Study on the Decay Law of γ Energy Spectrum of Radon and Its Daughters in Radon Chamber

Radon is one kind of radioactive gas which mainly distributed in soil and rocks, because of its strong upward migration ability, it is easy to diffuse into the air and cause radiation damage as the respiratory system enters the human body, which may cause lung cancer. Accurate measurement of concentration has always been a research area that has attracted much attention. There are various methods for measuring radon. Commonly used at home and abroad are thermoluminescence radon method, solid nuclear track radon method, activated carbon method, electret method, and scintillation chamber method. It is qualified for measurement under normal conditions, but in special applications such as the deduction of radon background in aerial gamma measurement, the above method is no longer applicable. At present, the detectors used in aviation gamma instruments at home and abroad are mainly large crystal sodium iodide detectors. The high-resolution array detector aviation gamma spectrometer developed by Ge Liangquan of Chengdu University of Technology also uses this kind of detection. In order to explore the effect of the detector on the direct measurement of the gamma energy spectrum of radon and its daughters. An experimental platform was built based on the HD-6 multifunctional automatic control radon chamber, the large crystal NaI(Tl) detector was used for measurement, and the HPGe detector was used for comparative measurement. Finally, the measurement results of the two were measured with the RAD7 radon meter. The obtained radon concentration was compared, and the reason for the abnormal data was studied. Through experiments, the large crystal NaI(Tl) detector can be applied to the direct measurement of the γ energy spectrum of radon and its daughters, and its practical effect is better than that of the electric cooling HPGe detector. The experiment found that the temperature is The count rate of the large crystal NaI(Tl) detector cannot be ignored, and temperature correction is required.