GEM-TEPC电场模拟及增益分析方法研究

Simulation of Three Dimension Distribufion of Electric Field in GEM-TEPC and Methods to Study of its Effective Gain

为对现有组织等效正比计数器(TEPC)进行改进,使其满足高注量率辐射场测量,本实验室研制一套基于气体电子倍增技术(GEM)的宽量程TEPC。对GEM-TEPC来说,探测器的增益是其关键指标,施加在GEM电极上的电压、漂移区场强、收集区场强、灵敏区充入气体的成分、气压均影响探测器的有效增益。本工作通过ANSYS程序对GEM-TEPC的电场进行模拟计算,并对利用Garfield程序对其增益特性进行模拟的方法以及增益测量方法进行研究。

To optimize the design of tissue-equivalent proportional counter(TEPC) and make it satisfy the measurement of radiation field with high fluence rate, we set up a TEPC based on a Gas Electron Multiplier( GEM). The effective gain is very important for GEM-TEPC, and the key factors affecting the effective gain are the voltage of GEM electrode, the drift area field, collected area field, the gas components filling into sensitive area and the gas pressure. Three dimension distribufion of electric field in GEM-TEPC were simulated with code ANSYS, and the way how to simulate the maximum safe gain of GEM-TEPC with code Garfield and the way how to measure the maximum safe gain were studied.