ARDESIA – ARray of DEtectors for Synchrotron radIation Applications: A successful project financed by INFN

The ARDESIA (ARray of DEtectors for Synchrotron radIation Applications) project, for the development of a new detection system for synchrotron radiation X-ray fluorescence (XRF) and X-ray absorption (XAS) measurements, based on arrays of SDD (Silicon Drift Detector) with high energy resolution and able to handle high count rates started the 1st of January 2015. In 2018 the ARDESIA detector was successfully tested at the DXR1 soft X-ray beamline of the INFN-LNF DAFNE-Light facility in February and at the BM08 “LISA” CRG beamline at ESRF (Grenoble – France) for about 6 months. Taking into account the great results achieved it is sure that the ARDESIA project has been a very successful collaboration between the Politecnico di Milano, the DAFNE-Light facility at the INFN-LNF and TIPFA-FBK at Trento [1-3].

ARDESIA is a four‐channel X‐ray spectrometer based on SDDs, engineered in a finger-like structure that gives the possibility to place it very near to the sample using a specific vacuum-tight translating system (Figure 1). A monolithic 2×2 SDDs matrix, 450 μm thick, represents the detection module of ARDESIA. Having these SDDs full sideward depletion and small anode capacitance, independent from the active area, they are the ideal detectors for high-count rate applications. The Fondazione Bruno Kessler (FBK -Trento, Italy) produced these SDDs using a low‐leakage manufacturing process. Two 4-channel detectors, having different pixel shapes, can alternately be mounted on ARDESIA one having square SDDS (5 mm) the other circular ones. The surface area is 25 mm2 per pixel in the first case and 20 mm2 in the second becoming, once collimated, respectively 16 mm2 and 12.6 mm2 per pixel (tests with synchrotron radiation were performed using the square geometry).

Fig. 1  The ARDESIA finger-like structure and its installation in the DAFNE-Light DXR1 experimental chamber.

 

All the electronics concerning ARDESIA was developed at the Politecnico di Milano. The signals from the SDDs anodes are collected by a four‐channel-integrated preamplifier, CUBE [2], directly wire bonded to the monolithic SDD matrix obtaining a very compact module (16 mm x 16 mm). The outputs of the preamplifier are processed also by additional internal electronics for further amplification and reset generation.

To eliminate the generation of charges at the boundaries of the different pixels, a collimator was placed over the detector. This collimator is made of Delrin® for energies up to 6 keV and of Mo for energies up to 20 keV. The characterization of the ARDESIA detection module using FWHM of the Mn Kα fluorescence line gave an energy resolution of 125.7 eV at the optimum peaking time (tpeak) of 3.2 μs and 151.5 eV at tpeak = 128 ns. Tests with synchrotron radiation, in the electrically harsh environment of the beamlines, were performed to check the detector performances in terms of energy resolution, high throughput capability, and stability over time.

At the LNF DAΦNE‐ Light DXR1 beamline, the energy resolution of the instrument was measured with the acquisition of the fluorescence spectrum from a common graphite sheet. Besides carbon, in the sample used there were also other light atomic elements like O, Na, Al, Si, P, and S. A four‐channel digital pulse processor (DPP XIA DXP‐XMAP) was used to process the data using a tpeak = 2 μs chosen for the optimum energy resolution. The ARDESIA detector was able to resolve the peaks of the low‐ Z elements present in the sample down to the Kα line of C at 277 eV. At the DXR1 beamline also the first ARDESIA XAS spectrum in fluorescence mode at the Si K-edge was measured [Figure 2].

Fig. 2  First ARDESIA XAFS spectrum measured in fluorescence mode at the DXR1 beamline.

 

 

[1] G. Bellotti, A. D. Butt, M. Carminati, C. Fiorini, L. Bombelli, G. Borghi, C. Piemonte, N. Zorzi, A. Balerna, The ARDESIA Detection Module: a 4-Channel Array of SDDs for Mcps X-Ray Spectroscopy in Synchrotron Radiation Applications, IEEE Trans. Nucl. Sci. 65, 1355, DOI: 10.1109/TNS.2018.2838673 (2018).

 

[2] I. Hafizh, G. Bellotti, M. Carminati, G. Utica, M. Gugiatti, A. Balerna, V. Tullio, G. Borghi, A. Gola, N. Zorzi, A. Capsoni, S. Coelli, L. Bombelli, C. Fiorini, ARDESIA – a Fast SDD X-ray Spectrometer for Synchrotron Applications, X-Ray Spectrometry, 1-5, DOI: 10.1002/xrs.3017 (2019).

 

[3] I. Hafizh, G. Bellotti, M. Carminati, G. Utica, M. Gugiatti, A. Balerna, V. Tullio, G. O. Lepore, G. Borghi, A. Gola, N. Zorzi, A. Capsoni, S. Coelli, L. Bombelli, C. Fiorini, Characterization of ARDESIA: A 4- Channel SDD X-ray Spectrometer for Synchrotron Measurements at High Count Rates, JINST 14, P06027, DOI: 10.1088/1748-0221/14/06/P06027 (2019)

 

Contacts:

Prof. Carlo Fiorini
INFN and Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano
Carlo.Fiorini@polimi.it

 

Dr. Antonella Balerna
INFN-LNF
Antonella.Balerna@lnf.infn.it