Characterization of ARDESIA: a 4-channel SDD X-ray spectrometer for synchrotron measurements at high count rates

ARDESIA is an SDD-based, X-ray spectrometer, optimized for synchrotron measurements that require high count rates (>1 Mcounts/s/channel) and good energy resolution (<130 eV of FHWM Mn-Kα line at optimum shaping time, 200 eV at short shaping times). The main target applications are XRF and XAFS techniques. The detection module consists of 2×2 pixel monolithic SDD (5 mm pitch) coupled with a 4-channel version of the CUBE CMOS preamplifier. The mechanical structure of the instrument has been realized to fit inside a sample chamber with a finger-like structure. The system grants proper cooling (-40oC) and operation in vacuum. ARDESIA is also equipped with two auxiliary electronic boards: one for SDD powering and biasing and the other for closed-loop driving of two Peltier TECs. The output signals of the instrument are processed by digital pulse processors using short pulse processing times in order to achieve good spectroscopic performance at high count rates. Two different measurement campaigns were performed at synchrotron beamlines to assess the performance of the instrument. At the LNF DAΦNE-Light DXR1 soft X-ray beamline, XRF measurements on low atomic number elements (down to C-K line, 277 eV) demonstrated the good energy resolution of the spectrometer and made possible to acquire the first XAFS spectrum of Silicon K-edge in a PyrexTM glass sample. At the LISA CRG beamline at ESRF-Grenoble, XAFS measurements on different samples, such as kesterite and protochabourn'eite, were performed, demonstrating the high count rate capability and stability of the instrument over time.