V. Vagelli

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

Abstract 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.

In-flight performance of the DAMPE silicon tracker

Abstract DAMPE (DArk Matter Particle Explorer) is a spaceborne high-energy cosmic ray and gamma-ray detector, successfully launched in December 2015. It is designed to probe astroparticle physics in the broad energy range from few GeV to 100 TeV. The scientific goals of DAMPE include the identification of possible signatures of Dark Matter annihilation or decay, the study of the origin and propagation mechanisms of cosmic-ray particles, and gamma-ray astronomy. DAMPE consists of four sub-detectors: a plastic scintillator strip detector, a Silicon–Tungsten tracKer–converter (STK), a BGO calorimeter and a neutron detector. The STK is composed of six double layers of single-sided silicon micro-strip detectors interleaved with three layers of tungsten for photon conversions into electron–positron pairs. The STK is a crucial component of DAMPE, allowing to determine the direction of incoming photons, to reconstruct tracks of cosmic rays and to estimate their absolute charge (Z). We present the in-flight performance of the STK based on two years of in-flight DAMPE data, which includes the noise behavior, signal response, thermal and mechanical stability, alignment and position resolution.

Development of a 16-channel matrix of photodetection sensors for medical imaging and astrophysical applications

Recen% developed near W-photosensors are currently adopted in those applications where high sensitivity and good imaging capabilities are required, especially in fields such as astroparticle physics and medical imaging. An example of such applications is the camera of the Schwarzschild Couder Medium Size Telescope prototype (pSCT) which is in construction within the Cherenkov Telescope Array experiment. The camera consists of 177 photo-detection modules grouped into sectors of 25 modules, each based on matrixes of 64 6mm × 6mm pixels of SiUcon PhotomultipUers (SiPMs). Sensors produced by the Fondazione Bruno Kessler (FBK) in Italy are currently under investigation. Here we present a complete characterization of these highly sensitive near UV sensors, the assembly procedure and metrology results on several focal plane elements.

Development and characterization of Near-UV sensitive Silicon Photomultipliers for the Schwarzschild-Couder Telescope prototype for the Cherenkov Telescope Array

Silicon Photomultipliers (SiPM) are standard sensors widely employed for applications in which high sensitivities and fast responses in the detection of low fluxes of visible and UV photons are required. The Italian Institute of Nuclear Physics (INFN), in collaboration with Fondazione Bruno Kessler (FBK), is involved in a R&D project for SiPM sensors sensitive to near UV wavelengths. The performances of the latest technology of NUV-High-Density SiPM have confirmed that the quality of the current production technology opens the possibility to employ these devices for many applications. In this contribution, we review the performances of the latest technology of NUV-High-Density SiPM and the prospects for their use in one of the designs of the camera focal planes of Schwarschild-Couder Telescope prototype, including the development of packaging procedures of single sensors into high-density multi-SiPM modules and the development of a custom front-end ASIC for a high rate waveform sampling of the SiPM signals.

Towards the development of a SiPM-based module for the camera of the Schwarzschild-Couder Telescope prototype of the Cherenkov Telescope Array

The Italian Institute of Nuclear Physics is currently involved in the development of a prototype for a camera based on Silicon Photomultipliers (SiPMs) for the Cherenkov Telescope Array (CTA), a new generation of telescopes for ground{based gamma{ray astronomy. In recent years, SiPMs have proven to be highly suitable devices for applications where high sensitivity to low{intensity light and fast responses are required. Among their many advantages are their low operational voltage when compared with classical photomultiplier tubes, mechanical robustness, and increased photo{detection efficiency (PDE). Moreover, due to the possibility of operating them during bright moonlight, SiPMs can therefore considerably increase telescope duty cycle. Here we present a full characterization of a particular type of SiPM produced in Italy by the Fondazione Bruno Kessler, which is suitable for Cherenkov light detection in the Near-Ultraviolet (NUV). This device is a High{Density (HD) NUV SiPM, based on a micro cell of 40 μm × 40 μm and with an area of 6×6 mm2, providing low levels of dark noise and high PDE peaking in the NUV band. NUV-HD SiPMs will be arranged in a matrix of 8×8 single units to become part of the focal plane of the Schwarzschild-Couder Telescope prototype for CTA. An update on recent tests of the front-end electronics based on signal sampling with the TARGET-7 chip will be given as well.

SiPM and front-end electronics development for Cherenkov light detection

G. Ambrosi (1), F. Acerbi (2), E. Bissaldi∗ †(3), A. Ferri (2), F. Giordano (3,4), A. Gola (2), M. Ionica (1), R. Paoletti (5,6), C. Piemonte (2), G. Paternoster (2), D. Simone † (3), V. Vagelli (1), G. Zappala (3), N. Zorzi (3), for the CTA Consortium ‡ (1)INFN – Sezione di Perugia, Perugia, Italy; (2)Fondazione Bruno Kessler (FBK), Trento, Italy; (3)INFN – Sezione di Bari, Bari, Italy; (4)Dipartimento Interateneo di Fisica, Universita e Politecnico di Bari, Bari, Italy; (5)INFN – Sezione di Pisa, Pisa, Italy; (6) Universita di Siena, Siena, Italy. † E-mail: Daniela.Simone@ba.infn.it,Elisabetta.Bissaldi@ba.infn.it ‡ Full consortium author list at http://cta-observatory.org