Orateurs
Description
EUSO-TA is a cosmic ray detector developed by the JEM-EUSO Collaboration (Joint Experiment Missions for Extreme Universe Space Observatory), observing during nighttime the fluorescence light emitted through 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 in Black Rock Mesa, as ground-based pathfinder experiment for a future space-based mission.
EUSO-TA has an optical system with two Fresnel lenses and a focal surface with $6\times6$ multi-anode photomultiplier tubes with 64 channels each, for a total of 2304 channels. The overall field of view is $10.6°\times10.6°$. This detector technology allows the detection of cosmic ray events with high spatial resolution, having each channel a field of view of about $0.2°\times0.2°$ and a temporal resolution of $2.5\,\mu \mbox{s}$.
The observation of the first ultra high energy cosmic rays, supported by dedicated simulation studies, revealed the cosmic ray detection capability of EUSO-TA. Simulations were also used to test the trigger algorithm which will make the detector autonomous rather than working in coincidence with the Telescope Array fluorescence detectors. The foreseen upgrade of EUSO-TA will improve the efficiency of the detector and will increase the statistics of detected events.
In this work I will report on the recent results about the detection capability of EUSO-TA and its limits, passing through the variation of signals depending on the energy and geometry of the extensive air showers.
