We present a spectroscopic system constituted by a Silicon Drift Detector (SDD) coupled to a CMOS charge sensitive preamplifier, named SIRIO, specifically designed to reach ultimate low noise levels. ...The SDD, with an active area of 13 mm 2 , has been manufactured by optimizing the production processes in order to reduce the anode current, successfully reaching current densities between 17 pA/cm 2 and 25 pA/cm 2 at + 20 ° C for drift fields ranging from 100 V/cm to 500 V/cm. The preamplifier shows minimum intrinsic noise levels of 1.27 and 1.0 electrons r.m.s. at +20 ° C and -30 ° C, respectively. At room temperature (+ 20 ° C) the 55 Fe 5.9 keV and the pulser lines have 136 eV and 64 eV FWHM, respectively, corresponding to an equivalent noise charge of 7.4 electrons r.m.s.; the noise threshold is at 165 eV. The energy resolution, as measured on the pulser line, ranges from 82 eV FWHM (9.4 electrons r.m.s.) at + 30 ° C down to 29 eV FWHM (3.3 electrons r.m.s.) at - 30 ° C.
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 super(2). The current density measured at the anode with the detector in operating condition is 25 pA/cm super(2) at +20degreesC. The CSA-named SIRIO-has intrinsic Equivalent Noise Charge (ENC) ranging from 2.9 to 1.5 electrons r.m.s. at 0.8 mus and 11 mus peaking times at room temperature, respectively. With the SDD-SIRIO system at +21degreesC, an energy resolution of 141 eV FWHM on the super(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 mus peaking time. The system has been tested from -30degreesC to +30degreesC with energy resolution from 124 eV to 148 eV FWHM at 5.9 keV. A moderate cooling at +10degreesC is sufficient to reach 133 eV FWHM at 5.9 keV.
The TwinMic spectromicroscope at Elettra is a multipurpose experimental station for full-field and scanning imaging modes and simultaneous acquisition of X-ray fluorescence. The actual LEXRF ...detection setup consists of eight single-cell Silicon Drift Detectors (SDD) in an annular configuration. Although they provide good performances in terms of both energy resolution and low-energy photon detection efficiency, they cover just about 4% of the whole photoemission solid angle. This is the main limitation of the present detection system, since large part of the emitted photons is lost and consequently a high acquisition time is required. In order to increase the solid angle, a new LEXRF detection system is being developed within a large collaboration of several institutes. The system, composed of 4 trapezoidal multi-cell silicon drift detectors, covers up to 40% of the photoemission hemisphere, so that this geometry provides a 10 times improvement over the present configuration. First measurements in the laboratory and on the TwinMic beamline have been performed in order to characterize a single trapezoidal detector, configured and controlled by means of two multichannel ASICs, which provide preamplification, shaping and peak-stretching, connected to acquisition electronics based on fast ADCs and FPGA and working under vacuum.
The XAFS beamline at Elettra Synchrotron in Trieste combines X-ray absorption spectroscopy and X-ray diffraction to provide chemically specific structural information of materials. It operates in the ...energy range 2.4-27 keV by using a silicon double reflection Bragg monochromator. The fluorescence measurement is performed in place of the absorption spectroscopy when the sample transparency is too low for transmission measurements or the element to study is too diluted in the sample. We report on the development and on the preliminary tests of a new prototype detector based on Silicon Drift Detectors technology and the SIRIO ultra low noise front-end ASIC. The new system will be able to reduce drastically the time needed to perform fluorescence measurements, while keeping a short dead time and maintaining an adequate energy resolution to perform spectroscopy. The custom-made silicon sensor and the electronics are designed specifically for the beamline requirements.
We present an Application Specific Integrated Circuit (ASIC), named VEGA-1, designed and manufactured for low-power analog pulse processing of signals from Silicon Drift Detectors (SDDs). The VEGA-1 ...ASIC consists of an analog and a digital/mixed-signal section to achieve all the functionalities and specifications required for high-resolution X-ray spectroscopy in the energy range from 500 eV to 60 keV with low power consumption. The VEGA-1 ASIC has been designed and manufactured in 0.35- mu m CMOS mixed-signal technology in single and 32-channel version with dimensions of 200 mu m x 500 mu m per channel. A minimum intrinsic ENC of 12 electrons r.m.s. at 3.6 mu s shaping time and room temperature is measured for the ASIC without detector. The VEGA-1 has been tested with Q10-SDD designed in Trieste and fabricated at FBK, with an active area of 10 mm super(2) and a thickness of 450 mu m. The aforementioned detector has an anode current of about 180 pA at +22degreesC. A minimum Equivalent Noise Charge (ENC) of 16 electrons r.m.s. at 3.0 mu s shaping time and -30degreesC has been demonstrated with a total measured power consumption of 482 mu W.
