The relative collection efficiency (CE) of 20-inch Photomultiplier Tubes (PMTs) cannot be measured directly, but it can be obtained by the quantum efficiency (QE) of the photocathode and the relative detection efficiency (DE) of the PMTs. The measurements of relative CE and its spherical uniformity of the 20-inch PMTs have been introduced in this manuscript, and the difference in performance between Microchannel-Plate PMT (MCP-PMT) and Dynode-PMT were shown. The CE performance for 20-inch PMTs are given and the batch test results of CE for MCP-PMTs and Dynode-PMTs are compared at the end of this manuscript.

中文翻译：

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大面积光电倍增管的相对收集效率研究

20英寸光电倍增管（PMT）的相对收集效率（CE）不能直接测量，但可以通过光电阴极的量子效率（QE）和PMT的相对检测效率（DE）来获得。本文介绍了 20 英寸 PMT 的相对 CE 及其球面均匀性的测量，并显示了微通道板 PMT (MCP-PMT) 和 Dynode-PMT 之间的性能差异。本文最后给出了 20 英寸 PMT 的 CE 性能，并对 MCP-PMT 和 Dynode-PMT 的 CE 批量测试结果进行了比较。