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 γ-ray imaging applications. Thanks to the low electronics noise achieved at short shaping time, these devices are ideal for high-resolution and high-rate X-ray spectroscopy experiments at synchrotron sources. Moreover, small monolithic arrays of SDDs have been also used as photodetector in a first prototype of Anger camera with less 0.3 mm intrinsic resolution for γ-ray imaging. In this work we present a new monolithic array of silicon drift detectors, each one with a front-end JFET integrated at its center. It consists of a single chip composed by 77 single hexagonal units arranged in a honeycomb configuration. Each SDD unit has an active area of 8.7 mm², for a total active area of the device of 6.7 cm². The linear dimensions of the chip are 36×32 mm², 28×24 mm² approximately for the active area. It represents the largest monolithic array of SDDs with on-chip JFETs produced up to now. The results of the experimental test of the detector array, including the X-ray spectroscopy characterization of the SDDs units is presented in this work. At a single-unit level, an energy resolution of 142 eV has been measured at -10°C.