13th Vienna Conference on Instrumentation - VCI2013

Development of PS-TEPC (Position Sensitive Tissue Equivalent Proportional Chamber

Not scheduled

50m

Vienna University of Technology

Board: 46

Poster Medical Applications

Speaker

Dr Yuji Kishimoto (High Energy Accelerator Research Organization)

Description

Radiation effects on human body are evaluated using dose equivalent H, defined as a product of an absorbed dose D and a quality factor Q given as a function of LET. In space, there exist many kinds of cosmic radiations, where primary charged particles and neutrons generated secondarily are the main components contributing to radiation dose. Since LET of these radiations widely distributes, it is essential to measure directly LET to evaluate H. A Tissue Equivalent Proportional Counter (TEPC) has been used as a standard space dosimeter. In TEPC, however, no position information is given and LET is assumed to be equal to a lineal energy y (the deposited energy divided by mean chord length of detector) for a real time dose measurement. Obviously, y does not represent LET accurately, and H obtained with TEPC is reported to be more than twice that measured with the other real LET spectrometer. We have been developing a new space dosimeter named as PS-TEPC, which is based on a time projection chamber (TPC) using a micro-pixel chamber (μ-PIC) as a 2-demetional readout device. We constructed a small TPC with tissue-equivalent materials, and demonstrated successfully the feasibility from the results of 3D-tracking and the energy measurements performed for heavy ion beams. Experiments using PS-TEPC are scheduled to start from 2014-2015 in the International Space Station. We are trying to complete a prototype of PS-TEPC usable in space. The present status of PS-TEPC will be given.