【作者】 高博； 姚志国； 陈明君； 吴含荣； 王晓洁； 李会财； 刘金艳；

【Author】 GAO Bo;YAO Zhiguo;CHEN Mingjun;WU Hanrong;WANG Xiaojie;LI Huicai;LIU Jinyan;Institute of High Energy Physics,CAS;Nankai University;

【机构】 中国科学院高能物理研究所； 南开大学；

【摘要】 WCDA是LHAASO项目中的重要组成部分,主要的物理目标是巡天扫描北天区甚高能伽马射线源,提高甚高能伽马射线源的样本数量,并希望通过能谱测量的手段来解决宇宙线起源问题。WCDA采用水池结构,占地面积约78000平方米,包含3120个探测单元,以水为探测介质,利用探测单元底部放置的大尺寸光电倍增管接收宇宙线簇射次级成分在水中产生的切仑科夫光的光强和到达时间来重建原初簇射的能量、方向以及成分。为了使对辐射源探测的指向偏差小于0.1°,就要求探测器单元的时间刻度偏差小于0.1ns。针对WCDA探测器结构的特点和刻度精度需求,我们发展了一套基于LED和塑料光纤的分布式在线标定系统,本文介绍了该系统的硬件设计、在线刻度方法,并通过原型样机的初步测量,认为该系统可以满足实验需求。更多还原

【Abstract】 WCDA is one major component of LHAASO project, its main physical goal is to survey the northern sky for new VHE gamma ray sources, try to solve the problem of the cosmic ray origin through the energy spectrum measurement. The building structure of WCDA is a water pond, which covers an area of 78,000 m~2 and contains 3120 detector cells,using pure water as detecting medium. The main job of WCDA is to reconstruct the energy and direction of the origin particles by collecting Cherenkov photons which generated by air shower secondary particles in water, through the large PMT that is installed at the bottom of each detector cell. For the purpose of ensuring the angle error of the gamma source direction, the time calibration error of the detector is required to be less than 0.1 ns. Considering the building structure of WCDA, a prototype of time calibration system based on the LED and plastic optical fibers has been developed. In this paper, the design, calibration method, the test bench of the calibration prototype is introduced, which shows that it meets the requirements of time calibration.更多还原