闪烁体低本底α/β测量仪在饮用水总α与总β测定时的串道修正  

Crosstalk correction for determination of gross alpha and beta radioactivities in drinking water using a low background scintillation counter

作　　者：欧频[1] 郑雪婷 谭敏瑜 黄丽芳 李昱丞 OU Pin;ZHENG Xueting;TAN Minyu;HUANG Lifang;LI Yucheng(Huizhou Hospital for Occupational Disease Prevention and Treatment,Huizhou 516008,China)

机构地区：[1]惠州市职业病防治院,惠州516008

出　　处：《核技术》2021年第9期32-38,共7页Nuclear Techniques

基　　金：2019年度惠州市科技计划项目(No.2019Y138)资助。

摘　　要：闪烁体低本底α/β测量仪存在α-β串道现象。为了减少α-β串道对饮用水总α、总β放射性测定的影响,在确定引起串道的粒子或射线、串道修正因子与标准源面积及厚度的关系的基础上,对饮用水总α、总β放射性测定结果进行α-β串道修正及验证。结果显示:α粒子在β道引起串道,β粒子、X-γ射线在α道不引起串道。α标准源的α-to-β串道修正因子随源的厚度增加先增大后趋于稳定,且与源的面积无关;β标准源的β-to-α串道修正因子为零。经α-to-β串道修正后的总β放射性结果更接近真实水平,总α放射性测定不受β粒子串道影响。合理提高α阈可消除β粒子及X-γ射线在α道串道,合理设置β上、下阈使α标准源的α-to-β串道修正因子尽可能地小,并对β计数进行α-to-β串道修正可有效减少α粒子串道对总β放射性测定的影响。[Background]There is α-β crosstalk in determination of gross α and β radioactivities in drinking water using a low background scintillation counter,which may lead to erroneous measurement results.[Purpose]This study aims to reduce the α-β crosstalk in the determination of gross α and β radioactivities on a low background scintillation counter.[Methods]First of all,α-β crosstalk correction factors for α(241Am)and β(90Sr-90Y)planar sources were determined on a typical scintillator with low background α/β measuring instrument--BH1227,to ascertain the particles or rays causing the α-β crosstalk.Then,α-β crosstalk correction factors for α and β standard sources with different areas and thicknesses were measured by the BH1227 to explore the relationship between the crosstalk correction factors and the areas and thicknesses of α and β standard sources.The gross α and β radioactivities of drinking water samples with different α or β radioactivity levels were measured and corrected by the BH1227,and the crosstalk correction factors obtained from the α and β standard sources,respectively.Finally,comparisons of the gross α and β radioactivities without and with the crosstalk corrections in drinking water samples were performed to verify the crosstalk correction.[Results]It is shown that,while pulses arising from alpha particles can get into β channel,the opposite is not typically done.With the increasing of thicknesses of theαstandard sources,the α-to-β crosstalk correction factors increase first and then tend to be stable,but have no relation with their areas.The β-toαcrosstalk correction factor for theβstandard sources is zero.The correction with the α-to β crosstalk correction factors obtained fromαstandard sources,which have the same thickness and area as sample sources,minimizes theα-to-β crosstalk in gross β radioactivity measurement for drinking water samples.The determination of grossαradioactivity in the drinking water samples is not affected by the β-to-αcrosstalk.[Con

关 键 词：闪烁体低本底 α/β 测量仪 饮用水总 α、总β 放射性测定 串道修正 

分 类 号：TL812.1[核科学技术—核技术及应用]