The Calibration and Evaluation of 50 cm Box and Line Photomultiplier Tubes Designed for Hyper-Kamiokande

Abstract

Before the 2018 Super-Kamiokande (SK) detector upgrade, a hundred and forty-five 50 cm Box and Line (B&L) photomultiplier tubes (PMTs) have been carefully checked and measured in a laboratory near to the SK tank. Through various investigations including charge and timing response, required voltage, dark rate, etc., we have concluded that all received B&L PMTs were of good quality to be installed inside SK. In total 136 B&L PMTs have been picked at random and installed to replace the old SK PMTs.