^(222)Rn/^(220)Rn子体连续测量仪采集α能谱的峰重叠因子研究

Experimental Study on the Peaks Overlap Factor in the Continuous Measurement of ^(222)Rn /^(220)Rn Progeny Gathering α Energy Spectrum

为配合222Rn/220Rn子体连续测量仪的研制,开展了用222Rn/220Rn子体测量仪采集α能谱的峰重叠因子研究。本研究以国家标准222Rn室与220Rn室分别作为纯222Rn子体与220Rn子体测量环境,用222Rn/220Rn子体连续测量仪采集222Rn子体与220Rn子体α能谱,求得各α能峰的重叠因子。研究结果表明:非真空条件下220Rn子体发射的8.78Me Vα粒子慢化到7.69Me Vα能谱峰计数区,以及222Rn子体发射的7.69Me Vα粒子慢化到6.00Me Vα能谱峰计数区的概率较大,可取0.0335、0.1791作为表征α能谱峰重叠情况的峰重叠因子θ1、θ2典型值。而8.78Me Vα粒子慢化到6.00Me Vα能谱峰计数区的概率非常小,其峰重叠因子θ3可以忽略;同一张滤膜重复多次使用并未导致峰重叠因子显著的变化,且不同滤膜的峰重叠因子的差异在2%以内,对测量仪测量误差的贡献有限。

In order to smoothly develop the αspectroscopy -based continuous measurement instrument of 222^ Rn/220^ Rn progeny, the reseach of peak overlap factor ofαspectroscopy achieved by the continuous measure-ment instrument was performed.The 222 ^Rn chamber（ national standard） , 220 ^Rn chamber were used as measure-ment environment of pure 222 ^Rn, 220 ^Rn progeny respectively, and the peaks overlap factors have been calculated byαenergy spectrums of 222 ^Rn（ or 222 ^Rn） progeny, which was gathered from the measurement environment by the continuous measurement instrument of 222 Rn/220 Rn progeny in the radon laboratory of university of south chi-na.The results showed that：Under the non vacuum condition, the probability of 8.78 MeVαparticle emitted by 220Rn progeny ThC′（212Po） slowing down to the 7.69 MeVαparticle counts region, and the 7.69 MeV al-pha particleemittedby 222Rn progeny RrC′（214^Po） slowing down to the 6.00 MeVαparticle counts region can not be ignored.But the probability of 8.78 MeVαparticle slowing down to the 6.00 MeVαparticle counts re-gion is very small;A membrane filter reuse don’ t result in peaks overlap factorsθ1 ,θ2 andθ3 significant chan-ges, and can take 0.0335, 0.1791 and zero as typical values respectively;The contribution to the instrument measurement error from membrane changing is limited, since the different membrane peaks overlap factor differ-ences within 2%.