考虑体积效应的液闪测氚计数条件优化研究(英文)
Optimization of Counting Conditions on Tritium Measurement in LSC Considering Volume Effect
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摘要: 采用外标转换谱指数(tSIE) 作为淬灭校正因子，通过研究闪烁液及样品总体积、闪烁液用量的影响获得液闪测氚时的最佳计数条件。结果表明，对于22 mL标准玻璃计数瓶，最佳计数体积为717 mL，体积过少或过多可导致高到10% 以上的测量误差，这主要是由液闪谱仪光电倍增管的面响应特性引起的。在获得的最佳计数体积基础上，对闪烁液的用量进行了研究。为了获得好的测量结果，闪烁液与样品的比例应高于2.4。另外，还通过实验研究了光照对测量结果的影响。在实验室条件下，实验室灯光及自然光所引起的本底辐射在样品静置2 h 后将不会对测量结果构成影响。The influence of sample volume and cocktail quantity on tritium measurement in liquid scintillation counter (LSC) was investigated experimentally in this paper to optimize the counting conditions. Results indicate that the optimal counting volume is between 7 mL and 17 mL using 22 mL glass vials, which should be mainly attributed to the sensitive character of photon multiplier tubes(PMTs) in LSC. With the obtained optimal volume, we also present the detailed procedure to determine the influence of cocktail quantity, which shows that the ratio of cocktail and sample water should be kept higher than 2.4 to obtain accurate results. In addition, experiments on the influence of light were also performed with pure cocktail and results indicate that 2 h is long enough to eliminate luminescence before counting.Abstract: The influence of sample volume and cocktail quantity on tritium measurement in liquid scintillation counter (LSC) was investigated experimentally in this paper to optimize the counting conditions. Results indicate that the optimal counting volume is between 7 mL and 17 mL using 22 mL glass vials, which should be mainly attributed to the sensitive character of photon multiplier tubes(PMTs) in LSC. With the obtained optimal volume, we also present the detailed procedure to determine the influence of cocktail quantity, which shows that the ratio of cocktail and sample water should be kept higher than 2.4 to obtain accurate results. In addition, experiments on the influence of light were also performed with pure cocktail and results indicate that 2 h is long enough to eliminate luminescence before counting.
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