基于Gaussian-LM算法的便携式多道γ能谱仪自动稳谱研究

Research on Gaussian-LM algorithm based spectral auto stabilization of multi-channel gamma spectrometer

针对便携式多道γ能谱仪测量过程中因温度变化造成谱线漂移的问题,提出了一种特征峰自动稳谱方法。该方法使用LM算法对Gaussian拟合函数进行参数寻优,获取当前测量过程中特征峰峰位道址,依据谱漂移量利用PID控制算法调节高压控制字继而进行相应的高压补偿,实现系统自动稳谱功能。试验结果表明,1024道便携式γ能谱仪在-20~50℃范围内实测最大谱漂不超过±3道。因此,研究的自动稳谱方法可为野外γ能谱准确测量提供技术支撑。

In order to solve the problem of gamma spectrum drift caused by the influence of ambient temperature in the measurement of portable multi-channel gamma spectrometer,an spectral auto stabilization method based on the characteristic peaks of nuclides is proposed.In this method,Levenberg-Marquart(LM)algorithm is used to optimize the parameters of Gaussian fitting function to obtain the channel corresponding to the characteristic peaks position of nuclides in the current measurement process.According to gamma spectrum drift,the PID control algorithm is used to adjust variable quantity of system high voltage so as to make corresponding high voltage compensation,and to achieve the spectral auto stabilization function of the system.The result showed that the maximum drift of the measured peak location for the 1024 channels instrument under-20 to 50℃is less than±3 channels compared with the theoretical peak location,which can provide technical support for the accurate measurement of the field gamma energy spectrum.