Background:The lower measure limit of radiation pulse detection is usually about hundred-μA lever due to various kinds of noise existed in electronic system. However, some detectors could get the small pulse signal at the lever of decade nA and keep the noise at the lever of nA. Therefore, the conventional detection system would not collect these weak signals.Purpose: This study aims to design and implement a radiation detection system to overcome lower limitation of detection and improve the linearity of measurement for large dynamic pulse signals. Methods: The detection system noise was analyzed to explore the lower measure limit in a wide system bandwidth range. Based on the design of low noise amplifier circuit and highly dynamic digital transmission system, it could confirm the low measure limit through the theories of a small capacitor's output is in a linear correlation with input. Improvement was made according to experimental testing.Results: The system could process the weak pulse signals in the range of 0.8–680μA (peak) with 20MHz bandwidth. Aγ-radiation pulse signal below 1μA with the LSO (Lu2SiO5)+PMT (photo multiplier tube) radiation detector was successfully obtained by experiment.Conclusion: The new radiation detection system constituted with low-noise broad-band amplifier and highly dynamic digital transmission system was useful in expanding the system measure range to improve the system detection efficiency.%介绍了一种辐射探测中微弱大动态脉冲信号获取方法,着重于在一定带宽下系统可测量下限的拓展探索研究.通过低噪声放大电路设计和大动态数字化传输技术研究,利用小电容受激产生小电流信号与激励成较好的线性关系实现了可测量下限的标定,可在系统带宽20 MHz下,对0.8–680 μA(峰值)范围内的小脉冲电流信号实现有效检测.最后,经辐射探测实验,准确获得了低于1 μA的γ辐射脉冲信号.
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