【作者】 何丽娟； 陈志； 吴璨； 於国兵； 顾先宝； 杜勤； 李为民；

【机构】 安徽省合肥市中国科学技术大学国家同步辐射实验室； 安徽省辐射环境监督站；

【摘要】 国家同步辐射实验室200MeV电子直线加速器是我国最早的高能电子加速器之一。电子从电子枪打出后在五段加速管中逐级加速到200MeV左右,电子在加速过程中会因轰击结构材料(尤其是刮束器)而有所损失。损失的电子由于发生轫致辐射、级联簇射以及光核反应,将会产生大量的感生放射性。通过累积剂量的测量发现:直线加速器在开机状态下,电子主要损失在刮束器结构处,加速段能量为116MeV处尤为明显。通过使用HPGe谱仪对停机状态的直线加速器32MeV和158MeV加速能量段处刮束器的γ能谱现场测量实验发现:不同加速段结构材料中生成的感生放射性活度与该段加速电子的能量存在着一定的关系。目前,该直线加速器将因升级改造而退役,为深入研究结构材料中的感生放射性提供了可能。感生放射性的深入研究将可以为今后同类加速器的退役和结构材料的后处理提供理论依据,同时也可为该加速器升级改造在结构设计和材料选取,辐射防护方案的制定以及束流损失监测方面提供有价值的参考。更多还原

【Abstract】 The 200 MeV Electron Linac of National Synchrotron Radiation Laboratory(NSRL Linac) is one of the earliest high-energy electron linear accelerators in China.The electrons in it are gradually accelerated to about 200 MeV from low energy by five accelerating tubes.During the accelerating period,the lost electrons will hit on the accelerator structure materials(especially scraper structure material).Therefore,much induced radioactivity will be produced due to bremsstrahlung,cascade shower and photo-nuclear reaction.The measurements of the dose show that:in the booting state,most of electrons loss in scraper structure material,especially for 116 MeV.The measurements of y spectrum at the scraper of 32 MeV and158MeV show that:there are some relationships between the proportions of different nuclides induced radioactivity generated in different acceleration tube structural materials and the accelerated electron energy in the corresponding section.At present,the linac will be retired because of upgrading.The equipment and materials removed can be used to study induced radioactivity generated in different acceleration tube structural materials.The research will provide the theoretical basis for the similar accelerator decommissioning,and offer the significant reference for structure design,material selection and radiation protection programs design as well.更多还原