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Iwamoto, Yosuke
no journal, ,
Radiation damage of materials in accelerator facilities is usually estimated with the average number of displaced atoms per atoms in a material, DPA. The accuracy of DPA values affect the facility design and the maintenance of operation. The radiation damage model in PHITS can treat the effects of secondary particles which include all particles created from the nuclear reactions with energies over about 20 MeV. The applicable energy range of this model is from eV to TeV. To spread PHITS to the design of the J-PARC neutrino experimental facilities, I calculated DPA values in carbon, beryllium, titanium under proton irradiation with GeV energy region and indicated that PHITS is available for radiation damage estimations in these facilities. I also found that DPA values of beryllium under 120 GeV proton irradiation calculated with PHITS give good agreements with those with MARS code which has been developed in Fermi National Accelerator Laboratory.
Saito, Shigeru; Okubo, Nariaki; Endo, Shinya; Suzuki, Kazuhiro; Hatakeyama, Yuichi; Kikuchi, Kenji*
no journal, ,
To evaluate the lifetime of the beam window of an accelerator-driven transmutation system (ADS) and spallation neutron source, material irradiation programs, the STIP (SINQ target irradiation program, SINQ; Swiss spallation neutron source) and MEGAPIE (MEGAwatt Pilot Experiment), have been executed. Part of the specimens were transported to JAEA and post irradiation examination (PIE) of the specimens was carried out. In this presentation, in addition to representative results of the PIE, our experience and knowledge of irradiation experiments and PIE processes will be introduced. These information will be useful for high energy particle irradiation experiments and PIE planed under the frame work of RaDIATE.
Takada, Hiroshi
no journal, ,
At the Japan Proton Accelerator Research Complex, a pulsed spallation neutron source provides neutrons with high-intensity and narrow pulse width to promote a variety field of materials science by injecting high power proton beam of 3-GeV, 1 MW at repetition rate of 25 Hz. The core components of the spallation neutron source are a mercury target, liquid hydrogen moderators and a reflector with beryllium and iron. Their sizes and arrangement were optimized to get superior neutronics performance for 100% para-hydrogen as the moderator material. Since the lifetime of the mercury target vessel made from SS316L steel is determined by the pitting damage induced by the pressure wave generated at the pulsed proton beam injection, mitigating the pitting damage is the most critical issue to achieve 1 MW operation for long time. So far, gas micro-bubbles injection technique and a target front structure to get faster mercury flow in narrow channel were employed for mitigating the pitting damage in the mercury target vessel. A pitting damage of 25 
m was observed on the target front after 670 MWh operation with an average power of 406 kW. In 2018, it is planned to observe the target front of the newly manufactured target after operation with a power of 300 to 500 kW. Further developments of the narrow channel structure of the target front will be carried out. It is also planned to make post irradiation examination to study radiation damage of the target vessel in other facility of Japan Atomic Energy Agency.