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Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Yosuke; Yoshida, Makoto*; Hasegawa, Shoichi; Maekawa, Fujio; Iwamoto, Hiroki; Nakamoto, Tatsushi*; Ishida, Taku*; Makimura, Shunsuke*
JPS Conference Proceedings (Internet), 33, p.011050_1 - 011050_6, 2021/03
R&D of the beam window is crucial in the ADS, which serves as a partition between the accelerator and the target region. Although the displacement per atom (DPA) is used to evaluate the damage on the window, experimental data on the displacement cross section is scarce in the energy region above 20 MeV. We started to measure the displacement cross section for the protons in the energy region between 0.4 to 3 GeV. The displacement cross section can be derived by resistivity change divided by the proton flux and the resistivity change per Frankel pair on cryo-cooled sample to maintain damage. Experiments were conducted at the 3 GeV proton synchrotron at the J-PARC Center, and aluminum and copper was used as samples. As a result of comparison between the present experiment and the calculation of the NRT model, which is widely used for calculation of the displacement cross section, it was found that the calculation of the NRT model overestimated the experiment by about 3 times.
Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Yosuke; Yoshida, Makoto*; Hasegawa, Shoichi; Maekawa, Fujio; Iwamoto, Hiroki; Nakamoto, Tatsushi*; Ishida, Taku*; Makimura, Shunsuke*
EPJ Web of Conferences, 239, p.06006_1 - 06006_4, 2020/09
Times Cited Count：0 Percentile：0.1(Nuclear Science & Technology)R&D of the beam window is crucial in the ADS, which serves as a partition between the accelerator and the target region. Although the displacement per atom (DPA) is used to evaluate the damage on the window, experimental data on the displacement cross section is scarce in the energy region above 20 MeV. We started to measure the displacement cross section for the protons in the energy region between 0.4 to 3 GeV. The displacement cross section can be derived by resistivity change divided by the proton flux and the resistivity change per Frankel pair on cryo-cooled sample to maintain damage. Experiments were conducted at the 3 GeV proton synchrotron at the J-PARC Center, and copper was used as samples. As a result of comparison between the present experiment and the calculation of the NRT model, which is widely used for calculation of the displacement cross section, it was found that the calculation of the NRT model overestimated the experiment by about 3 times.
Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Yosuke; Yoshida, Makoto*; Hasegawa, Shoichi; Maekawa, Fujio; Iwamoto, Hiroki; Nakamoto, Tatsushi*; Ishida, Taku*; Makimura, Shunsuke*
JPS Conference Proceedings (Internet), 28, p.061004_1 - 061004_6, 2020/02
no abstracts in English
Ahadi, A.*; Kawasaki, Takuro; Harjo, S.; Ko, W.-S.*; Sun, Q. P.*; Tsuchiya, Koichi*
Acta Materialia, 165, p.109 - 117, 2019/02
Times Cited Count：52 Percentile：95.19(Materials Science, Multidisciplinary)Meigo, Shinichiro; Matsuda, Hiroki; Iwamoto, Yosuke; Iwamoto, Hiroki; Hasegawa, Shoichi; Maekawa, Fujio; Yoshida, Makoto*; Ishida, Taku*; Makimura, Shunsuke*; Nakamoto, Tatsushi*
Proceedings of 9th International Particle Accelerator Conference (IPAC '18) (Internet), p.499 - 501, 2018/06
no abstracts in English
Saito, Toru; Okubo, Toshikazu*; Izumi, Keisuke*; Okawa, Yoshinao*; Kobayashi, Norihiro*; Yamazaki, Toru; Kawano, Katsumi; Isono, Takaaki
Teion Kogaku, 50(8), p.400 - 408, 2015/08
Aramid fiber-reinforced plastic (AFRP) has been developed as a structural material that has the advantages of light weight and high strength. In this study, tensile tests were carried out to measure the tensile properties of AFRP rod on the market for reinforcement of concrete at room temperature, 77 K and 4.2 K. Especially at cryogenic temperatures, it is difficult to perform a tensile test of the bar because the specimen slips through the jig grip. To prevent the rod from slipping, tensile tests were carried out with some filling conditions. The applicable and appropriate tensile test conditions were established by modifying the jig grip, treating the surface of the rod and using cryogenic epoxy infill to grip the rod. They were more than 1100 MPa. Additionally, the AFRP rod included a temperature dependence in which the Young's modulus increased as the test temperature decreased. It was confirmed that the Young's modulus increased because aramid fiber was more dominant than epoxy.
