Design and application of a large-volume sample cassette for nuclear radiation emergency monitoring
10.13491/j.issn.1004-714X.2024.04.002
- VernacularTitle:核辐射应急监测大体积样品盒的设计及其应用
- Author:
Lingnan KONG
1
;
Baolu YANG
1
;
Jing ZHANG
1
;
Qiang ZHOU
1
Author Information
1. Key Laboratory of Radiological Protection and Nuclear Emergency, China CDC, National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention, Beijing 100088 China.
- Publication Type:OriginalArticles
- Keywords:
Detection limit;
Large-volume sample cassette;
Sourceless efficiency calibration;
Detection time
- From:
Chinese Journal of Radiological Health
2024;33(4):358-363
- CountryChina
- Language:Chinese
-
Abstract:
Objective To develop a large-volume sample cassette in the shape of a formalin cup suitable for portable HPGe γ spectrometer, to determine the detection limits of the cassette at different detection times through fresh sample measurements, and to provide a reference for responding to and monitoring of nuclear and radiation emergencies. Methods According to the formula for calculation of detection limit described in the GB/T 16145—2022, 131I and 137Cs were measured using the sourceless efficiency calibration software Angle and the portable HPGe γ spectrometer for the optimization of the large-volume sample cassette. Fresh salmon samples were measured using a formalin cup-shaped large-volume sample cassette. The detection times were 2, 4, 6, 8, 10, 19, 19, 22, and 24 hours. The relationship between detection time and detection limit was assessed. Results Using sample cassettes with 15 cm radius and 10 L volume, the simulated detection efficiency of the formalin cup-shaped large-volume sample cassette was 30%-46% higher and the detection limit was lower as compared with the cake-shaped large-volume sample cassette. The detection limit obtained by measuring fresh salmon samples decreased with the extension of the detection time. These results provided a reference for the detection limits of measuring fresh samples for nuclides of concern in nuclear contaminated water with different detection times. Conclusion The formalin cup-shaped large-volume sample cassette developed by combining the optimization of detection limit provides a geometry for quantitative analysis in on-site monitoring of γ nuclides in the case of emergencies. Measurement of fresh samples using the cassette with different detection times showed that 8-10 hours of detection was optimal in balancing the detection limit and the detection time.
