Advanced X-ray PIxel Detector (AXPiDe v2.0): new modular multichannel detector based on SDD available at the XAFS beamline of Elettra

This contribution will report on a detection system specially designed and developed to fulfil the needs of X-ray Absorption Spectroscopy (XAS) experiments at the XAFS beamline of the ELETTRA synchrotron. It is composed of 8 monolithic multipixel arrays of Silicon Drift Detectors (SDDs), each comprising 8 cells (3x3 mm2) fabricated on 450-µm-thick, n-type, high-purity silicon wafers, and it includes a Tungsten collimation system. This results in 64 independent cells for a total collimated area of 500 mm2. All arrays are connected to separate back-end electronics, and they are calibrated, aligned and summed together by the acquisition software. The system includes custom-made, ultra-low-noise front-end electronics, a dedicated acquisition system, digital filtering, and temperature control and stabilization. The sensor is optimized to operate in the energy range 3-30 keV. A dedicated acquisition software, Fluorescence Instrumentation Control Universal Software (FICUS), developed using NI LabVIEW and fully integrated with the control system of the beamline, allows the instrument performance to be controlled, fine-tuned and monitored. Accurate characterization performed at room temperature at the XAFS beamline in Elettra demonstrated very interesting results in terms of energy resolution, with a FWHM below 170 eV at the 5.9 keV Mn-Kα line for the sum of all cells, a high count rate capability with an excellent peak-to-background ratio. All these specifications make it possible to collect high-data-quality XAS spectra on diluted elements embedded in heavy matrices, which can be exploited to improve the throughput of the beamline, as well as to follow slow kinetics.