地层元素分析仪中多道能谱采集处理电路设计

Development of A multi Channel Energy Spectrum Acquisition and Processing Circuit Information Elemental Analyzer

为满足石油测井中获取地层元素种类及质量百分比的需求,研制了一种地层元素分析仪256道能谱采集处理电路。该电路由基线恢复,零极相消和CR-RC,ADC采样保持,峰值检测,阈值比较,DSP+FPGA结构数字处理电路组成。2.775 GBq的^(241)Am-Be中子源和92.5 k Bq的226Raγ源的刻度测试表明,能量—道址具有良好线性关系,其线性相关系数为0.999 6,最大偏差为0.625%。经实验验证,256道能谱采集处理电路具有高稳定性,良好重复性,最大计数率可达100 k/s。

In order to satisfy the requirement of the types of element and the mass percentage of the formation in the oil well logging, a 256 channel energy speetrum acquisition and processing circuit is developed. The circuit consists of baseline restorer, pole zero cancellation and CR - RC, ADC sampling, peak detection, threshold comparison, DSP ＋ FPGA structure digital processing circuit. Calibration tests of 2. 775 GBq ^241Am - Be neu- tron source and 92.5 kBq^226Ra gamma source show that the energy channel site has a good linear relationship, the linear correlation coefficient is 0.999 6, the maximum deviation is 0.625 %. The experimental results show that the 256 energy spectrum acquisition circuit has high stability, good repeatability, the maximum count rate of up to 100 k/s.