Research On Fast Calibration Technology Of HPGe γ Spectrometer

The research of fast efficiency calibration technology based on Monte Carlo simulation method is of great significance in practical applications.It can both guide the implementation of nuclear emergency monitoring and improve relevant domestic standards.It can also be used as a supplement to the conventional efficiency calibration technology to guide the daily operation of the laboratory.So far,relevant standards and regulations related to the acquisition of γ-spectroscopy published at home and abroad have focused on the experimental aspect,but the use of experimental methods to calibrate the efficiency of the γ-spectrometer has not been able to meet the requirements of short-term and strong operability in nuclear emergency monitoring.The simulation method is simpler and faster than the experimental method to obtain the gamma energy spectrum.Therefore,it is necessary to use the monka simulation method to carry out rapid efficiency calibration research.Based on this status,the following work has been carried out:(1)For the common HPGe y spectrometer with a relative efficiency of 50%in the laboratory,four standard point sources of 137Cs,133Ba,60Co,and 152Eu are simulated on the axis of the detector and located at the front The detection efficiency of the five positions of 0mm,20mm,40mm,80mm,and 120mm was compared with the experimental efficiency after considering the coincidence correction.The detection efficiency of four standard body sources such as soil,aerosol,water,and vegetables at 0mm of the gamma spectrometer was also simulated,and compared with the experimental efficiency.(2)Based on the above results,for the same location,by analyzing the relationship between the volumetric source and point source simulation efficiency ratio and the experimental efficiency ratio,the theoretical value of experimental efficiency is calculated with the help of point source simulation efficiency,point source experiment efficiency,and body source simulation efficiency.And verify it.(3)Aiming at the standard types of HPGe γspectrometers in the laboratory(4 types of N and 5 types of P),standard volume sources prepared for different environmental media,simulate their detection efficiency at different heights of the y spectrometer,and obtain Fast efficiency calibration database.The conclusions are:proved the reliability of the method for detecting the efficiency of various point and body sources using the HPGe γspectrometer using monka simulation technology;the accuracy of the conversion factors for point and body source detection efficiency was verified;with the help of domestic nuclear facilities Various types of HPGe γ spectrometers that have been supervised by the regulatory unit have successfully verified the feasibility of a fast efficiency calibration database for y spectrometers.