The Detection of UHECRs with the EUSO-TA Telescope

Abstract

EUSO-TA is a cosmic ray detector developed by the JEM-EUSO (Joint Experiment Missions for Extreme Universe Space Observatory) Collaboration, observing during nighttime the fluorescence light emitted along the path of extensive air showers in the atmosphere. It is installed at the Telescope Array site in Utah, USA, in front of the fluorescence detector station at Black Rock Mesa. It serves as a ground-based pathfinder experiment for future space-based missions. EUSO-TA has an optical system with two Fresnel lenses and a focal surface with 6 × 6 multi-anode photomultiplier tubes with 64 channels each, for a total of 2304 channels. The overall field of view is ∼10.6°× 10.6°. This detector technology allows the detection of cosmic ray events with high spatial resolution, having each channel a field of view of about ∼0.2° × 0.2° and a temporal resolution of 2.5 µs. First observations of ultra-high energy cosmic rays revealed the cosmic ray detection capability of EUSO-TA. The foreseen upgrade of EUSO-TA will improve the efficiency of the detector and will increase the statistics of detected events. In this work we present recent results of the detection capability of EUSO-TA and its limits. Moreover, other results about the analysis of laser pulses, stars and meteors will be discussed.

Calibration of the EUSO-TA detector with stars

“…EUSO-TA is a Photo Detector Module (PDM) test for the next EUSO experiments, in operation since February 2015. During 5 observational campaigns in years 2015-1016, UHECR events were detected and compared with simulations [2]. Measurements allow also for registration of others natural signals coming from stars, and meteors and artificial sources like the Central Laser Facility (CLF) or UV mobile laser provided by the Colorado School of Mines group.…”

“…Measurements allow also for registration of others natural signals coming from stars, and meteors and artificial sources like the Central Laser Facility (CLF) or UV mobile laser provided by the Colorado School of Mines group. The EUSO-TA telescope consists of two PMMA (polymethyl methacrylate) Fresnel lenses with effective areas equal to 0.92 m 2 [4] focusing photons on the focal surface where the PDM is placed. The PDM is composed of 36 Hamamatsu R11265-M64 Multi-Anode Photomultipliers (MAPMT).…”