SiPM and front-end electronics development for Cherenkov light detection

The Italian Institute of Nuclear Physics (INFN) is involved in the development of a demonstrator for a SiPM-based camera for the Cherenkov Telescope Array (CTA) experiment, with a pixel size of 6$\times$6 mm$^2$. The camera houses about two thousands electronics channels and is both light and compact. In this framework, a R&D program for the development of SiPMs suitable for Cherenkov light detection (so called NUV SiPMs) is ongoing. Different photosensors have been produced at Fondazione Bruno Kessler (FBK), with different micro-cell dimensions and fill factors, in different geometrical arrangements. At the same time, INFN is developing front-end electronics based on the waveform sampling technique optimized for the new NUV SiPM. Measurements on 1$\times$1 mm$^2$, 3$\times$3 mm$^2$, and 6$\times$6 mm$^2$ NUV SiPMs coupled to the front-end electronics are presentedComment: In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions at arXiv:1508.0589

Measurements and tests on FBK silicon sensors with an optimized electronic design for a CTA camera

In October 2013, the Italian Ministry approved the funding of a Research & Development (R&D) study, within the "Progetto Premiale TElescopi CHErenkov made in Italy (TECHE)", devoted to the development of a demonstrator for a camera for the Cherenkov Telescope Array (CTA) consortium. The demonstrator consists of a sensor plane based on the Silicon Photomultiplier (SiPM) technology and on an electronics designed for signal sampling. Preliminary tests on a matrix of sensors produced by the Fondazione Bruno Kessler (FBK-Trento, Italy) and on electronic prototypes produced by SITAEL S.p.A. will be presented. In particular, we used different designs of the electronics in order to optimize the output signals in terms of tail cancellation. This is crucial for applications where a high background is expected, as for the CTA experiment.Comment: 5 pages, 6 figures; Proceedings of the 10th Workshop on Science with the New Generation of High-Energy Gamma-ray experiments (SciNeGHE) - PoS(Scineghe2014)00

Atmospheric production of energetic protons, electrons and positrons observed in near Earth orbit

Abstract Substantial fluxes of protons and leptons with energies below the geomagnetic cutoff have been measured by the AMS experiment at altitudes of 350–390 km, in the latitude interval ±51.7°. The production mechanisms of the observed trapped fluxes are investigated in detail by means of the FLUKA Monte Carlo simulation code. All known processes involved in the interaction of the cosmic rays with the atmosphere (detailed descriptions of the magnetic field and the atmospheric density, as well as the electromagnetic and nuclear interaction processes) are included in the simulation. The results are presented and compared with experimental data, indicating good agreement with the observed fluxes. The impact of the secondary proton flux on particle production in atmosphere is briefly discussed

Architecture and First Characterization of the Microstrip Silicon Detector Data Acquisition of the FOOT experiment

Oncological hadrontherapy is a novel technique for cancer treatment that improves over conventional radiotherapy by having higher effectiveness and spatial selectivity. The FOOT (FragmentatiOn Of Target) experiment studies the nuclear fragmentation caused by the interactions of charged particle beams with patient tissues in Charged Particle Therapy. Among the several FOOT detectors, the silicon Microstrip Detector is part of the charged-ions-tracking magnetic spectrometer. The detector consists of three x-y planes of two silicon microstrip detectors arranged orthogonally between each other to enable tracking capabilities. Ten analog buffer chips and fi ve ADCs read out each detector. A Field-Programmable Gate Array collects the output of the ADCs of an x-y plane, possibly processes the data, and forms a packet to be sent to the experiment central data acquisition. This data acquisition system shall withstand the trigger rate and detector’s throughput at any time. In this work, we discuss the architecture of the data acquisition system—in particular of the silicon microstrip detector one—and the fi rst results obtained from the x-y plane’s prototype

