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, 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 0.3mm intrinsic resolution for gamma-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 hexag nal units arranged in a honeycomb configuration. Each go SDD unit has an active area of 8.7mm(2), for a total active area of the device of 6.7cm(2). The linear dimensions of the chip are 36x32mm(2), 28x24mm(2) 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 degrees C.