超低本底流气式正比计数器在样品总α/β测量中串道影响修正

Correction of crosstalk influence in the sample measurement of total α/βused by ultra low background flow gas proportional counter

超低本底流气式正比计数器是样品总α/β测量的理想探测器,但本身具有较强的串道现象,影响样品测量的准确性。系统研究了流气式正比计数器在同一质量厚度、不同241 Am和40 K质量分数下α→β、β→α串道影响,建立了总α/β串道修正的二元方程,并与遮盖修正法进行对比,对自制的25组α/β模拟粉末样品进行了测量和串道修正。结果显示α→β串道影响较大,修正因子随着α计数率的变化并非恒定值;β→α串道修正因子影响较小,其平均值为0.001;遮盖修正法对模拟粉末样品中β测量结果的修正效果较差,其相对偏差绝对值介于1.4%~45.0%;二元方程修正法对模拟粉末样品中β测量结果的修正效果较好,其相对偏差绝对值介于0~5.5%。

The ultra-low background flow gas proportional counter is the ideal detector for totalα/βsample measurement,but itself has strong crosstalk phenomenon,which affects the accuracy of sample measurement.This paper systematically studies the flow type proportional counter under the same mass thickness,different 241 Am and 40 K mass fractionsα→β,β→αCross channel influence.This paper established a binary equation for totalα/βchannel correction and compared it with the cover correction method and with the self-made 25 groupsα/βsimulate powder samples for measurement and channel correction.The results show that:The impact ofα→βcrosstalk is significant;The change withαcounting rate is not constant;The influence of theβ→αchannel correction factor is relatively small,with an average value of 0.001.The accuracy of the measurement results is poor by using the cover correction method to correct the simulated powderβsample,with absolute relative deviation ranging from 1.4%to 45.0%.The binary equation correction method is used to correct the simulated powderβsample.The accuracy of the measurement results is relatively high,with an absolute value of relative deviation ranging from 0 to 5.5%.