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Miura, Daisuke*; Kumada, Takayuki; Sekine, Yurina; Motokawa, Ryuhei; Nakagawa, Hiroshi; Oba, Yojiro; Ohara, Takashi; Takata, Shinichi; Hiroi, Kosuke; Morikawa, Toshiaki*; et al.
Journal of Applied Crystallography, 54(2), p.454 - 460, 2021/04
Times Cited Count:1 Percentile:16.63(Chemistry, Multidisciplinary)We developed a spin-contrast-variation neutron powder diffractometry technique that extracts the structure factor of hydrogen atoms, namely, the contribution of hydrogen atoms to a crystal structure factor. Crystals of L-glutamic acid were dispersed in a dpolystyrene matrix containing 4-methacryloyloxy-2,2,6,6,-tetramethyl-1-piperidinyloxy (TEMPO methacrylate) to polarize their proton spins dynamically. The intensities of the diffraction peaks of the sample changed according to the proton polarization, and the structure factor of the hydrogen atoms was extracted from the proton-polarization dependent intensities. This technique is expected to enable analyses of the structures of hydrogen-containing materials that are difficult to determine with conventional powder diffractometry.
Tsai, P.-E.; Heilbronn, L. H.*; Lai, B.-L.*; Iwata, Yoshiyuki*; Murakami, Takeshi*; Sheu, R.-J.*
Nuclear Instruments and Methods in Physics Research B, 449, p.62 - 70, 2019/06
Times Cited Count:3 Percentile:31.66(Instruments & Instrumentation)The secondary neutrons produced from 100- and 230-MeV/nucleon He ions, respectively, stopping in the thick iron, PMMA and water targets are measured by the time of flight method combined with the pulse shape discrimination of liquid scintillators. The experimental data show that the secondary neutrons were contributed from breakup of projectiles, emission from overlap regions of projectile nuclei and target nuclei, and evaporation of projectiles and target nuclei. The measured double-differential thick target neutron yields, angular distributions, and total neutron yields per ion, were benchmarked by the PHITS, FLUKA, and MCNP model calculations. The default models in these codes agree the experimental data well at intermediate-to-large angles in the low-to-intermediate energy range. However, the physics models implemented in PHITS need further improvement for some particular nuclear interaction mechanisms, and this work can be an importance reference for future model development.
Zegers, R. G. T.*; Sumihama, Mizuki*; Ahn, D. S.*; Ahn, J. K.*; Akimune, Hidetoshi*; Asano, Yoshihiro; Chang, W. C.*; Dat, S.*; Ejiri, Hiroyasu*; Fujimura, Hisako*; et al.
Physical Review Letters, 91(9), p.092001_1 - 092001_4, 2003/08
Times Cited Count:128 Percentile:94.86(Physics, Multidisciplinary)no abstracts in English
Nakano, Takashi*; Ahn, D. S.*; Ahn, J. K.*; Akimune, Hidetoshi*; Asano, Yoshihiro; Chang, W. C.*; Date, S.*; Ejiri, Hiroyasu*; Fujimura, Hisako*; Fujiwara, Mamoru; et al.
Physical Review Letters, 91(1), p.012002_1 - 012002_4, 2003/07
Times Cited Count:1007 Percentile:99.86(Physics, Multidisciplinary)no abstracts in English
Chitose, Hiromasa*; Watanabe, Satoshi*; Sadamatsu, Hideaki*; Iwata, Yutaka*; Kaji, Yoshiyuki; Nemoto, Yoshiyuki
no journal, ,
We researched the recent enhancements of regulations and solutions related Spent Fuel Pool safety and reported the analytical results about problems and evaluation procedures related effectiveness evaluation of safety measures.
Kaji, Yoshiyuki; Nemoto, Yoshiyuki; Takase, Kazuyuki; Tojo, Masayuki*; Goto, Daisuke*; Iwata, Yutaka*; Otake, Yukihiko*; Nishimura, Satoshi*; Suzuki, Hiroaki*
no journal, ,
We will make quantitatively clear the phenomenon of fuel air oxidation mechanism, fuel failure mechanism after loss of coolant and criticality risks during and after sever accidents of Spent Fuel Pool(SFP) and clarify the quantitative effects of enhancements of SFP safety such as Spray and fuel loading patterns. We will report the whole plan in this presentation.
Tsai, P.-E.; Heilbronn, L.*; Lai, B. L.*; Iwata, Yoshiyuki*; Murakami, Takeshi*; Ogawa, Tatsuhiko; Sheu, R.-J.*
no journal, ,
The thick target neutron yields from 100- and 230-MeV/nucleon helium ions bombarding water, PMMA, and iron targets were measured by using the time-of-flight technique at 0 to 121. The experimental data were compared with INCL-4.6, RQMD, and ISABEL model calculations respectively by the PHITS, FLUKA, and MCNP6 codes. The model calculations of the neutron yields generally agree with the measurements, especially in the intermediate and low energy regions at angles at and above 30 degrees. However, some disagreements exist not only between the data and the simulations but also between models. The benchmark results will be used for further improvement of the PHITS code in the future.