重离子治癌装置中γ-γ符合时间测量系统设计  

Design of γ-γ Coincident Time Measurement System in Heavy-Ion Cancer Therapy Device

作　　者：颜俊伟 柯凌云 陈金达[1] 张秀玲[1] 杜成名[1] 杨海波[1] 王长鑫 吴俊达 苏弘[1] 千奕[1] 佘乾顺[1] 赵红赟[1] 蒲天磊 孔洁[1] YAN Jun-wei;KE Ling-yun;CHEN Jin-da;ZHANG Xiu-ling;DU Cheng-ming;YANG Hai-bo;WANG Chang-xin;WU Jun-da;SU Hong;QIAN Yi;SHE Qian-shun;ZHAO Hong-yun;PU Tian-lei;KONG Jie(Institute of Modern Physics,Chinese Academy of Sciences,Lanzhou 730000;School of Nuclear Science and Technology,University of Chinese Academy of Sciences,Shijingshan Beijing 100049;School of Physics and Telecommunications Engineering,South China Normal University,Guangzhou 510631)

机构地区：[1]中国科学院近代物理研究所,兰州730000 [2]中国科学院大学核科学与技术学院,北京石景山区100049 [3]华南师范大学物理与电信工程学院,广州510631

出　　处：《电子科技大学学报》2021年第1期24-29,共6页Journal of University of Electronic Science and Technology of China

基　　金：国家自然科学基金面上项目(11775285,11605265);国家重点研发计划(2016YFB0701001);中科院“青年创新促进会”(2016362,2019408);中科院重点部署项目(KFZD-SW-222);中科院海西创新研究院自主部署项目(FJCXY18040201)。

摘　　要：为实现重离子治癌装置中γ-γ符合时间的高精度和高分辨率测量,设计实现了符合时间的测量系统,该系统主要由高速比较器构成的定时甄别电路和基于现场可编程逻辑阵列(FPGA)的时间−数字转换(TDC)电路构成。FPGA-TDC通过“粗”时间和“细”时间结合的方法实现精确的时间测量:“粗”时间测量采用二进制计数器实现,“细”时间测量基于片内缓冲器和寄存器阵列构成的级联延迟链实现。实测结果表明,该符合时间测量系统的本征时间间隔测量分辨好于276 ps(FWHM)。构建了H8500耦合LYSO晶体阵列组成的测量系统,并对22Na 511 keVγ射线进行测试,结果表明时间测量精度优于1.12 ns(FWHM),且通过统计分析有效符合时间得到的晶体阵列位置映射散点图清晰。In order to achieve high-precision and high-resolution measurement ofγ-γcoincidence time in the heavy-ion cancer therapy device,a newly implemented coincident time measurement system is designed.The system is mainly composed of a timing discrimination circuit constructed by the high-speed comparator and FPGAbased time-to-digital converter(TDC).A precision time measurement is performed by TDC through the combination of coarse time and fine time measurement methods.The coarse time measurement is realized depending on a binary counter,and the fine time measurement is realized by using the cascade delay chain developed with the in-chip buffer unit and register array.The measured results show that the intrinsic time interval measurement resolution is better than 276 ps(FWHM).The system were tested combining with a coincidence detecting system built by H8500 coupled to LYSO scintillators arrays and the pairs ofγ-rays with 511 keV from 22Na source.The results show that the time accuracy of coincidence detecting system is better than 1.12 ns(FWHM)and the black scattered points on LYSO crystal flood image are clear and easy to be distinguished.

关 键 词：符合时间测量系统 现场可编程逻辑阵列FPGA 时间间隔测量 时间-数字转换器TDC 

分 类 号：TL824[核科学技术—核技术及应用]