【作者】 张学粮； 张化一；

【Author】 Zhang Xueliang Zhang Huayi (Key Laboratory of Particle & Radiation Imaging,Ministry of Education,Tsinghua University,Beijing 100084)

【机构】 清华大学工程物理系粒子技术与辐射成像教育部重点实验室；

【摘要】 电子加速器作为一种常用的辐射源,其能量规定为必检项目。本文提出了一种能够在线快速测量电子束能量的新方法,通过比较两块导体板上的沉积电荷量以获得电子束的能量信息。本文围绕这一方法展开模拟和实验研究,先采用通用蒙特卡罗方法MCNP程序建立了单双板模型进行模拟,结果表明平衡厚度对能量较为敏感,两者之间存在较为良好的线性关系;设计并加工了相应的能量测量装置,并在6MeV电子束下进行了实验,实验结果所反映的趋势与模拟结果较为一致,材料对平衡厚度的影响也与模拟吻合。但由于二次电子的影响,实测平衡厚度与模拟存在较大偏差,改进装置将会很好地抑制二次电子的影响,使得实测结果更接近模拟结果。更多还原

【Abstract】 As an often-used radiation source,the energy of electron accelerator is stipulated as an item that must be verified and displayed.This article put forward a new method that can be used to measure the eletron beam energy online,namely by comparing the number of charges deposited separately in two parallel conductors.Simulation and experimental research were carried on this method.The simulation work was done by establishing single and double models in MCNP,common used Monte Carlo Method software.The result shows that the balance-thickness is sensitive to beam energy,and indicates the good linear relationship between balance-thickness and beam energy.An energy measure device was designed and manufactured.Experiments using the device were carried on under a 6MeV electron beam.The experimental results shows the same trends as simulation results,including normalized electron number vs the thickness of upper plate,the affection to balance-thickness caused by material of lower plate.As a result of affections caused by secondary electrons,the measured balance-thickness has large error comparing to the simulated balance-thickness.Affections of secondary electrons may be well restrained by improving the existing device so that the experimental results much closer to simulation ones can be gained.More work on this method is ongoing.更多还原