基于FPGA的磁量热计数据采集系统研制  

Development of FPGA-Based Data Acquisition System for Metallic Magnetic Calorimeter

作　　者：李阳 徐利军[1] 刘蕴韬[1] 朱保吉 张雨禾 金琦 周宗正 李元桥 林敏[1] 郝丽杰[1] 王洪亮 金诗淳 LI Yang;XU Lijun;LIU Yuntao;ZHU Baoji;ZHANG Yuhe;JIN Qi;ZHOU Zongzheng;LI Yuanqiao;LIN Min;HAO Lijie;WANG Hongliang;JIN Shichun(National Key Laboratory for Metrology and Calibration Techniques,China Institute of Atomic Energy,Beijing 102413,China)

机构地区：[1]中国原子能科学研究院计量与校准技术重点实验室,北京102413

出　　处：《同位素》2024年第5期463-471,共9页Journal of Isotopes

摘　　要：磁量热计是基于量热法的低温粒子探测器,可实现射线高分辨测量。为解决磁量热信号微弱易受到噪声影响导致信号采集困难的难题,本研究基于现场可编程门阵列(FPGA)研发了一套磁量热计数据采集系统,并对搭建的系统进行测试,成功实现了^(60)Co能谱数据和磁量热信号噪声谱的采集,且能谱展宽与信号放大倍数之间的线性拟合R2达到0.978 1,表明该系统可有效实现信号采集。在离线模式下使用梯形滤波、平顶尖峰滤波、高斯滤波对传统核探测器信号、模拟及实际的磁量热信号分别进行成形效果及能量分辨力优化效果的对比,三者中平顶尖峰滤波性能最优越,可以使高纯锗对^(241)Am源59.54 keV的γ能量分辨力从0.598 keV提高到0.536 keV,验证了数字滤波的必要性,可为磁量热计数字滤波方法选择提供可靠依据。Metallic magnetic calorimeters are a class of low-temperature particle detectors based on calorimetry,utilizing metallic paramagnetic temperature sensors to convert the temperature rise of an absorber upon the absorption of incident particle energy into a change in magnetic flux,which detected by a superconducting quantum interference device(SQUID).This process enables highresolution measurements of radiation with exceptional precision.However,metallic magnetic calorimeter signals are inherently weak and highly susceptible to noise,making the extraction of pulse amplitude a significant challenge.Digital signal processing(DSP) plays a crucial role in the data processing of metallic magnetic calorimeter by employing digital filtering techniques to shape the signals and enhance energy resolution.This paper introduces a data acquisition system for metallic magnetic calorimeter based on a field-programmable gate array(FPGA),designed for highspeed signal acquisition,real-time control,signal processing,and display of spectra through an upper computer.Testing of the system yielded successful acquisition of both Co-60 spectra data and noise spectrum of metallic magnetic calorimeter.The linear correlation coefficient of R2 reached 0.978 1,demonstrates the system's effective signal acquisition capability.In offline mode,the shaping effects and energy resolution enhancement of traditional nuclear detector signals,simulated,and actual metallic magnetic calorimeter signals were compared using three filtering methods:trapezoidal,cusp,and gaussian filtering.The cusp filter proved to be the most effective,significantly improving the energy resolution of high-purity germanium spectra from 0.598 keV to 0.536 keV.This enhancement validates the correctness of digital signal processing and provides a reliable basis for the selection of digital filtering methods for metallic magnetic calorimeter.In summary,our research presents a comprehensive approach to metallic magnetic calorimeter signal acquisition and processing,highlighting the

关 键 词：FPGA 数据采集系统 梯形滤波 平顶尖峰滤波 高斯滤波 

分 类 号：TL99[核科学技术—核技术及应用]