Status of Xe/YAP PMT calibration for Telescope Array cosmic ray experiment

Abstract

The air fluorescence telescope detectors of the Telescope Array experiment in Utah desert, USA is very crutial to measure the longitudinal developments of Extensive Air Shower(EAS) directly by detecting air fluorescence lights and determine the primary energies of ultra-high energy cosmic rays. For accurate EAS observation, elaborate detector calibration is indispensable. We report on the status of Xe/YAP calibration for the measurement of characteristics of camera PMTs such as absolute gain, linearity, temperature dependence of gain.