Application of Silicon Drift Detectors for the Readout of a CdWO4 Scintillating Crystal

In this paper, an application of silicon drift detectors (SDDs) as photodetectors for large inorganic scintillators is presented. In particular, a 2.3 x 2.3 x 1.5 cm
³
CdWO
₄
crystal has been coupled to a 3 x 2 matrix of 8 x 8 mm
²
SDDs both cooled at 125 K, obtaining a scintillation detector whose performances are tested by measuring the y rays emitted by a
²²⁸
Th source. The SDDs, characterized by high quantum efficiency and low electronic noise, are suitable candidates as photodetectors for high-resolution gamma-ray spectroscopy detectors. On the other hand, CdWO
₄
is an interesting crystal for the study of rare nuclear decays, such as the possible neutrinoless double beta decay (0νββ) of
¹¹⁶
Cd. With this prototype, a full-width at halfmaximum resolution of 3.09 ± 0.05% at 2615 keV has been measured. This result provides a first validation of the application of this technology to rare event searches.