Hasegawa, Shoichi; Kato, Takashi; Aso, Tomokazu; Ushijima, Isamu*; Tatsumoto, Hideki; Otsu, Kiichi*; Ikeda, Yujiro
LA-UR-06-3904, Vol.2, p.402 - 407, 2006/06
In JSNS, the hydrogen of super critical state is adopted as moderators. Therefore the cryogenic hydrogen system is prepared, which consists of hydrogen circulating unit and transfer lines to moderators. The hydrogen system will immediately discharge hydrogen when an off-normal event occurs. In case of emergency, helium gas will be inputted to an insulation vacuum of the transfer line in order to enhance the heat transfer and the hydrogen discharge time should be shortened. Then, it is impotant to estimate the behaviour of pressure and velocity of discharging hydrogen in the emergency. During hydrogen discharge, the pressure rise in the discharge piping should be kept below the design pressure of 0.1 MPa. The result of analysis shows that the pressure of helium gas injection is suitable less than 0.04Mpa, and that the maximum hydrogen discharge flow is evaluated to be 0.047 kg/s after around 150 seconds. After five minutes with this condition, the hydrogen of around 90% in the moderator piping is discharged. Safety hydrogen release in the case of emergency can be established.
Tatsumoto, Hideki; Aso, Tomokazu; Hasegawa, Shoichi; Ushijima, Isamu*; Kato, Takashi; Otsu, Kiichi*; Ikeda, Yujiro
AIP Conference Proceedings 823, p.753 - 760, 2006/05
As one of the main experimental facilities in J-PARC, an intense spallation neutron source (JSNS) driven by proton beam power of 1 MW is constructed. In JSNS, cryogenic hydrogen at supercritical pressure is selected as a moderator. The total nuclear heating at the moderators is estimated to be 3.7 kW. A cryogenic hydrogen system to cool the moderators has been designed. As the most severe off-normal event for cryogenic hydrogen system, it is considered that the cryogenic hydrogen leaks when the pipe is cracked. In such a case, the hydrogen must be discharged safely as soon as possible. An analytical code that simulated the pressure change during hydrogen leak was developed. The pressure rise analysis for various sized cracks was performed, and then the required size of safety equipment was determined. It was found from the analysis that a safety valve of -42.7 mm and a rupture disk with the diameter of 37.1 mm can discharge hydrogen safely.
Aso, Tomokazu; Tatsumoto, Hideki; Hasegawa, Shoichi; Ushijima, Isamu*; Otsu, Kiichi*; Kato, Takashi; Ikeda, Yujiro
AIP Conference Proceedings 823, p.763 - 770, 2006/05
no abstracts in English
Tatsumoto, Hideki; Kato, Takashi; Aso, Tomokazu; Ushijima, Isamu*; Hasegawa, Shoichi; Otsu, Kiichi*
JAERI-Tech 2005-019, 16 Pages, 2005/03
JAERI-Tech-2005-019.pdf:1.29MB
As one of the main experimental facilities in J-PARC, an intense spallation neutron source (JSNS) is constructed. In JSNS, cryogenic hydrogen with temperature of 20 K and pressure of 0.5 to 1.5 MPa was selected as the moderator. The total nuclear heating at the moderators is estimated to be 3.7 kW for proton beam power of 1 MW. A cryogenic hydrogen circulation system, which plays a role in cooling spallation neutron and moderators, has been designed. For a certain operation condition, it is possible to occur boiling in the moderators. The boiling phenomenon would have an influence on the neutronic performance and the safety of the moderators. The heat transfer mechanism of cryogenic hydrogen in the moderators needs to be estimated. However, the mechanism has not been clarified until now. In this paper, the heat transfer of cryogenic hydrogen was estimated by using properties of cryogenic hydrogen and the heat transfer correlations used in other fluids, and then the operation condition of the cryogenic hydrogen system has been considered.
in irradiated solid 
-hydrogen and its decay dynamics; Reinvestigation of quartet electron paramagnetic resonance lines assigned to H
Kumada, Takayuki; Tachikawa, Hiroto*; Takayanagi, Toshiyuki*
Physical Chemistry Chemical Physics, 7(5), p.776 - 784, 2005/02
Times Cited Count：12 Percentile：38.35(Chemistry, Physical)The quartet ESR lines observed in X-ray irradiated solid parahydrogen, which have previously been assigned to H, are reinvestigated. We have reassigned the quartet lines to H rather than H. Based on the new assignment, previous data have been reinterpreted as follows. The H ion is composed of the collinearly aligned H core at the center and two H rotors at both ends. The ortho-para conversion of H core of H is completed within the time-scale of hours. H diffuses quantum mechanically by the repetition of H + H 
H + H reaction, and the diffusion terminates by the reaction with a HD impurity as H + HD H
D + H. Finally, we will propose a possible reason why H is produced instead of H
in the irradiated solid H.
