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 2.3x2.3x1.5 cm(3) CdWO4 crystal has been coupled to a 3 x 2 matrix of 8x8 mm(2) SDDs both cooled at 125 K, obtaining a scintillation detector whose performances are tested by measuring the gamma rays emitted by a Th-228 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, CdWO4 is an interesting crystal for the study of rare nuclear decays, such as the possible neutrinoless double beta decay (0 nu beta beta) of Cd-116. With this prototype, a full-width at half-maximum 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