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Morishita, Takatoshi; Kondo, Yasuhiro; Oguri, Hidetomo; Hasegawa, Kazuo; Tamura, Jun; Hirano, Koichiro; Ito, Takashi; Nammo, Kesao*; Sugimura, Takashi*; Naito, Fujio*
no journal, ,
The J-PARC accelerator comprises an injector linac, a 3 GeV Rapid-Cycling Synchrotron (RCS) and a Main Ring. Accelerator components in the linac contain a negative hydrogen ion source, a radio-frequency quadrupole (RFQ) linac, drift tube linacs (DTLs), separated-type DTLs, and annular-ring coupled structure (ACS) linacs. Beam commissioning started in November 2006 and beam delivery to users started in 2009. The ACS cavities were installed to increase the energy to the original design of 400 MeV. The new front end (ion source, RFQ, and chopping system) was installed in 2014 to increase the peak beam current from 30 to 50 mA. Currently, a peak current of 50-mA beam is delivered to the RCS with a beam pulse width of 0.27 ms for neutron and muon experiments and 0.1 ms for particle and nuclear experiments with the repetition of 25 Hz. The progress and the operating stability of the RF cavities and measures to maintain performance will be presented.
Morishita, Takatoshi
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Accelerators for Accelerator Driven Systems (ADS) are required to have extremely high operational stability to reduce the fluctuations in the thermal load for the subcritical reactor by beam trips. The J-PARC linac, which is also a high-intensity proton accelerator, has been focused on improving the operational stability of the accelerator to achieve both stable beam quality and high availability. Accelerator cavities in the J-PARC linac contain an RFQ, DTLs, SDTLs, and ACS. Beam commissioning started in November 2006 and beam delivery to users started in 2008. To contribute to the development of ADS accelerators, the operating status of RF accelerator cavities in recent years, especially the RF trips that causes a beam stop, and future improvement plans are presented in this workshop. Additionally, the beam stop event such as equipment failure and the details of preventive maintenance will be reported.