Results of the high-rate beam test of HypTPC at HIMAC

A time projection chamber (HypTPC) has been newly developed for the hadron physics experiments at J-PARC. The high rate secondary beam up to 10⁶ Hz from the world highest intensity proton beam has been taken into account in a design of the HypTPC. The triple GEM layers and the gating grid plane are adopted for the amplification of the HypTPC in order to suppress the ion backflow rate in the high rate beam condition. The General Electronics for Time Projection Chamber (GET) system is used for the data acquisition. The high rate beam test of the HypTPC up to 10⁶ Hz was done with the 230 MeV proton beam at HIMAC. The prescaled trigger rate was about 230 Hz with nearly 100% DAQ efficiency. The HypTPC was stably operated with low spark rate of a few times per minute even at the high rates and the triggered beam event was well separated with the help of the neighboring detectors. (author)