Andrea Santangelo

FlashCam: a fully-digital camera for the medium-sized telescopes of the Cherenkov Telescope Array

The FlashCam group is currently preparing photomultiplier-tube based cameras proposed for the medium-sized telescopes (MST) of the Cherenkov Telescope Array (CTA). The cameras are designed around the FlashCam readout concept which is the first fully-digital readout system for Cherenkov cameras, based on commercial FADCs and FPGAs as key components for the front-end electronics modules and a high performance camera server as back-end. This contribution describes the progress of the full-scale FlashCam camera prototype currently under construction, as well as performance results also obtained with earlier demonstrator setups. Plans towards the production and implementation of FlashCams on site are also briefly presented.

Readout electronics testing during mass production of FlashCam cameras for the Cherenkov Telescope Array

The Cherenkov Telescope Array (CTA) will be the future observatory for ground-based TeV gamma-ray astronomy. At two sites, one in the northern and one in the southern hemisphere, CTA will feature about one hundred telescopes of different size classes in order to significantly improve the sensitivity and energy range with respect to current Cherenkov facilities. FlashCam is a camera system proposed for the medium-sized telescopes of CTA that implements a fully-digital readout and trigger processing, which allows the reconfiguration of the trigger algorithm and the signal shaping. For the mass production of a substantial number of FlashCam cameras, efficient and reliable testing routines have been developed. In this contribution, the concept and the procedures for large-scale testing of the readout electronics are outlined. Additionally, a fast multi-channel pulse generator specifically designed for the functional testing of FlashCam FADC modules setup is presented.

The Mirror Alignment and Control System for CT5 of the H.E.S.S. experiment

Daniel Gottschall∗a, Andreas Forsterb, Antonio Bonardic, Andrea Santangeloa, and Gerd Puhlhofera for the H.E.S.S. collaboration E-mail: daniel.gottschall@astro.uni-tuebingen.de a Institut fur Astronomie und Astrophysik, Abteilung Hochenergieastrophysik, Kepler Center for Astro and Particle Physics, Eberhard-Karls-Universitat Sand 1, D 72076 Tubingen, Germany b Max-Planck-Institut fur Kernphysik P.O. Box 103980, D 69029 Heidelberg, Germany c Department of Astrophysics, Radboud University Heyendaalseweg 135, 6525 AJ Nijmegen, Netherlands

JEM-EUSO observational capabilities for different UHE primaries.

for the JEM-EUSO Collaboration Cosmic rays with energies exceeding 1018 eV, usually defined as Ultra High Energy Cosmic Rays (UHECRs), allow the possibility to study physics at energies well beyond man made accelerators. State of the art UHECR detectors have reached unprecedented exposures and have pioneered the field of Extreme Energy Cosmic Rays (EECR), cosmic rays with energies exceeding 5×1019eV. The EECR flux is extremely small, of the order of 1 particle per square kilometer per century. The next generation of UHECR and EECR detectors are expected to increase the exposure by at least one order of magnitude. The JEM-EUSO mission, currently designed to be hosted onboard the JEM module of the ISS, consists of a ultra wide field of view UV-telescope orbiting the earth at an altitude of about 400 km. JEM-EUSO will look for fluorescent UV tracks produced by Extensive Air Showers (EAS) on the night side of the earth. According to the most recent studies, the JEMEUSO mission, can be transported onto the ISS by using the SpaceX’s Dragon spacecraft. In this work we present preliminary studies on the angular and energy reconstruction performances for different types of primaries (protons, iron nuclei and gamma rays). We compare our results with previously published results for the JEM-EUSO mission in a different configuration, and find a slight improvement.

Sensitivity of the JEM-EUSO detector to UHE tau neutrino

The ultra high energy cosmic neutrinos are powerful astroph ysical probes for both astrophysical mechanisms of particle acceleration and fundamental inter ac ions. They open a window into the very distant and high-energy Universe that is difficult to ac cess by any human means and devices. The possibility of detecting them in large exposure space-b ased apparatus, like JEM-EUSO, is an experimental challenge. In this paper we present an estim ation of the feasibility of detection of UHE tau neutrino by the JEM-EUSO telescope. The interacti ons of tau-neutrino in sea water and Earth’s crust have been investigated. The estimation of the propagation length and energy of the outgoing tau-lepton shows that if its decay occurs in t he atmosphere close enough to the Earth’s surface, e.g. below∼ 5km altitude, the cascade is intensive enough and the generated light can be detected from space. We have evaluated the geome trical aperture of the JEM-EUSO detector for the Earth-skimming (horizontal and upward-go in ) tau-neutrinos by making specific modifications to the standard CORSIKA code and developing an interface to the existing ESAF (EUSO Simulation and Analysis Framework) software.

The Angular Resolution of the JEM-EUSO Mission: an updated view

The Extreme Universe Observatory onboard the Japanese Experiment Module (JEM-EUSO) is a mission being developed to observe ultra high energy cosmic rays (UHECRs) from space. JEMEUSO consists of a wide field of view UV-telescope, assisted by an atmospheric monitoring system, designed to be mounted oboard the International Space Station. JEM-EUSO will observe the extensive air showers (EAS) induced by UHE cosmic particles with energies above 3× 1019 eV by using the earth’s atmosphere as a large detector. Due to the amount of monitored target volume JEM-EUSO is expected to reach an effective aperture of approx. 2× 105 km2 sr. During its lifetime, the mission will measure several hundred events with E > 5× 1019 eV significantly improving the statistics of the most energetic part of the spectrum above the observed cut-off. In the context of the JEM-EUSO Collaboration different mission profiles are being explored. A configuration actively investigated is a telescope, mainly based on the same technologies already employed in the baseline instrument, which can be launched with the SpaceX Falcon 9 rocket and transported to the ISS by the Dragon spacecraft. This new mission configuration allows a circular design of the optics which improves the performances. In this paper we present a brief study of the expected angular resolution of this new configuration.

The Expected Angular Resolution Performance of the Tilted JEM-EUSO Instrument

JEM-EUSO (The Extreme Universe Observatory onboard the Japanese Experiment Module) is a space borne UV-telescope for the observation of UHECR induced extensive air showers (EAS). Currently in the development phase it will be attached to the ISS (International Space Station) to use the earth’s atmosphere as a large detector. Due to the large target volume it gains an effective aperture of approx. 2× 105 km2 sr — sufficient for the CR observation above an energy of 3× 1019 eV. During the mission lifetime, JEM-EUSO will observe several hundred of events above E = 5×1019 eV, significantly improving the statistics in this part of the UHECR spectrum. The default operation mode of the instrument is envisaged to be along its nadir direction. However, in a later stage of the mission, a tilting of the telescope, away from its nadir direction, is discussed as a potential strategy to further increase the exposure at the highest energies. In the tilted mode operation the exposure would significantly increase. Hence, the regime of extreme energies above 1020 eV could be explored in a reasonable amount of time. Naturally, in this setup the angular resolution of the instrument is expected to decrease. In the scope of this work we evaluate the expected angular resolution performance of the JEM-EUSO instrument in dependence of the tilting angle.