Study of Extensive Air Shower Finder at TA experiment

Abstract

The Telescope Array experiment uses a hybrid detection system composed of a surface detector(SD) array and fluorescence detectos(FD). The SD array employs scintillation counters and measures lateral distribution of shower particles. The FDs are based on the air-fluorescnece detection technique and measure longitudinal developments of the electromagnetic component of extensive air shower(EAS). Therefore we can observe ultra high energy cosmic ray(UHECR) showers at the same position with different detection technique, and we determine primary energies of UHECRs in good accuracies. We have developed software package of EAS Finder for the FD detectors of the TA experiment in Utah desert. We present detailed descriptions of how to select the EAS events from raw experimental data.