Telescope Array Experiment

Abstract

The Telescope Array is the largest hybrid cosmic ray detector in the Northern hemisphere designed to measure primary particles in 4 PeV to 100 EeV range. The main TA detector consists of an air shower array of 507 plastic scintillation counters on a 1.2 km square grid and fluorescence detectors at three stations overlooking the sky above the air shower array. The experiment and its recent measurements - spectrum, composition, and anisotropy - is reviewed. Recently the construction of the TA Low energy Extension (TALE) detector, which consists of an additional fluorescence detector and an infill array, was finished. TALE lowers the energy threshold of TA down to 4 PeV. We are also constructing the TAx4 detector to increase statistics in particular at the highest energies. The current status and the future prospects of these new TAx4 experiments is reported.