The Cosmic Ray Energy Spectrum above 2 PeV measured by the TALE Fluorescence Telescopes

Abstract

The Telescope Array (TA), deployed in the desert of central Utah, is the largest hybrid cosmic ray detector in the Northern Hemisphere. It was initially designed to observe ultra high energy cosmic rays with energies > 10$^{18}$eV. To lower the energy threshold of the experiment, TA added an extension, known as the Telescope Array Low-energy Extension (TALE), consisting of high elevation-angle telescopes and a dense graded array of scintillator surface detectors to the existing main array. Including TALE telescopes, the TA Middle Drum (MD) site has a field of view 114$^{\circ}$ in azimuth and 3-59$^{\circ}$ in elevation. In this work, I will present a measurement of the cosmic ray energy spectrum using data collected by the TALE telescopes in monocular mode with energy above 2 PeV.