多球中子谱仪的周围剂量当量转换研究  

Research on the test, measurement and ambient dose equivalent conversion for a multisphere neutron spectrometer

作　　者：吕宁 过惠平 尚爱国 赵括 吕汶辉 肖琦展 孙铭言 杜泽群 孟瑞 陈俐文 王凯[3] 曹智 LYU Ning;GUO Huipin;SHANG Aiguo;ZHA0 Kuo;LYU Wenhui;XIAO Qizhan;SUN Mingyan;DU Zequn;MENG Rui;CHEN Liwen;WANG Kai;CAO Zhi(Rocket Force Engineering University,Xi'an 710025,China;Troops 92609 of PLA,Beijing 100077,China;Troops 96035 of PLA,Tonghua 134000,China;Troops 96871 of PLA,Baoji 721000,China;Troops 91515 of PLA,Sanya 572000,China)

机构地区：[1]火箭军工程大学,西安710025 [2]中国人民解放军92609部队,北京100077 [3]中国人民解放军96035部队,通化134000 [4]中国人民解放军96871部队,宝鸡721000 [5]中国人民解放军91515部队,三亚572000

出　　处：《核技术》2018年第12期51-58,共8页Nuclear Techniques

摘　　要：以辐射场全能段中子能谱获取及周围剂量当量转换为目的,针对一套以3He正比计数器为探测器的多球中子谱仪,介绍了采用脉冲幅度分析法进行中子-γ甄别,准确测量中子计数率的方法;测量并获取了实验室本底环境中子、Am-Be中子源、氘氘中子管连续出射中子三种辐射场的中子能谱,并予以分析;基于中子能谱进行周围剂量当量转换,分析了不同能量段中子所占的剂量比重,发现快中子是主要贡献者;在比较测量中,对三种单慢化体中子剂量仪器产生的误差进行了理论分析,并给出了依靠多球中子谱仪测准中子周围剂量当量的三点建议。多球中子谱仪可以直接测算周围剂量当量,可以指导其它中子剂量仪器的标校,还可以针对具体能量段进行中子防护设计,精准有效指导外照射剂量防护工作的开展。[Background] Neutron ambient dose equivalent is closely related to neutron energy. Acquisition of the energy spectrum is necessary to calculate the ambient dose equivalent accurately in the neutron radiation field.[Purpose] This study aims at the ambient dose equivalent calculation by shakedown test of multi sphere neutron spectrometer (MNS).[Methods] First of all, pulse height analysis (PHA) method was used for neutron/γ discrimination to precisely measure neutron count rate. Then the neutron energy spectrum was successfully obtained and carefully analyzed in three neutron radiation fields:laboratory background, Am-Be neutron source and DD tube emergency neutron. Neutron fluence was converted into ambient dose equivalent consulting the conversion coefficient recommended by International Commission on Radiological Protection (ICRP) report No.74, and dose contribution weight from neutron in different energy groups was analyzed. Finally, comparison test was made against three other instruments with mono moderator respectively, errors between MNS and them were analyzed theoretically.[Results] Neutron ambient dose equivalent converted from energy spectrum measured by MNS was consistent with the other three dose instruments. No matter what kind of the neutron radiation field is, fast neutrons are the main contributors to the dose.[Conclusion] PHA and pulse height spectrum monitoring is the critical point for neutron energy spectrum measurement. MNS can be used to measure and calculate neutron ambient dose equivalent directly, guide optimal reference radiation for other neutron dose instruments calibration, and radiation protection design against neutron of special energy groups.

关 键 词：多球中子谱仪 中子-Γ甄别 中子能谱 周围剂量当量 辐射场测量 剂量标校 

分 类 号：TL817[核科学技术—核技术及应用]