CALOCUBE: An approach to high-granularity and homogenous calorimetry for space based detectors

Future space experiments dedicated to the observation of high-energy gamma and cosmic rays will increasingly rely on a highly performing calorimetry apparatus, and their physics performance will be primarily determined by the geometrical dimensions and the energy resolution of the calorimeter deployed. Thus it is extremely important to optimize its geometrical acceptance, the granularity, and its absorption depth for the measurement of the particle energy with respect to the total mass of the apparatus which is the most important constraint for a space launch. The proposed design tries to satisfy these criteria while staying within a total mass budget of about 1.6 tons. Calocube is a homogeneous calorimeter instrumented with Cesium iodide (CsI) crystals, whose geometry is cubic and isotropic, so as to detect particles arriving from every direction in space, thus maximizing the acceptance; granularity is obtained by filling the cubic volume with small cubic CsI crystals. The total radiation length in any direction is more than adequate for optimal electromagnetic particle identification and energy measurement, whilst the interaction length is at least sufficient to allow a precise reconstruction of hadronic showers. Optimal values for the size of the crystals and spacing among them have been studied. The design forms the basis of a three-year R&D activity which has been approved and financed by INFN. An overall description of the system, as well as results from preliminary tests on particle beams will be described

The CALorimetric Electron Telescope (CALET) for high-energy astroparticle physics on the International Space Station

The CALorimetric Electron Telescope (CALET) is a space experiment, currently under development by Japan in collaboration with Italy and the United States, which will measure the flux of cosmic-ray electrons (and positrons) up to 20 TeV energy, of gamma rays up to 10 TeV, of nuclei with Z from 1 to 40 up to 1 PeV energy, and will detect gamma-ray bursts in the 7 keV to 20 MeV energy range during a 5 year mission. These measurements are essential to investigate possible nearby astrophysical sources of high energy electrons, study the details of galactic particle propagation and search for dark matter signatures. The main detector of CALET, the Calorimeter, consists of a module to identify the particle charge, followed by a thin imaging calorimeter (3 radiation lengths) with tungsten plates interleaving scintillating fibre planes, and a thick energy measuring calorimeter (27 radiation lengths) composed of lead tungstate logs. The Calorimeter has the depth, imaging capabilities and energy resolution necessary for excellent separation between hadrons, electrons and gamma rays. The instrument is currently being prepared for launch (expected in 2015) to the International Space Station ISS, for installation on the Japanese Experiment Module - Exposure Facility (JEM-EF)

Calet upper limits on X-RAY and GAMMA-RAY counterparts of GW151226

We present upper limits in the hard X-ray and gamma-ray bands at the time of the Laser Interferometer Gravitational-wave Observatory (LIGO) gravitational-wave event GW151226 derived from the CALorimetric Electron Telescope (CALET) observation. The main instrument of CALET, CALorimeter (CAL), observes gamma-rays from ∼1 GeV up to 10 TeV with a field of view of ∼2 sr. The CALET gamma-ray burst monitor (CGBM) views ∼3 sr and ∼2π sr of the sky in the 7 keV-1 MeV and the 40 keV-20 MeV bands, respectively, by using two different scintillator-based instruments. The CGBM covered 32.5% and 49.1% of the GW151226 sky localization probability in the 7 keV-1 MeV and 40 keV-20 MeV bands respectively. We place a 90% upper limit of 2 ×10-7 erg cm-2 s-1 in the 1-100 GeV band where CAL reaches 15% of the integrated LIGO probability (∼1.1 sr). The CGBM 7σ upper limits are 1.0 ×10-6 erg cm-2 s-1 (7-500 keV) and 1.8 ×10-6 erg cm-2 s-1 (50-1000 keV) for a 1 s exposure. Those upper limits correspond to the luminosity of 3-5 ×1049 erg s-1, which is significantly lower than typical short GRBs

Energy calibration of CALET onboard the International Space Station

In August 2015, the CALorimetric Electron Telescope (CALET), designed for long exposure observations of high energy cosmic rays, docked with the International Space Station (ISS) and shortly thereafter began to collect data. CALET will measure the cosmic ray electron spectrum over the energy range of 1 GeV to 20 TeV with a very high resolution of 2% above 100 GeV, based on a dedicated instrument incorporating an exceptionally thick 30 radiation-length calorimeter with both total absorption and imaging (TASC and IMC) units. Each TASC readout channel must be carefully calibrated over the extremely wide dynamic range of CALET that spans six orders of magnitude in order to obtain a degree of calibration accuracy matching the resolution of energy measurements. These calibrations consist of calculating the conversion factors between ADC units and energy deposits, ensuring linearity over each gain range, and providing a seamless transition between neighboring gain ranges. This paper describes these calibration methods in detail, along with the resulting data and associated accuracies. The results presented in this paper show that a sufficient accuracy was achieved for the calibrations of each channel in order to obtain a suitable resolution over the entire dynamic range of the electron spectrum measurement