Kumada, Takayuki
Physical Review B, 68(5), p.052301_1 - 052301_4, 2003/08
Times Cited Count：39 Percentile：81.49(Materials Science, Multidisciplinary)Effect of pressure on the recombination of H atoms produced by UV-photolysis of O-doped solid H was studied using ESR spectroscopy. The recombination rate constant was independent of pressure up to 13 MPa below 4.2 K, whereas it remarkably decreases with the increase in pressure above. The absence of pressure effect indicates that the H atoms do not diffuse by the physical exchange of positions with neighboring H molecules, but by the tunneling reaction H + H H + H.
Saito, Shigeru; Ouchi, Nobuo; Fukaya, Kiyoshi*; Ishiyama, Shintaro; Tsuchiya, Yoshinori; Nakajima, Hideo
JAERI-Tech 2003-027, 63 Pages, 2003/03
JAERI-Tech-2003-027.pdf:19.84MB
Around the super conducting (SC) coils of SC linear accelerator or fusion reactor, several kind of dissimilar materials bond will be needed. In recent years, pure titanium has been proposed as jacket material for SC coil of fusion reactor. Cu-alloys will be used for connection of SC coils. Cryogenic stainless steels have been development for structural material. Therefore, it is necessary to develop new bonding techniques and we started the bonding technology development by hot isostatic press (HIP) method to bond Cu-alloys with titanium and cryogenic stainless steels. In this experiments, optimization of HIP bonding condition and evaluation of bonding strength by metallurgical observation, tensile and bending tests were performed.
Saito, Shigeru; Ouchi, Nobuo; Ishiyama, Shintaro; Tsuchiya, Yoshinori*; Nakajima, Hideo; Fukaya, Kiyoshi*
JAERI-Tech 2002-048, 68 Pages, 2002/05
JAERI-Tech-2002-048.pdf:7.86MB
no abstracts in English
Kumada, Takayuki; Sakakibara, Masahiro*; Nagasaka, Toshimitsu*; Fukuta, Hiroya*; Kumagai, Jun*; Miyazaki, Tetsuo*
Journal of Chemical Physics, 116(3), p.1109 - 1119, 2002/01
Times Cited Count：44 Percentile：77.99(Chemistry, Physical)We have studied diffusion and recombination of H atoms in solid hydrogen using ESR, ENDOR, and ESE spectrometer. The rate constant for recombination of H atoms in highly purified parahydrogen was found to be much smaller than that expected by diffusion coefficient. This result indicates that the H atoms do not recombine in the absence of energy dispersion path in highly purified parahydrogen.
Hiratsuka, Hajime; Ichige, Hisashi; Kizu, Kaname; Iwahashi, Takaaki*; Honda, Masao; Kato, Atsushi*
JAERI-Tech 2001-019, 39 Pages, 2001/03
JAERI-Tech-2001-019.pdf:3.55MB
no abstracts in English
Kumada, Takayuki; Shevtsov, V.*; Aratono, Yasuyuki; Miyazaki, Tetsuro
Journal of Chemical Physics, 113(4), p.1605 - 1608, 2000/07
Times Cited Count：4 Percentile：12.24(Chemistry, Physical)no abstracts in English
Shevtsov, V.*; Kumada, Takayuki; Aratono, Yasuyuki; Miyazaki, Tetsuro
Chemical Physics Letters, 319(5-6), p.535 - 541, 2000/03
Times Cited Count：14 Percentile：40.89(Chemistry, Physical)no abstracts in English
; An Electron spin echo studyKumada, Takayuki; Noda, Tomoyoshi*; Kumagai, Jun*; Aratono, Yasuyuki; Miyazaki, Tetsuro
Journal of Chemical Physics, 111(24), p.10974 - 10978, 1999/12
Times Cited Count：10 Percentile：31.1(Chemistry, Physical)no abstracts in English
anions in solid parahydrogen via two-stage quantum tunneling diffusion processKumada, Takayuki; *; *; Kumagai, Jun*; Aratono, Yasuyuki; Miyazaki, Tetsuro*
Journal of Low Temperature Physics, 114(5-6), p.413 - 429, 1999/00
no abstracts in English
