This manuscript reports a study of the after-pulse properties of different types of 20-inch photomultiplier tubes (PMTs), especially for the 20-inch microchannel-plate-PMTs (MCP-PMTs) for JUNO experiment. In the study, the after-pulse rate (APR) is calculated from PMT waveforms obtained by a CAEN DT5751 waveform digitizer. We tested the after-pulse characteristics of both Dynode-PMTs and MCP-PMTs and made a thorough study on the after-pulses of high quantum efficiency (HQE) MCP-PMT for JUNO experiment, including their time distribution, after-pulse rate and the causes of different after-pulse groups through flight time analysis. Based on a fast test method, individual tests on 28 HQE-MCP-PMTs on the after-pulses were conducted at the North Night Vision Tech. Ltd. (NNVT) in Nanjing in December of 2019. This paper reports the average APR under two different definitions for HQE-MCP-PMTs and the proportions of the five different after-pulse groups.

该手稿报告了对不同类型的20英寸光电倍增管（PMT），特别是用于JUNO实验的20英寸微通道板-PMT（MCP-PMT）的脉冲后特性的研究。在这项研究中，从CAEN DT5751波形数字化仪获得的PMT波形计算出后脉冲率（APR）。我们测试了Dynode-PMT和MCP-PMT的脉冲后特性，并对JUNO实验的高量子效率（HQE）MCP-PMT脉冲后进行了深入研究，包括它们的时间分布，脉冲后速率和通过飞行时间分析了解不同脉冲群的原因。基于快速测试方法，在North Night Vision Tech上对28个HQE-MCP-PMT的后脉冲进行了单独测试。有限公司（NNVT）于2019年12月在南京。