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Yokoyama, Sumi*; Tsujimura, Norio; Hashimoto, Makoto; Yoshitomi, Hiroshi; Kato, Masahiro*; Kurosawa, Tadahiro*; Tatsuzaki, Hideo*; Sekiguchi, Hiroshi*; Koguchi, Yasuhiro*; Ono, Koji*; et al.
Journal of Radiation Protection and Research, 47(1), p.1 - 7, 2022/03
Background: In Japan, new regulations that revise the dose limit for the lens of the eye (the lens), operational quantities, and measurement positions for the lens dose were enforced in April 2021. Based on the international safety standards, national guidelines, the results of the Radiation Safety Research Promotion Fund of the Nuclear Regulatory Authority, and other studies, the Working Group of Radiation Protection Standardization Committee, the Japan Health Physics Society (JHPS) developed a guideline for radiation dose monitoring for the lens. Materials and Methods: The Working Group of the JHPS discussed the criteria of non-uniform exposure and the management criteria set to not exceed the dose limit for the lens. Results and Discussion: In July 2020, the JHPS guideline was published. The guideline consists of three parts: main text, explanations, and 26 questions. In the questions, the corresponding answers were prepared, and specific examples were provided to enable similar cases to be addressed. Conclusion: With the development of guideline on radiation dose monitoring of the lens, radiation managers and workers will be able to smoothly comply with revised regulations and optimise radiation protection.
Yokoyama, Sumi*; Iwai, Satoshi*; Tsujimura, Norio; Hashimoto, Makoto; Yoshitomi, Hiroshi; Kato, Masahiro*; Kurosawa, Tadahiro*; Tatsuzaki, Hideo*; Sekiguchi, Hiroshi*; Koguchi, Yasuhiro*; et al.
Proceedings of 15th International Congress of the International Radiation Protection Association (IRPA-15) (Internet), 8 Pages, 2022/00
Kofu, Maiko; Hashimoto, Naoki*; Akiba, Hiroshi*; Kobayashi, Hirokazu*; Kitagawa, Hiroshi*; Iida, Kazuki*; Nakamura, Mitsutaka; Yamamuro, Osamu*
Physical Review B, 96(5), p.054304_1 - 054304_7, 2017/08
Times Cited Count：12 Percentile：54.99(Materials Science, Multidisciplinary)The vibrational states of hydrogen atoms in bulk and nanocrystalline palladium were examined in a wide energy region 
meV using neutron spectroscopy. In bulk PdH
, the vibrational excitations of H atoms were roughly reproduced by the quantum harmonic oscillator (QHO) model. In PdH
nanocrystals with a diameter of 8 nm, however, additional vibrational excitations were found at energies above 80 meV. The energies and intensities of the additional states were not explained by QHO but reasonably described as vibrations in a highly anharmonic trumpet-like potential. The additional excitations are attributed to the vibrations of H atoms at tetrahedral sites in the subsurface region stabilized by surface effects. This is an experimental work which clearly detects hydrogen vibration 
metal nanoparticles.
Yamamoto, Kazami; Hayashi, Naoki; Okabe, Kota; Harada, Hiroyuki; Saha, P. K.; Yoshimoto, Masahiro; Hatakeyama, Shuichiro; Hotchi, Hideaki; Hashimoto, Yoshinori*; Toyama, Takeshi*
Proceedings of 54th ICFA Advanced Beam Dynamics Workshop on High-Intensity, High Brightness and High Power Hadron Beams (HB 2014) (Internet), p.278 - 282, 2015/03
Rapid Cycling Synchrotron (RCS) of Japan Proton Accelerator Complex (J-PARC) is providing more than 300 kW of proton beam to Material and Life science Facility (MLF) and Main Ring (MR). Last summer shutdown, a new ion source was installed to increase output power to 1 MW. In order to achieve reliable operation of 1 MW, we need to reduce beam loss as well. Beam quality of such higher output power is also important for users. Therefore we developed new monitors that can measure the halo with higher accuracy. We present beam monitor systems for these purposes.
