Calibration and testing of a prototype of the JEM-EUSO telescope on Telescope Array site

¹ RIKEN, ASI Institute and INFN Sezione di Roma Tor Vergata
² Osaka City University Faculty Administration Department, Sugimoto-ku, Osaka 558-8585, Japan
³ Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba, 277-8582, Japan
⁴ Institute for High Energy Astrophysics and Department of Physics, University of Utah, Salt Lake City, UT 84112-0830, USA
⁵ Graduate School of Science and Engineering, Tokyo Institute of Technology, Meguro, Tokyo 152-8551, Japan
⁶ Interdisciplinary Graduate School of Medicine and Engineering, Mechanical Systems Engineering, University of Yamanashi, Kofu, Yamanashi 400-8511, Japan

^a e-mail: casolino@roma2.infn.it

Abstract

Aim of the TA-EUSO project is to install a prototype of the JEM-EUSO telescope on the Telescope Array site in Black Rock Mesa, Utah and perform observation of natural and artificial ultraviolet light. The detector consists of one Photo Detector Module (PDM), identical to the 137 present on the JEM-EUSO focal surface. Each PDM is composed by 36 Hamamatsu multi-anode photomultipliers (64 channels per tube), for a total of 2304 channels. Front-End readout is performed by 36 ASICS, with trigger and readout tasks performed by two FPGA boards that send the data to a CPU and storage system. Two, 1 meter side square Fresnel lenses provide a field-of-view of 8 degrees. The telescope will be housed in a container located in front of the fluorescence detector of the Telescope Array collaboration, looking in the direction of the ELF (Electron Light Source) and CLF (Central Laser Facility). Aim of the project is to calibrate the response function of the EUSO telescope with the TA fluorescence detector in presence of a shower of known intensity and distribution. An initial run of about six months starting from end 2012 is foreseen, during which we expect to observe, triggered by TA electronics, a few cosmic ray events which will be used to further refine the calibration of the EUSO-Ground with TA. Medium term plans include the increase of the number of PDM and therefore the field of view.