Characterization of the photomultiplier tubes for the scintillation detectors of GRANDProto35 experiment

TL;DR

This paper characterizes the photomultiplier tubes used in the scintillation detectors of the GRANDProto35 experiment, focusing on their key performance parameters to optimize detection capabilities.

Contribution

It provides detailed measurements and calibration of the Hamamatsu R7725 PMT's characteristics for the first time in this context.

Findings

Gain and SPE resolution characterized

Transit time spread measured

Dynamic range and temperature effects analyzed

Abstract

GRANDProto35 is the first stage of the GRAND project. It will be composed of an array of 35 radio antennas and 24 scintillation detectors, the radio and scintillating subarrays being triggered independently. The scintillation detector array allow to cross check,through an offline treatment, if the selected radio candidates are indeed air shower events and thus quantitatively determine the detection efficiency of the radio array. The Hamamatsu R7725 is candidate for the scintillation detector photomultiplier. The characteristics of the PMT will directly affects the time and energy resolution, dynamic detection range of a scintillation detector.In order to cover the large dynamic range, voltage divider circuit featured with dual-readoutwas designed for the PMT. In this paper,details about the system setup, measurement method and results will be described. Some characteristics of PMT were calibrated and researched: the absolution gain, single photoelectron (SPE) energy resolution, transit time spread (TTS), linear dynamic range and temperature dependence of PMT gain.