A monolithic array of 77 Silicon Drift Detectors for X-ray spectroscopy and gamma-ray imaging applications

Monolithic arrays of Silicon Drift Detectors (SDDs) have been employed successfully in X-ray spectroscopy and gamma-ray imaging applications. Thanks to the low electronics noise achieved at short shaping time, the SDD is an ideal device for high-resolution and high-rate X-ray spectroscopy experiments at synchrotron sources. Moreover, small monolithic arrays of SDDs have also been used as photodetector of the scintillation light in a first prototype of Anger Camera for gamma-ray imaging characterized by an intrinsic resolution better than 0.3 mm. In this work we present a new large-area monolithic array of Silicon Drift Detectors. It consists o a single chip composed by 77 single hexagonal units, each one with a front-end JFET integrated in its center, arranged in a honeycomb configuration. Each SDD unit has an active area of 8.7 mm(2), for a total active area of the device of 6.7 cm(2). The linear dimensions of the active area are approximately 29 x 26 mm(2). It represents the largest monolithic array of SDDs with on-chip JFETs produced up to now for X-ray and gamma-ray detection. The results achieved in the experimental characterization of a first prototype of the detector array are presented. They include also the preliminary X-ray spectroscopy characterization of the SDD's units. The energy resolution measured at 6 keV with the single unit of the array is of 142 eV at -10 degrees C.