Qualification tests of 997 8-inch photomultiplier tubes for the water Cherenkov detector array of the LHAASO experiment

TL;DR

This paper reports on the qualification testing of 997 8-inch photomultiplier tubes used in the water Cherenkov detector array of the LHAASO experiment, including design, testing procedures, and results.

Contribution

It introduces a high dynamic range PMT base design, details the batch testing system, and presents test results for nearly a thousand PMTs for the LHAASO WCDA.

Findings

High performance of tested PMTs confirmed

Successful implementation of high dynamic range design

Reliable batch testing methodology established

Abstract

The Large High-Altitude Air Shower Observatory (LHAASO) is being built at Haizi Mountain, Sichuan province of China at an altitude of 4410 meters. One of its main goals is to survey the northern sky for very-high-energy gamma ray sources via its ground-based water Cherenkov detector array (WCDA). 900 8-inch photomultiplier tubes (PMTs) CR365-02-1 from Beijing Hamamatsu Photon Techniques INC. (BHP) are installed in the WCDA, collecting Cherenkov photons produced by air shower particles crossing water. The design of the PMT base with a high dynamic range for CR365-02-1, the PMT batch test system, and the test results of 997 PMTs are presented in this paper.