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Takada, Hiroshi; Naoe, Takashi; Kai, Tetsuya; Kogawa, Hiroyuki; Haga, Katsuhiro
Proceedings of 12th International Topical Meeting on Nuclear Applications of Accelerators (AccApp '15), p.297 - 304, 2016/00
In J-PARC, we have continuously been making efforts to operate a mercury target of a pulsed spallation neutron source with rated power of 1-MW. One of technical progresses is to mitigate cavitation damages at the target vessel front induced by the 3-GeV proton beam injection at 25 Hz. We have improved the performance of a gas micro-bubbles injection into the mercury target, resulting that no significant cavitation damages was observed on the inner surface of target vessel after operation for 2050 MWh with the 300-kW proton beam. Another progress is to suppress the release of gaseous radioactive isotopes, especially tritium, during the target vessel replacement. We have introduced a procedure to evacuate the target system by an off-gas processing apparatus when it is opened during the replacement operation, achieving to suppress the tritium release through the stack. For example, the amount of released tritium was 12.5 GBq, only 5.4% of the estimated amount, after the 2050 MWh operation. After these progresses, the operating beam power for the pulsed spallation neutron source was ramped up to 500-kW in April, 2015.
Oi, Motoki; Meigo, Shinichiro; Akutsu, Atsushi*; Kawasaki, Tomoyuki; Nishikawa, Masaaki*; Fukuda, Shimpei
Proceedings of 12th International Topical Meeting on Nuclear Applications of Accelerators (AccApp '15), p.89 - 96, 2016/00
At J-PARC, 3 GeV proton beam with power of 1MW is delivered to the spallation neutron source (JSNS) through beam transport line called 3NBT. At the high power accelerator facilities even a small abnormal event has a possibility to be critical so that the beam control system is crucial. In order to find tiny anomaly, rapid data analysis system is required. We developed control and data analysis system based on the Experimental Physics and Industrial Control System (EPICS) and Control System Studio (CSS). To carry out beam tuning efficiently, the beam control system based on the Strategic Accelerator Design (SAD) code has been developed. With the several shots of beam and by the one click of operational panel of the screen, required magnet field can be calculated and set automatically. Also we developed automated e-mail system to announce the abnormal event to the experts persons. With these systems, we can reduce both beam tuning time and down time.
Meigo, Shinichiro; Oi, Motoki; Ikezaki, Kiyomi*; Kawasaki, Tomoyuki; Kinoshita, Hidetaka; Akutsu, Atsushi*; Nishikawa, Masaaki*; Fukuda, Shimpei
Proceedings of 12th International Topical Meeting on Nuclear Applications of Accelerators (AccApp '15), p.255 - 260, 2016/00