Study On The Reference Level Determination Method Of ²²²Rn/²²⁰Rn Progeny Measurement Based On ?? Spectrum

Different ²²²Rn/²²⁰Rn progeny reference level determination methods have different determination errors,which are related to the measurement method itself and its measurement procedure.The traditional ²²²Rn/²²⁰Rn progeny reference level determination method cannot directly obtain the counting information of each progeny,and it needs to measure the progeny concentration in multiple time periods,result in some errors cannot be avoided.In this paper,studying the measurement of ²²²Rn/²²⁰Rn progeny by??spectra,and establishing the theoretical model.In the pure ²²²Rn or ²²⁰Rn chamber,the measurement error of the??energy spectrum method is transmitted one direction by one along the decay chain,which improves the measurement accuracy of RaB and ThB.This is the main reason why the measurement error caused by this method is lower than other measurement methods.In the case of the ²²²Rn/²²⁰Rn mixed chamber,the error transmission direction is RaB?ThB?ThC?ThC?RaA?RaB?RaC,²²²Rn/²²⁰Rn progeny will interfere with each other,which is caused by the inability of energy spectrum to completely distinguish interference peaks.In this paper,the efficiency calibration of the HPGe detector for the circular sampling filter film source was completed,and the simulation error of the RaB characteristic energy could be controlled within 3%.However,the detection efficiency of the measured value of the characteristic energy released by the RaC was lower than the simulation value,which may be caused by the inaccurate control of the dead layer and the size of the cold finger of the HPGe probe in the simulation process.In order to facilitate the processing of²²²Rn/²²⁰Rn progeny measurement data,this paper also built“²²²Rn/²²⁰Rn progeny measurement data processing software”to realize automatic,fast and accurate processing of measurement data.??spectra are expected to be developed as a new reference level determination method for ²²²Rn/²²⁰Rn subsets,with lower error lower limit.Compared with the ²²²Rn/²²⁰Rn mixed environment,pure ²²²Rn or pure ²²⁰Rn chamber is more suitable for calibration of the ²²²Rn/²²⁰Rn progeny measurement instrument.It can also be used for environmental measurement,which can improve the measurement accuracy of daughter body and further improve the dose evaluation level of ²²²Rn/²²⁰Rn daughter body in the environment.