基于同步辐射的硬X射线探测器标定方法及关键技术研究

项目名称： 基于同步辐射的硬X射线探测器标定方法及关键技术研究

项目编号： No.11375227

项目类型： 面上项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 赵屹东

作者单位： 中国科学院高能物理研究所

项目金额： 105万元

中文摘要： 本项目旨在基于国内现有同步辐射光源，研究高通量密度条件下硬X射线探测器标定方法及关键技术。研究内容包括（1）通过Monte-Carlo 模拟高通量密度X射线入射下气体中的电离情况，研究复合损失与电离室灵敏区电场、气体配比和压力的相关性，通过系统地实验研究给出探测器气体配比、压力及收集电场等参数设置，设计并研制出适合同步辐射高通量密度条件下工作的在线实时监测探测器。（2）建立以自由空气电离室为基础的离线实验室参考标准，通过传递探测器对在线实时监测探测器进行校准，考核校准系统的稳定性，并分析影响整个系统测量不确定度的因素。（3）建立同步辐射硬X射线标定系统及光子通量绝对测量的实验室标准，其能量范围6keV-20keV，可测最高光子通量超过1E10 phon/s ，整体不确定度优于2%。为激光等离子体诊断、天文观测以及其它交叉学科领域的相关应用提供X射线绝对量值溯源基础。

中文关键词： 硬X射线;探测器标定;电离室;同步辐射;

英文摘要： In metrology, the radiation detector standards are divided into primary standards and secondary, or transfer standards. As we all know,free-air ionization chambers are widely used as primary standards for the absolute measurement of air kerma in X-ray fields. However, they suffer ion-recombination seriously at the high dose rate, such as for synchrotron radiation beamlines. We propose a comprehensive study on hard X-ray decters calibration under high-flux density synchrotron radiation source with both a free-air ionization chamber and a flow-gas ionization chamber. A research will be done on the subject of the relationship beween recombination loss and electric field,gas composition and pressure,and also photon flux density by Monte-Carlo simulation as well as experiment.For the determination of absolute photon flux from high-intense synchrotron radiation beamline, a new detector system based on the photon-ionization of rare gases will be developed as an online monitor. A free air ionization chamber will be designed as primary standard to calibrite the online monitor with a semiconductor photodiode as a transfer standard. This study will provide fundamental experimental data and quantitative uncertainty analysis for establishment of a dector calibration system in the energy range of 6keV to 20keV,with the highest measurable photon flux over than 1E10 phon/s and the uncertainty better than 2%. We belive that this project must be able to provide more accuracy evaluation in the field of laser plasma, astronomical observation and other interdisciplinary application of traceability.

英文关键词： Hard X-ray;Detector Calibration;Ionization Chamber;Synchrotron Radiation