论文部分内容阅读
目的掌握LB6008型六路低本底α、β测量仪性能指标,准确测量样品中总α、总β放射性体积活度。方法使用239Pu、90Sr-90Y工作源和241Am、40K粉末源对仪器进行效率刻度,对本底计数率、串道比及效率稳定性进行分析,依据GB/T 11682—2008和厂家指标进行评价。结果α本底计数率≤0.07计数/(cm2·h),β本底计数率≤5.1计数/(cm2·h),各路α探测器2π探测效率比均>80%,β探测器2π探测效率比均>50%;241Amα源探测效率为(5.62±0.33)%,40Kβ源探测效率为(26.22±2.11)%,5 d内探测效率变化≤4.58%;α射线对β道的串道比≤1.6%,β射线对α道的串道比≤0.12%;本底月稳定性实际测量值均在N_b±3δ可接受范围内,95%的测量值在N_b±2δ目标值范围内。结论该测量仪的基本性能指标均达到国家规定的Ⅱ级标准,适于样品总放射性水平的常规测量。
OBJECTIVE To grasp the performance index of LB6008 six-way low background α, β measuring instrument and accurately measure the total α, β radioactive volume activity in the sample. Methods The instrument was calibrated by using 239Pu, 90Sr-90Y working sources and 241Am, 40K powder sources. The background count rate, cross-track ratio and efficiency stability were analyzed and evaluated according to GB / T 11682-2008 and manufacturer’s specifications. Results α background count rate ≤0.07 counts / (cm2 · h), β background count rate ≤5.1 counts / (cm2 · h), each α detector 2π detection efficiency ratio> 80%, β detector 2π detection The efficiency of detection for 241Amα source was (5.62 ± 0.33)%, that of 40Kβ source was (26.22 ± 2.11)%, and the detection efficiency was less than 4.58% within 5 days. The ratio of α ray to β channel ≤1.6%, and the ratio of β-ray to α-channel is less than or equal to 0.12%. The actual monthly stability of the month is within the acceptable range of N_b ± 3δ and 95% of the measured value is within the range of N_b ± 2δ. Conclusion The basic performance of the measuring instrument meet the national standard Ⅱ level, suitable for the routine measurement of the total radioactivity level of the sample.