多通道能谱分析系统的通道复用技术

Multiplexing technology for multi-channel energy spectrum systems

能谱分析是一种重要的核辐射分析方法,探测器将接收到的核辐射脉冲转化为电信号,经电路整形后送入ADC进行数模转换,然后再经处理器处理得到能谱数据。ADC采样率和采样位数越大,测得的核脉冲信号就越准确,系统的能量分辨率就越高。而高采样率与采样位数往往不可兼得,为了提高能谱分析系统采样率,提出采用通道复用技术让多个16位ADC并行采样以提高采样率。使用NI公司的8通道USB-7845R数据采集卡,将两个采样率为500k/s的ADC复用得到1 M/s的采样率,构建了4通道的能谱分析系统,验证了通道复用技术的可行性和稳定性。实验结果表明,多通道复用技术可以在不改变硬件电路的情况下提高能谱分析系统的采样率,从而提高能量分辨率。

Energy spectrum is one of the best important methods for the nuclear radiation analysis .The nuclear pulse received by the detector is translated into electrical signal and sent into ADC after shaping ,followed by processing of the MCU and output of the spectral data .The higher sampling rate can detect the more accurate nuclear signal and achieve higher energy resolution .But high sampling rate and sample bits cannot have both .Multiplexing technique is proposed to control multiple 16 bits ADCs sampling parallel to realize a higher sampling rate .Based on the NI USB‐7845R Multifunction RIO Card ,the multi‐channel spectrum analysis system with 1 M/s sampling rate is realized by combination of two 500 k/s ADC , the system performance and the stability all are verified in this paper . The experimental results show that the multiplexing technology can be used to improve both the sampling rate and the energy resolution of the energy spectrum analysis system under the condition of without changing the hardware circuit .