Basic performance of a position-sensitive tissue-equivalent proportional chamber (PS-TEPC)

The characteristics and performance of the prototype of a Position-Sensitive Tissue-Equivalent Proportional Chamber (PS-TEPC), consisting of a miniaturized micro-pixel chamber (μ-PIC), were investigated. The gas-gain curve of the μ-PIC and an approximate function with which to convert measured collected charge into the primary charge ionized by incident heavy-ion particles were obtained. The measured Linear Energy Transfer (LET) indicated good agreement with that of the injected beam calculated using SRIM2008 code in the LET range from 0.4 to 180keV/μm, which roughly covers the whole LET range required for space dosimeters. As expected, the measured energy resolution improved with increasing LET of the injected beam. It was estimated to be 27% for 0.4keV/μm, which is just about the LET of minimum-ionizing particles. Consequently, it was confirmed that the PS-TEPC exhibits no significant undesirable feature but is well suited for space dosimetry.