改进型过阈时间法多通道幅度测量中的基线恢复方法  

Baseline Restoration Method in Multi-channel Dynamic Time-over-threshold System Using Fast Trigger

作　　者：陶峰 田阳[1,2] TAO Feng;TIAN Yang(Department of Engineering Physics,Tsinghua University,Beijing 100084,China;Key Laboratory of Particle&Radiation Imaging(Tsinghua University),Ministry of Education,Beijing 100084,China)

机构地区：[1]清华大学工程物理系,北京100084 [2]清华大学粒子技术与辐射成像教育部重点实验室,北京100084

出　　处：《核电子学与探测技术》2024年第1期1-5,共5页Nuclear Electronics & Detection Technology

基　　金：北京市自然科学基金资助项目(资助编号1222024)。

摘　　要：过阈时间法将信号幅度测量转换成为对过阈时间的测量。采用可变阈值的改进型过阈时间法能够显著优化系统的线性,使其在能谱测量中发挥作用。其所需的比较器和时间数字转换器均可在FPGA内实现,在多通道幅度测量中可大大简化数据采集系统。过阈时间法对波形和基线稳定性有较高要求,在高计数率下,堆积和基线偏移会对测量造成影响。提出一种通过可变阈值采样基线的校正方法,基于信号模拟系统验证了该方法的可行性,初步分析了其基线恢复的效果。该方法可显著提升过阈时间法在高计数率下的稳定性。Multi-channel energy resolving system can be simplified by time-over-threshold(TOT)method.Comparators and time-to-digital convertors can be realized in an FPGA.One feasible method to improve the linearity is using dynamic threshold.As TOT method is based on the pulse shape,the performance will be affected by the pile-up and baseline drift at high count rate.A baseline sampling method is proposed to reduce the error caused by baseline drift in a dynamic TOT system.The dynamic threshold is used to sample the baseline and the result is subtracted from the TOT width.The feasibility is verified by signal simulation.The stability of dynamic TOT method can be improved at high count rate according to the simulation result.

关 键 词：过阈时间法 多通道 基线恢复 

分 类 号：TN722.7[电子电信—电路与系统]