原子能科学技术2024，Vol.58Issue(4)：922-928,7.DOI:10.7538/yzk.2023.youxian.0539
BNCT治疗束γ能谱仪的校准方法研究
Study on Calibration Method of γ Spectrometer for BNCT Treatment
张书峰 1石斌 1肖鸿飞 2陈军 1刘蕴韬 1张庆贤 2宋明哲1
作者信息
- 1. 中国原子能科学研究院,北京 102413
- 2. 成都理工大学,四川成都 610059
- 折叠
摘要
Abstract
Limited by the characteristics of the boron neutron capture therapy(BNCT)treatment beam,it is difficult to measure the γ ray energy spectrum of the source term.There are few relevant work has been carried out.Up to now,only the γ energy spec-trometer directly measured the source term γ rays,but the spectrometer was not been calibrated and unfold.In order to obtain an accurate γ energy spectrum of the source term,it is necessary to calibrate the γ energy spectrometer and establish the reliable response function of the system.This paper briefly introduces the γ energy spectrometer designed for BNCT treatment beam,and mainly introduces the calibration method suit-able for this spectrometer.The spectrometer consists of a high purity germanium(HPGe)detector and a shield system.Since the entire spectrometer is designed for high intensity neutron/γ mixed fields,the shield effect of the spectrometer is so effective,and it is impossible to calibrate the γ response of the entire spectrometer system through experimental methods.By analyzing the spectrometer system,the dead layer distribu-tion of the HPGe detector is the main influence factor,and other structures can be accurately obtained through X-ray radiography and geometric measurements.There-fore,the calibration method of the spectrometer is as follows:obtain an accurate model of the HPGe detector by X-ray radiography and calibration;use precision measure-ments,fine geometric measurement and material analysis to obtain an accurate model of the shield,and establish a calculation model of the spectrometer;acquire the response function of the spectrometer system through Monte Carlo N particle transport code(MCNP)calculation,and the energy spans from 0.1 MeV to 11 MeV with an energy interval of 10 keV.Among them,the HPGe detector dead layer distribution can be confirmed using the following steps.The efficiency of the HPGe detector was calibrated utilizing standard γ sources and high-energy γ reference radiation fields.The dead layer distribution of the HPGe detector was adjusted using MCNP to ensure agreement between calculated and measured efficiencies,thereby determining the geometric distri-bution of the dead layer.Therefore,using a combination of Monte Carlo simulation and experimental methods,the results can be traced to the corresponding national or nation-al defense standards,ensuring the accuracy and reliability of the key parameters of the spectrometer,and laying the foundation for subsequent spectrum unfold work.关键词
γ能谱仪/响应函数/HPGe探测器/MCNPKey words
γ energy spectrometer/response function/HPGe detector/MCNP分类
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张书峰,石斌,肖鸿飞,陈军,刘蕴韬,张庆贤,宋明哲..BNCT治疗束γ能谱仪的校准方法研究[J].原子能科学技术,2024,58(4):922-928,7.
