Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China
Plenty of experimental studies on the effects of performances of RPC operated with different gas mixtures have beer. carried out. The curves of signal amplitude, multi-counting, efficiency, single counting rate and dark current versus the high voltage were measured using cosmic rays, based on the gas mixtures of Argon, Iso-butane and F134A with different fractions. The measured results show the plateau length could be prolonged, the detection efficiency increased and the dark current decreased in the plateau region of RPC, if the Argon ratio was reduced and the ratios of Iso-butane and F134A increased correspondingly, at the cost of increasing the working high voltage.