Calibration of Photomultiplier Tubes for the Fluorescence Detector of Telescope Array Experiment using a Rayleigh Scattered Laser Beam

TL;DR

This paper details the calibration process of photomultiplier tubes for the Telescope Array's fluorescence detectors using Rayleigh scattered laser photons, achieving a systematic uncertainty of 7.2%.

Contribution

It introduces a calibration method for PMTs in fluorescence detectors using Rayleigh scattering, with quantified uncertainty estimates.

Findings

Calibration uncertainty is 7.2%.

Transport adds 3.7% uncertainty.

Method improves detector calibration accuracy.

Abstract

We performed photometric calibration of the PhotoMultiplier Tube (PMT) and readout electronics used for the new fluorescence detectors of the Telescope Array (TA) experiment using Rayleigh scattered photons from a pulsed nitrogen laser beam. The experimental setup, measurement procedure, and results of calibration are described. The total systematic uncertainty of the calibration is estimated to be 7.2%. An additional uncertainty of 3.7% is introduced by the transport of the calibrated PMTs from the laboratory to the TA experimental site.