Influence of geometric factor on detection efficiency in low-background α/β radioactivity measurement
10.13491/j.issn.1004-714X.2024.02.013
- VernacularTitle:低本底α、β放射性测量中几何因子对探测效率的影响分析
- Author:
Xiaoshuang LI
1
;
Jiayu LIU
1
Author Information
1. Shanghai Insitution of Measurement and Testing Technology, Shanghai 201203 China.
- Publication Type:OriginalArticles
- Keywords:
α/β radioactivity;
Solid angle;
Geometric factor;
Detection efficiency;
Relative standard uncertainty
- From:
Chinese Journal of Radiological Health
2024;33(2):183-188
- CountryChina
- Language:Chinese
-
Abstract:
Objective To study the influence of the radius of the active zone of the plane source and the horizontal distance between the source center and the center of the detection window on the detection efficiency of low-background α/β measuring instruments. Methods The geometric factor was calculated under different conditions in MATLAB, and a traceable plane source was used to test and analyze two commonly used measuring instruments. Results With the other parameters unchanged, when the radius of the active zone R1 = 9 mm, the G value was greatest; and when the horizontal distance a = 0 mm, the G value was greatest. According to the calculation formula of the verification regulation, for the 90Sr-90Y planar source, at the maximum value of a, the detection efficiency of FYFS-400X was 1.2% lower, and that of MPC-9604 was 3.2% lower; for the 241Am planar source, the detection efficiency of MPC-9604 was 1.9% lower at the maximum value of a. Conclusion The geometric factor decreases with the increase in the radius of the active zone and the horizontal distance between the source center and the center of the detection window. At the central position, the geometric factor has less influence on the relative standard uncertainty of detection efficiency. When using a standard plane source for counting, measures should be taken to ensure that the plane source is always centrally located in the sample tray.
