In this paper,a method of radon measurement based on nitrogen scintillation in air was established.The real-time measurement of radon concentration in air is based on detecting the UV light from the deexcitation of excited Nitrogen,which was excited by α-particles.Aiming at the problems of low detection efficiency and vulnerability to noise interference caused by the extremely low yield of nitrogen scintillation light in the air,the experimental design was carried out by simulation optimization on the basis of 2-fold coincidence and threshold selection signals,and the feasibility of the scheme design was verified by experiments.Firstly,the simulation model of such a detector was established,considering the background from PMT dark noise and cosmic rays,threshold setting and 2-fold triggering logic were used and analysis was performed for noise reduction,and then detector size was optimized to achieve the highest detection efficiency by simulation.Finally,an experimental setup was built and the test results showed that there are an obvious linear relationship between the net counting rate of the detector and the radon concentration simultaneously measured by RAD7,suggesting the feasibility of radon measurement based on nitrogen scintillation in the air.After experimental fitting,the sensitivity of this detector is 0.010 27 cpm/(Bq/m3).This method can not only meet the needs of real-time online monitoring of radon concentration level in underground engineering fields such as mining industry and uranium exploration,but also provide a measurement method for real-time online measurement of air α aerosol without sampling.
关键词
α粒子/空气中氮气闪烁/氡探测器
Key words
α particle/nitrogen scintillation in air/radon detector
万方数据