不锈钢和钨材料对东方超环(EAST)装置硬X射线诊断系统的影响

Effects of stainless steel and tungsten on a hard X-ray diagnostics system in the Experimental Advanced Superconducting Tokamak(EAST)

计算了不锈钢、铅和钨材料对不同能量硬X射线的衰减规律,根据计算结果设计了东方超环(EAST)超导托卡马克硬X射线诊断系统探测器的屏蔽准直体;详细介绍了EAST上硬X射线诊断系统,利用^(22)Na放射源对诊断系统进行了台面实验测试,通过放射源的γ射线能谱研究了不锈钢和钨材料对γ射线的衰减规律,拟合计算了衰减系数;同时将实验结果和理论计算结果进行了比较,考虑到实验误差的影响,实验结果和理论计算结果是一致的。通过研究γ射线能谱,对不锈钢和钨材料对X射线、γ射线诊断产生的影响进行了评估。研究结果发现:不锈钢对低能的X射线和γ射线诊断的影响比较严重,而对高能硬X射线以及高能γ射线诊断的影响在一定程度上是可以忽略的,但是要避免探测器的准直孔前方有钨和铅等高Z材料,以减小对诊断数据的影响。

Attenuation coefficients ofγ-rays in stainless steel,lead,and tungsten were calculated theoretically.According to the theoretical calculations,cylindrical lead shielding and a collimator were designed for a high-energy hard X-ray spectrum diagnostic system in the Experimental Advanced Superconducting Tokamak(EAST).The hard X-ray diagnostic system of EAST was introduced in detail,and the diagnostic system was tested through table experiments with radioactive^(22)Na sources.Attenuation coefficients ofγrays in stainless steel and tungsten were also obtained by fittingγ-ray radiation spectra.The effect of the stainless steel and tungsten materials on the X-ray andγ-ray diagnostic system was evaluated byγ-ray energy spectra.The attenuation coefficients obtained through the experiments were found to agree well with those calculated theoretically considering the error.The influence of stainless steel on low-energy X-ray orγ-ray diagnostics cannot be ignored,while its influence on high-energy X-ray orγ-ray diagnostics can be ignored.The influence of tungsten on X-ray orγ-ray diagnostics cannot be ignored.However,high Z materials such as tungsten and lead should be avoided in front of the collimation hole of the detector to reduce the influence on diagnostic data.