system of the cooling water of the trim coils has been installed independent of the total cooling system for controlling the pole tip temperature. An optimum condition of the temperature control systems for stabilizing the magnetic field has been investigated.
Okumura, Susumu; Kurashima, Satoshi; Ishimoto, Takayuki*; Yokota, Wataru; Arakawa, Kazuo; Fukuda, Mitsuhiro; Nakamura, Yoshiteru; Ishibori, Ikuo; Nara, Takayuki; Agematsu, Takashi; et al.
Proceedings of 13th Symposium on Accelerator Science and Technology, p.283 - 285, 2001/00
no abstracts in English
Yokota, Wataru; Fukuda, Mitsuhiro; Okumura, Susumu; Arakawa, Kazuo; Ishibori, Ikuo; Nara, Takayuki; Agematsu, Takashi; Tamura, Hiroyuki; Kurashima, Satoshi; Nakamura, Yoshiteru; et al.
JAERI-Review 2000-024, TIARA Annual Report 1999, p.273 - 275, 2000/10
no abstracts in English
Kikuchi, Takayuki; Oku, Takayuki; Shinohara, Takenao; Suzuki, Junichi; Ishii, Yuya; Takeda, Masayasu; Kakurai, Kazuhisa; Sasaki, Yuji*; Kishimoto, Mikio*; Yokoyama, Makoto*; et al.
no journal, ,
no abstracts in English
N
measured by polarized neutronsIshii, Yuya; Oitani, Seiki; Takeda, Masayasu; Kakurai, Kazuhisa; Kikuchi, Takayuki; Oku, Takayuki; Shinohara, Takenao; Suzuki, Junichi; Sasaki, Yuji*; Kishimoto, Mikio*; et al.
no journal, ,
no abstracts in English
-Fe and CoFe powder by polarized neutron diffractionOitani, Seiki; Ishii, Yuya; Takeda, Masayasu; Kakurai, Kazuhisa; Kikuchi, Takayuki; Oku, Takayuki; Shinohara, Takenao; Suzuki, Junichi; Yokoyama, Makoto*; Nishihara, Yoshikazu*; et al.
no journal, ,
no abstracts in English
Oku, Takayuki; Kikuchi, Takayuki; Oba, Yojiro; Shinohara, Takenao; Suzuki, Junichi; Ishii, Yuya; Oitani, Seiki; Takeda, Masayasu; Kakurai, Kazuhisa; Yokoyama, Makoto*; et al.
no journal, ,
no abstracts in English
N by polarized neutronsIshii, Yuya; Takeda, Masayasu; Kakurai, Kazuhisa; Kikuchi, Takayuki; Shinohara, Takenao; Oku, Takayuki; Suzuki, Junichi; Sasaki, Yuji*; Kishimoto, Mikio*; Yokoyama, Makoto*; et al.
no journal, ,
no abstracts in English
Kikuchi, Takayuki; Oku, Takayuki; Shinohara, Takenao; Suzuki, Junichi; Ishii, Yuya; Takeda, Masayasu; Kakurai, Kazuhisa; Sasaki, Yuji*; Kishimoto, Mikio*; Yokoyama, Makoto*; et al.
no journal, ,
no abstracts in English
