G-M计数器用于n、γ混合辐射场γ周围剂量当量测量研究

The Study on the Measurement of the Ambient Dose Equivalent of Gamma Radiation in n,γMixed Radiation Fields Using a G-M Counter

基于中子的产生和反应机制,中子参考辐射场均为n、γ混合场,其γ成分主要来源于中子产生时的伴随γ和中子与辐射场环境物质相互作用产生的γ。本工作研究了一种能量补偿型盖革-弥勒(G-M)计数器在n、γ混合辐射场中的应用。通过蒙特卡罗(MC)粒子输运程序MCNP对其能量响应进行模拟研究,并在γ参考辐射场中进行实验验证,验证了其能量补偿方案能够有效抑制低能区的过响应。利用该能量补偿型G-M计数器对实验室放射性核素中子源辐射场的γ周围剂量当量进行测量,完善了参考辐射场的参数,可为解决由中子仪表的γ响应特性带来的校准问题提供支撑。

Based on the mechanisms of neutron production and reactions,neutron reference radiation fields are n,γmixed fields,where the gamma component primarily originates from gamma rays accompanying neutron production and those generated by the interaction of neutrons with materials in the radiation field environment.This paper investigates the application of an energy-compensated Geiger-Müller(G-M)counter in n,γmixed radiation fields.Using the Monte Carlo(MC)particle transport code MCNP,the energy response of the G-M counter was simulated,and experimental validation was conducted in a gamma reference radiation field.The validation demonstrated that the energy compensation scheme effectively suppresses the over-response in the low-energy region.Utilizing this energy-compensated G-M counter,the ambient dose equivalent of gamma radiation in laboratory radioactive nuclide neutron source fields was measured.This improves the parameters of the reference radiation field and provides support for addressing calibration issues arising from the gamma response characteristics of neutron instruments.