摘要
对真空康普顿探测器灵敏度构成进行了分析,得到了影响探测器能量响应的关键因素。使用蒙特卡罗方法对比分析了这些关键因素对探测器能量响应平坦性的影响。结果表明:发射极的材料及厚度是决定能量响应的最重要因素,不同材料、不同厚度的发射极,探测器能量响应曲线差异较大,对于高Z材料,厚度10μm量级与100μm量级,探测器能量响应曲线有着相反的变化趋势;前窗是影响探测器能量响应的次重要因素,前窗材料的种类对能量响应影响的分散性小于10%,而前窗材料厚度对探测器能量响应影响较大;后窗对能量响应影响的分散性小于5%;衰减物质使探测器对低能(<0.4 MeV)γ射线的灵敏度衰减较大,主要用来调整探测器对低能γ射线响应曲线的变化趋势。
Based on analyzing the constituents of quantum efficiency of vacuum Compton detectors(VCDs),we found the key factors that would affect the energy response of VCDs.We investigated the influences of these factors with MCNP and got the following results:1)The material of the emitter and its thickness are vital factors affecting the energy response,and the energy response curve would differ greatly for different materials and thickness.For the materials of larger Z,the emitter of tens micrometers thick has an energy response curve reverse to that of emitter of hundreds micrometers;2)The front window is also an important factor.The changes of front window thickness will cause more variations in energy response comparing with the changes of the materials,which causes a dispersity in energy response less than 10%;3)The rear window is less influential,impacting less than 5% dispersity on the energy response.4)Attenuation sheet before the VCDs is more effective for gamma-rays of low energy,probably less than 0.4MeV,and can be used to adjust the energy response to gamma-rays with relatively low energy.
出处
《现代应用物理》
2015年第1期20-26,共7页
Modern Applied Physics
基金
国家自然科学基金资助项目(11375145)