便携式食品放射性检测仪的研制及测试

设计了一种便携式食品放射性检测仪，主要包括测量结构、核信号处理单元和能谱分析程序。核信号处理单元主要包括抗混叠低通滤波器、程控增益放大器、高速A/D采样、数字低通滤波、梯形成形、脉冲幅度甄别和能谱获取等。能谱分析程序主要包括能谱光滑、能谱寻峰、能量刻度、本底扣除以及活度计算等。最后，以测量131I核素为例，研究了仪器对不同体积样品的探测效率、刻度系数和最低可探测活度，并根据刻度系数对300 mL食品样品的放射性测量结果进行校正。结果表明，仪器对常见食品中131I的放射性活度检测结果误差小于10%，满足食品放射性测量需求。

The Development and Test of a Portable Food Radioactivity Monitor

A portable food radiation monitor has been developed and tested. This paper introduced the measurement structure, nuclear signal processing unit and the analysis application program. The nuclear signal processing unit includes anti-aliasing low-pass filter, programmable gain amplifier, high-speed A/D sampling, digital low-pass filter, trapezoidal shaping, pulse amplitude discrimination, and energy spectrum acquisition unit. The analysis application program includes functions for spectral line smooth, spectral peak-seeking, energy calibration, background deduction and activity calculation. The detection efficiency, the correction coefficient and the MDA of 131I have been determined. The calibration coefficient has been used to correct the radioactivity measurement results of 300 mL-food sample. The results show that the measurement error of monitor for 131I radioactivity in the general food is less than 10%, which satisfies the demand of food radioactive measurement.