Simulation of photoelectric X-ray polarimetry and reconstruction of the photoelectron azimuthal angle  

作　　者：王烁 季建峰 韩冬 冯骅 

机构地区：[1]Department of Engineering Physics,Tsinghua University [2]Key Laboratory of Particle and Radiation Imaging (Tsinghua University),Ministry of Education

出　　处：《Chinese Physics C》2013年第3期69-73,共5页中国物理C（英文版）

基　　金：Supported by NSFC(10903004,10978001);973 Program (2009CB824800)

摘　　要：Sensitive X-ray polarimetry in the keV energy range can be achieved by measuring the azimuthal angle distribution of emitted electrons after the photoelectric absorption of X-rays in a micropattern gas detector. However, the initial direction of the electron is not readily measurable due to the randomization of its motion during energy loss. By using the Geant4, Maxwell and Garfield packages, we simulated the detected electron tracks following photoelectric absorption, electron drift and diffusion in the gas, and proposed a technique capable of reconstructing the initial direction of the emitted photoelectron. The technique allows us to measure the angular modulation of flux predicted for a polarized X-ray beam. We calculated the modulation factors in 2-10 keV with a gas mixture of neon and CO;, and discussed how electron diffusion along the drift will dilute the track and suppress the modulation. These results are useful for the design of the X-ray polarimeter.Sensitive X-ray polarimetry in the keV energy range can be achieved by measuring the azimuthal angle distribution of emitted electrons after the photoelectric absorption of X-rays in a micropattern gas detector. However, the initial direction of the electron is not readily measurable due to the randomization of its motion during energy loss. By using the Geant4, Maxwell and Garfield packages, we simulated the detected electron tracks following photoelectric absorption, electron drift and diffusion in the gas, and proposed a technique capable of reconstructing the initial direction of the emitted photoelectron. The technique allows us to measure the angular modulation of flux predicted for a polarized X-ray beam. We calculated the modulation factors in 2-10 keV with a gas mixture of neon and CO_2 , and discussed how electron diffusion along the drift will dilute the track and suppress the modulation. These results are useful for the design of the X-ray polarimeter.

关 键 词：X-RAY POLARIMETRY micropattern gas detector 

分 类 号：O434.1[机械工程—光学工程]