Beam test performance of SiPM-based detectors for cosmic-ray experiments

Particle detector prototypes, equipped with Silicon PhotoMultipliers (SiPMs) and readout by dedicated front-end electronics, were tested with beams of fully ionized nuclei from boron (Z=5) to nickel (Z=28) with a kinetic energy , at the Fragment Separator (FRS) of the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt. The tested instruments included prototypes of Cherenkov and scintillation hodoscopes designed for cosmic-ray experiments in space or in the upper atmosphere. In this paper, we summarize the results from the analysis of the beam tests data and of dedicated laboratory tests to characterize the response of the photosensors, the front-end electronics and the performance of the prototypal detectors

Beam test performance of a pixelated silicon array for the charge identification of cosmic rays

A large area silicon array for the next generation of space-based experiments has been designed to determine, via multiple dE/dx measurements, the electric charge of cosmic radiation. The instrument can achieve an excellent charge discrimination, thus allowing to assess the elemental composition of charged cosmic rays at relativistic energies. Pairs of silicon sensors segmented into pixels were tested with a beam of fully ionized nuclei from boron to nickel (Z=28) with a kinetic energy of , at the Fragment Separator (FRS) of the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt. The response of the sensors to different nuclear species was accurately characterized. The results of the beam test clearly show that a double-layered silicon array can achieve single-element separation with a resolution close to 0.2 electron charge units, in the whole interval of atomic number Z under test

A custom front-end ASIC for the readout and timing of 64 SiPM photosensors

8noreservedA new class of instruments – based on Silicon PhotoMultiplier (SiPM) photosensors – are currently under development for the next generation of Astroparticle Physics experiments in future space missions. A custom front-end ASIC (Application Specific Integrated Circuit) for the readout of 64 SiPM sensors was specified in collaboration with GM-IDEAS (Norway) that designed and manufactured the ASIC. Our group developed a custom readout board equipped with a 16 bit ADC for the digitization of both pulse height and time information. A time stamp, generated by the ASIC in correspondence of the threshold crossing time, is digitized and recorded for each channel. This allows to define a narrow time window around the physics event that reduces significantly the background due to the SiPM dark count rate. In this paper, we report on the preliminary test results obtained with the readout board prototype.mixedBAGLIESI, M.G. ; AVANZINI, C.; BIGONGIARI, G.; CECCHI, R.; KIM, M.Y.; MAESTRO, P.; MARROCCHESI, P.S. ; MORSANI, F.Bagliesi, M. G.; Avanzini, C.; Bigongiari, G.; Cecchi, R.; Kim, M. Y.; Maestro, P.; Marrocchesi, P. S.; Morsani, F

Performance of a Scintillating Fiber Detector Equipped with NUV-Sensitive SiPM in a Beam of Relativistic Ions

A scintillating fiber hodoscope was tested in a beam of relativistic ions with A/Z =2 (from deuterium to nickel and above) at energies 13 and 30 GeV/amu at CERN SPS in January 2013. Individual fibers were readout by prototypal Silicon Photomutiplier (SiPM) photosensors developed by FBKTrento. Characterization and dedicated tests of the SiPM sensors were carried out in our laboratory under controlled conditions. In this paper we report the results from the analysis of the beam test data and discuss the response of the photosensors and the performance of the prototype

Scintillation and Cherenkov light detection with a 3 mm × 3mm Silicon PhotoMultiplier

9noreservedSilicon Photomultipliers (SiPM), known also as Multi Pixel Photon Counters (MPPC) are very promising solid-state photodetectors, working in the Geiger regime, with single photoelectron sensitivity. Low-light-level detection was investigated with a 3 mm × 3 mm MPPC by Hamamatsu, optically coupled with scintillators and Cherenkov acrylic radiators. Its performances were studied with a β-source, under different operating conditions. During the tests, the MPPC gain was stabilized using a temperature dependent feed-back loop on the operating voltage. The results of the tests are discussed.mixedKIM, M. Y. ; AVANZINI, C.; BAGLIESI, M. G.; BIGONGIARI, G.; LOMTADZE, T.; MAESTRO, P.; MARROCCHESI, P.S.; MORSANI, F.; ZEI, R.Kim, M. Y.; Avanzini, C.; Bagliesi, M. G.; Bigongiari, G.; Lomtadze, T.; Maestro, P.; Marrocchesi, P. S.; Morsani, F.; Zei, R

A Pipeline of Associative Memory Boards for Track Finding

We present a pipeline of associative memory boards for track finding, which satisfies the requirements of level two triggers of the next large hadron collider experiments. With respect to previous realizations, the pipelined architecture warrants full scalability of the memory bank, increased bandwidth (by one order of magnitude), and increased number of detector layers (by a factor of two). Each associative memory board consists of four smaller boards, each containing 32 programmable associative memory chips, implemented with a low-cost commercial field-programmable gate array (FPGA). FPGA programming has been optimized for maximum efficiency in terms of pattern density, while printed circuitboard design has been optimized in terms of modularity and FPGA chip density. A complete associative memory board has been successfully tested at 40 MHz; it can contain 7.2 10 3 particle trajectories