INFN Camera demonstrator for the Cherenkov Telescope Array

The Cherenkov Telescope Array is a world-wide project for a new generation of ground-based Cherenkov telescopes of the Imaging class with the aim of exploring the highest energy region of the electromagnetic spectrum. With two planned arrays, one for each hemisphere, it will guarantee a good sky coverage in the energy range from a few tens of GeV to hundreds of TeV, with improved angular resolution and a sensitivity in the TeV energy region better by one order of magnitude than the currently operating arrays. In order to cover this wide energy range, three different telescope types are envisaged, with different mirror sizes and focal plane features. In particular, for the highest energies a possible design is a dual-mirror Schwarzschild-Couder optical scheme, with a compact focal plane. A silicon photomultiplier (SiPM) based camera is being proposed as a solution to match the dimensions of the pixel (angular size of ~ 0.17 degrees). INFN is developing a camera demonstrator made by 9 Photo Sensor Modules (PSMs, 64 pixels each, with total coverage 1/4 of the focal plane) equipped with FBK (Fondazione Bruno Kessler, Italy) Near UltraViolet High Fill factor SiPMs and Front-End Electronics (FEE) based on a Target 7 ASIC, a 16 channels fast sampler (up to 2GS/s) with deep buffer, self-trigger and on-demand digitization capabilities specifically developed for this purpose. The pixel dimensions of $6\times6$ mm$^2$ lead to a very compact design with challenging problems of thermal dissipation. A modular structure, made by copper frames hosting one PSM and the corresponding FEE, has been conceived, with a water cooling system to keep the required working temperature. The actual design, the adopted technical solutions and the achieved results for this demonstrator are presented and discussed.Comment: In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions at arXiv:1508.0589

Internal alignment and position resolution of the silicon tracker of DAMPE determined with orbit data

The DArk Matter Particle Explorer (DAMPE) is a space-borne particle detector designed to probe electrons and gamma-rays in the few GeV to 10 TeV energy range, as well as cosmic-ray proton and nuclei components between 10 GeV and 100 TeV. The silicon-tungsten tracker-converter is a crucial component of DAMPE. It allows the direction of incoming photons converting into electron-positron pairs to be estimated, and the trajectory and charge (Z) of cosmic-ray particles to be identified. It consists of 768 silicon micro-strip sensors assembled in 6 double layers with a total active area of 6.6 m$^2$. Silicon planes are interleaved with three layers of tungsten plates, resulting in about one radiation length of material in the tracker. Internal alignment parameters of the tracker have been determined on orbit, with non-showering protons and helium nuclei. We describe the alignment procedure and present the position resolution and alignment stability measurements

The internal alignment and position resolution of the AMS-02 silicon tracker determined with cosmic-ray muons

Abstract The Alpha Magnetic Spectrometer is a large acceptance cosmic-ray detector ( 0.5 m 2 sr ) designed to operate at an altitude of 400 km on the International Space Station. The AMS-02 silicon tracker contains 2264 silicon microstrip sensors (total active area 6.75 m 2 ). The internal alignment parameters of the assembled tracker have been determined on the ground with cosmic-ray muons. The alignment procedure is described and results for the alignment precision and position resolution are reported

Results and applications of SiPM photodetectors from FBK-irst by the DASIPM Collaboration

Silicon Photomultipliers (SiPMs) and SiPM matrices optimized for the detection of blue light have been developed at FBK-irst. The first devices produced are composed of 625 microcells with 40 μm × 40 μm size, in a 1mm × 1mm active area. The devices have a breakdown voltage around 30 V, and a gain about 106. The DASIPM Collaboration is evaluating their performance and possible applications in high-energy physics, space physics and medical imaging. Dedicated front-end electronics are also being developed

Protons in near earth orbit

The proton spectrum in the kinetic energy range 0.1 to 200 GeV was measured by the Alpha Magnetic Spectrometer (AMS) during space shuttle flight STS-91 at an altitude of 380 km. Above the geomagnetic cutoff the observed spectrum is parameterized by a power law. Below the geomagnetic cutoff a substantial second spectrum was observed concentrated at equatorial latitudes with a flux ~ 70 m^-2 sec^-1 sr^-1. Most of these second spectrum protons follow a complicated trajectory and originate from a restricted geographic region.Comment: 19 pages, Latex, 7 .eps figure