Arrays of single photon avalanche diodes (SPADs) fabricated in a 150 nm CMOS technology have been exposed to neutrons up to fluences of about <inline-formula> <tex-math notation="LaTeX">4.3 \times ...10^{10}~1 </tex-math></inline-formula> MeV neutron equivalent cm<inline-formula> <tex-math notation="LaTeX">^{-2} </tex-math></inline-formula>, with fluxes around <inline-formula> <tex-math notation="LaTeX">3 \times 10^{6}~1 </tex-math></inline-formula> MeV neutron equivalent cm<inline-formula> <tex-math notation="LaTeX">^{-2}\text{s}^{-1} </tex-math></inline-formula>. Dark count rate (DCR) was monitored during irradiation and for some time, from 5 to 23 min, depending on the irradiation step, at the end of the irradiation interval to investigate the dynamics of defect formation and short-term annealing. Measurements were performed both on single- and on dual-layer devices, where SPAD arrays are face to face bonded and read out in coincidence. A range of different DCR behaviors were detected after single neutron interaction with the device substrate, including in particular partial performance recovery following a logarithmic relaxation process, but also damped oscillation phenomena, sudden step-shaped changes, and the emergence of RTS-like fluctuations, pointing to different defect reordering dynamics.
The direct detection of high-energy cosmic rays up to the PeV region is one of the major challenges for the next generation of space-borne cosmic-ray detectors. The physics performance will be ...primarily determined by their geometrical acceptance and energy resolution. CaloCube is a homogeneous calorimeter whose geometry allows an almost isotropic response, so as to detect particles arriving from every direction in space, thus maximizing the acceptance. A comparative study of different scintillating materials and mechanical structures has been performed by means of Monte Carlo simulation. The scintillation-Cherenkov dual read-out technique has been also considered and its benefit evaluated.
Photon counting with a FDIRC Cherenkov prototype readout by SiPM arrays Marrocchesi, P.S.; Bagliesi, M.G.; Basti, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2017, Letnik:
845
Journal Article
Recenzirano
A prototype of a Focused Internal Reflection Cherenkov, equipped with 16 arrays of NUV-SiPM, was tested at CERN SPS in March 2015 with beams of relativistic ions at 13, 19 and 30GeV/n obtained from ...fragmentation of an Ar primary beam. The detector, designed to identify cosmic nuclei, features a Fused Silica radiator bar optically connected to a cylindrical mirror of the same material and an imaging focal plane of dimensions ∼4cm×3cm covered with a total of 1024 SiPM photosensors. Thanks to the outstanding performance of the SiPM arrays, the detector could be operated in photon counting mode as a fully digital device. The Cherenkov pattern was recorded together with the total number of detected photoelectrons increasing as Z2 as a function of the atomic number Z of the beam particle. In this paper, we report on the characterization and test of the SiPM arrays and the performance of the Cherenkov prototype for the charge identification of the beam particles.
The CALorimetric Electron Telescope CALET is collecting science data on the International Space Station since October 2015 with excellent and continuous performance. Energy is measured with a deep ...homogeneous calorimeter (1.2 nuclear interaction lengths, 27 radiation lengths) preceded by an imaging pre-shower (3 radiation lengths, 1mm granularity) providing tracking and
electron/proton discrimination. Two independent sub-systems identify the charge
of the incident particle from proton to iron and above (
40). CALET measures the cosmic-ray electron + positron flux up to 20 TeV, gamma rays up to 10 TeV, and nuclei up to the PeV scale. In this paper, we report the on-orbit performance of the instrument and summarize the main results obtained during the first 5 years of operation, including the electron + positron energy spectrum and the individual spectra of protons, heavier nuclei and iron. Solar modulation and gamma-ray observations are also concisely reported, as well as transient phenomena and the search for gravitational wave counterparts.
Given the good performances in terms of geometrical acceptance and energy resolution, calorimeters are the best suited detectors to measure high energy cosmic rays directly in space. However, in ...order to exploit this potential, the design of calorimeters must be carefully optimized to take into account all limitations related to space missions, due mainly to the mass of the experimental apparatus. CaloCube is a three years R&D project, approved and financed by INFN in 2014, aiming to optimize the design of a space-borne calorimeter by the use of a cubic, homogeneous and isotropic geometry. In order to maximize detector performances with respect to the total mass of the apparatus, comparative studies on different scintillating materials, different sizes of crystals and different spacings among them have been performed making use of Monte Carlo simulations. In parallel to this activity, several prototypes instrumented with CsI:Tl cubic crystals have been constructed and tested with particle beams (muons, electrons, protons and ions). Both simulations and prototypes showed that the CaloCube design leads to a good particle energy resolution (< 2% for electromagnetic showers, < 40% for hadronic showers) and a good effective geometric factor (> 3:5 m2 sr for electromagnetic showers, > 2:5 m2 sr for hadronic showers). Thanks to these performances, in 5 years of operation it would be possible to measure the ux of electrons+positrons up to some tens of TeV and the uxes of protons and nuclei up to some units of PeV/nucleon, hence extending these measurements by at least one order of magnitude in energy compared to the experiments currently operating in space.
The CALorimetric Electron Telescope (CALET) is an astroparticle physics experiment installed on the International Space Station since August 2015. The CALET mission was conceived to address several ...outstanding questions of high-energy astroparticle physics, like indirect detection of dark matter, the origin of cosmic rays (CRs), their mechanisms of acceleration and galactic propagation, the presence of possible nearby astrophysical CR sources. That can be achieved by precise measurements of the fluxes of CR electrons and gamma-rays up to the unexplored region above 1 TeV, and the energy spectra and composition of CR nuclei from a few tens of GeV to hundreds of TeV. In order to perform these observations, the instrument combines a thick total absorption PWO crystal calorimeter for energy measurement, a scintillator hodoscope for charge identi cation and thin imaging tungsten-scintillating fiber calorimeter providing accurate particle tracking and complementary charge measurement.
In this paper, we will present an overview of the main CALET results based on the data collected in the first three years of the mission.
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