A Silicon Drift Detector-CMOS front-end system for high resolution X-ray spectroscopy up to room temperature

A system constituted by a Silicon Drift Detector (SDD), fabricated with an innovative technology for minimizing the anode current, and a new CMOS charge sensitive preamplifier (CSA), designed for ultimate low noise performance, has been realized and experimentally characterized. The SDD is hexagonal with an active area of 13 mm 2 . The current density measured at the anode with the detector in operating condition is 25 pA/cm 2 at +20°C. The CSA—named SIRIO—has intrinsic Equivalent Noise Charge (ENC) ranging from 2.9 to 1.5 electrons r.m.s. at 0.8 μs and 11 μs peaking times at room temperature, respectively. With the SDD-SIRIO system at +21°C, an energy resolution of 141 eV FWHM on the 55 Fe line at 5.9 keV and 74 eV FWHM on the pulser line with a noise threshold of 170 eV have been measured at 0.8 μs peaking time. The system has been tested from −30°C to +30°C with energy resolution from 124 eV to 148 eV FWHM at 5.9 keV. A moderate cooling at +10°C is sufficient to reach 133 eV FWHM at 5.9 keV.