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The new-generation high-granularity Shashlyk EM calorimeter readout by micropixel avalanche photodiodes (MAPD) with precision thermostabilization based on the Peltier element is designed, constructed end tested. MAPD-3N with superhigh pixel density 1.5×104 mm−2 and area 3×3mm2 manufactured by the Zecotek Company were used in the photodetector unit. [ABSTRACT FROM AUTHOR]

Abstract: In many detectors based on scintillators the photomultiplier tubes (PMTs) are used as photodetectors. At present photodiodes are finding wide application. Solid state photodetectors allow operation in strong magnetic fields that are often present in applications, e.g. some calorimeters operating near magnets, combined PET and MRT, etc. The photon detection efficiency (PDE) of photodiodes may reach values a few times higher than that of PMTs. Also, they are rigid, compact and have relatively low operating voltage. In the last few years Micropixel Avalanche PhotoDiodes (MAPD) have been developed and started to be used. The MAPD combines a lot of advantages of semiconductor photodetectors and has a high gain, which is close to that of the PMT. Yet, they have some disadvantages, and one of them is a limited dynamic range that corresponds to a total number of pixels. The novel deep microwell MAPD with high pixel density produced by the Zecotek Company partially avoids this disadvantage. In this paper characteristics of these photodetectors are presented in comparison with the PMT characteristics. The results refer to measurements of the gain, PDE, cross-talks, photon counting and applications: beam test results of two different “Shashlyk” EM calorimeters for COMPASS (CERN) and NICA-MPD (JINR) with the MAPD readout and a possibility of using the MAPD in PET. [ABSTRACT FROM AUTHOR]

Abstract: The main properties of two different Shashlyk EM calorimeter modules readout by novel micropixel avalanche photodiodes (MAPD) with microwell structure and very high density of pixels were studied at the T9 CERN PS test-beam facility. A MAPD-3A with density of pixels 1.5×104 mm−2 and area 3×3mm2 manufactured by Zecotek Company was used in our test. [Copyright &y& Elsevier]

Abstract: The micropixel avalanche photodiode (MAPD) is a novel photodetector with a multipixel intrinsic structure on the common silicon substrate. The typical size of each pixel is 20–30μm and the density is about 103 mm−2. Each pixel works on the common load in the Geiger mode, where the discharge is limited by an individual quenching resistor (negative feedback like in gas Geiger counter) included in each pixel feeding chain located on the common substrate. In the Geiger mode one may get an amplification factor for a single photoelectron at the level of 106 at room temperature. Measurements of gain, photon detection efficiency, one photoelectron resolution, noise and dark current for different types of MAPD were performed and compared. [Copyright &y& Elsevier]