Interlock system of beam line for beam current upgrade

Kawane, Yusuke*; Miura, Akihiko ; Miyao, Tomoaki*; Hirano, Koichiro  ; Sugimura, Takashi*; Kato, Yuko; Sawabe, Yuki; Fukuda, Shimpei; Ouchi, Nobuo 

In the J-PARC Linac, because an upgrading of a beam current up to 50mA using an RF-driven ion source and a new RFQ Linac cavity is in progress, we have developed a new frontend equipments. In order to protect the scraper against 50 mA, we need to observe the temperature and to avoid the excess heat loading of the scraper surface and to count the irradiated beam particles. We also monitor the beam transmission between the upstream and downstream of the chopper cavity to check the chopping errors using the beam current monitors. We fabricated the interlock system for the temperature, irradiated particle numbers and beam transmission. And we tested them in the test stand with actual beam. This paper describes the interlock system and their test results.