Makhsun*; Hashimoto, Takuya*; Sakuma, Takashi*; Takahashi, Haruyuki*; Kamishima, Osamu*; Igawa, Naoki; Danilkin, S. A.*
Journal of the Physical Society of Japan, 83(7), p.074602_1 - 074602_4, 2014/07
Times Cited Count：2 Percentile：20.69(Physics, Multidisciplinary)The correlations of atomic thermal displacements in Al were obtained from the analysis of diffuse neutron scattering intensity. The interatomic force constants were determined from the correlation effects using a newly introduced equation. The derived force constants and the crystal structure of Al were used to estimate the phonon dispersion relations, phonon density of states, and specific heat by computer simulation. The calculated phonon dispersion relations and specific heat of Al are similar to those obtained from inelastic neutron scattering and specific heat measurements, respectively.
Hatakeyama, Shuichiro; Hayashi, Naoki; Arakawa, Dai*; Hashimoto, Yoshinori*; Hiramatsu, Shigenori*; Odagiri, Junichi*; Sato, Kenichiro*; Tejima, Masaki*; Tobiyama, Makoto*; Toyama, Takeshi*; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2698 - 2700, 2010/05
The Data Acquisition System of Beam Position Monitors (BPMs) in J-PARC Main Ring are consist of 186 Linux-based Data Processing Circuits (BPMCs) and 12 EPICS IOCs. They are important tool to see the COD and turn-by-turn beam positions. This report describes the process of the data reconstruction which include how the various calibration constants are applied.
Tejima, Masaki*; Arakawa, Dai*; Hashimoto, Yoshinori*; Sato, Kenichiro*; Toyama, Takeshi*; Yamamoto, Noboru*; Hayashi, Naoki; Hanamura, Kotoku*
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.978 - 980, 2010/05
To maintain the beam orbit of beam transport line from RCS to MR in J-PARC (3-50BT), 14 beam position monitors (BPMs) were installed. Their signals gathered in the local control building (D01) have been measured by using 14 digitizing oscilloscopes. The data acquisition system have a performance of shot-by-shot measurement.
Toyama, Takeshi*; Arakawa, Dai*; Hiramatsu, Shigenori*; Igarashi, Susumu*; Lee, S.*; Matsumoto, Hiroshi*; Odagiri, Junichi*; Tejima, Masaki*; Tobiyama, Makoto*; Hashimoto, Yoshinori*; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.981 - 983, 2010/05
Experiences of operating BPM's during beam commissioning at the J-PARC MR are reported. The subjects are: (1) bug report, statistics and especially the effect of a beam duct step, (2) position resolution estimation (
30 micrometers with 1 sec averaging), (3) beam based alignment.
Hayashi, Naoki; Hiroki, Seiji; Sato, Kenichiro; Toyokawa, Ryoji; Arakawa, Dai*; Lee, S.*; Hashimoto, Yoshinori*; Miura, Takako*; Toyama, Takeshi*
KEK Proceedings 2006-15 (CD-ROM), p.128 - 130, 2007/03
The beam diagnostics system for J-PARC synchrotrons (RCS and MR) will be presented. The design of the system will be described for high current machines. Some test results will be reported.
F by a laser albation of LiF-Li
N mixtureYokoyama, Keiichi; Haketa, Naoki*; Hashimoto, Masashi; Furukawa, Katsutoshi; Tanaka, Hiromasa*; Kudo, Hiroshi*
Chemical Physics Letters, 320(5-6), p.645 - 650, 2000/04
Times Cited Count：35 Percentile：71.58(Chemistry, Physical)no abstracts in English
Komatsu, Hisanori*; Matsuda, Yasuhiro*; Oki, Saiko*; Hashimoto, Naoki*; Okuyama, Katsushi*; Yamamoto, Hiroko*; Nomachi, Masaharu*; Sugaya, Yorihito*; Yasuda, Keisuke*; Sato, Takahiro; et al.
no journal, ,
no abstracts in English
Matsuda, Yasuhiro*; Okuyama, Katsushi*; Komatsu, Hisanori*; Oki, Saiko*; Hashimoto, Naoki*; Sano, Hidehiko*; Yamamoto, Hiroko*; Iwami, Yukiteru*; Hayashi, Mikako*; Nomachi, Masaharu*; et al.
no journal, ,
no abstracts in English
Kofu, Maiko; Hashimoto, Naoki*; Akiba, Hiroshi*; Kobayashi, Hirokazu*; Kitagawa, Hiroshi*; Tyagi, M.*; Faraone, A.*; Copley, J.*; Lohstorh, W.*; Iida, Kazuki*; et al.
no journal, ,
no abstracts in English