Low-noise, position-sensitive Silicon Drift Detectors (SDDs) are particularly useful for experiments in which a good energy resolution combined with a large sensitive area is required, as in the case ...of X-ray astronomy space missions and medical applications. This paper presents the experimental characterization of VEGA, a custom Application Specific Integrated Circuit (ASIC) used as the front-end electronics for XDXL-2, a large-area (30.5 cm super(2)) SDD prototype. The ASICs were integrated on a specifically developed PCB hosting also the detector. Results on the ASIC noise performances, both stand-alone and bonded to the large area SDD, are presented and discussed.
SESAME (Synchrotron-light for Experimental Science and Application in the Middle East) is a “third-generation” synchrotron light source. The Middle East’s first major international research centre, ...established as cooperative venture by the scientists and governments of the region, is situated in Jordan. On the basis of the agreement signed between INFN and SESAME, our collaboration has designed and is building a Fluorescence Detector System based on 64 SDDs, each having a 9 mm2 non-collimated sensitive area, realized with eight monolithic arrays for a total collimated sensitive area of 499 mm2. The instrument will be used at the beamline dedicated to x-ray absorption spectroscopy in the energy range 3–30 keV with the capability of reaching a maximum counting rate of at least 3.2 Mcps. The energy resolution required for this application is below 150 eV FWHM @5.9 keV. We plan to have the system completely operative by July 2018. We report on the main building blocks of this system, dedicated to SESAME, and describe the experimental performances measured in the lab and on the XAFS beamline of ELETTRA Sincrotrone Trieste, Italy. In the very first tests the system was successfully operated up to 8 Mcounts/s. The energy resolution below 150 eV @5.9 keV was measured using a 1.6μs peaking time with the detector cooled to 10 °C.
•Novel spectroscopic system for XAFS beamlines features 64 SDDs.•Each SDD has a 9 mm2 non-collimated sensitive area.•The energy resolution is below 150 EV FWHM @5.9 kEV using 1.6 us peaking time.•The Output Count Rate of the complete system results in 8 Mcounts/s.
A Silicon Drift Detector with 3×3 mm2 sensitive area was designed by INFN of Trieste and built by FBK-Trento. It represents a single-pixel precursor of a monolithic matrix of multipixel Silicon Drift ...Detectors and, at the same time, a model of one cell Fluorescence Detector System (XAFS) for SESAME. The point-by-point mapping tests of the detector were carried out in the X-ray facilities at INAF-IAPS in Rome, equipped with a motorized two-axis micrometric positioning system. High precision characterization of this detector was done with a radioactive 55Fe source and a collimated Ti X-ray tube equipped with a Bragg crystal monocromator.
The mapping in different positions and bias condition was specifically-aimed to the detailed analysis of the charge collection efficiency at the edge of the detector. The result is important to understand and verify the aspects related to the collection of the signal with respect to the position of interactions of the photons, especially in consideration of the new design and development of monolithic multipixel detectors.
•High precision mapping of single-pixel Silicon Drift Detector.•The point by point mapping test allows to verify the charge collection.•The mapping is way to verify the efficiency at the edge of the detector.•Four different bias conditions are used for the measurements.•The mapping fosters the progress in the design and development of new detectors.
An Application Specific Integrated Circuit (ASIC) designed as front-end electronics for large area monolithic Silicon Drift Detectors (SDD) read-out has been developed and tested. The challenging ...framework of this project is the read-out of the large-area SDD detectors to be used for X-ray astronomy space missions and medical applications. Due to the inherent low noise of the SDD, these detectors are able to find application in payloads where instruments capable of good energy resolution combined with position resolution and large area are needed. The ASIC has been tested with a SDD prototype having a sensitive area of 4.35×7.02 cm 2 . The SDD was designed to test both the spectroscopic and imaging performance with different anode pitches (967 μm and 147 μm, respectively) being able to fulfill stringent constraints on low-noise (<; 19 erms and <; 15 er.m.s., respectively) and low-power (<; 0.65 mW/ch). The ASIC prototypes were integrated on specially developed high technology PCB hosting also the SDD. Results of the tests on the ASIC, both stand alone and when connected to the detector, are presented in this work.
Mixed-signal ASICs are essential for reading out large X-ray spectroscopic detectors in different fields, including space and medical applications. The pixels size reduction and the detector area ...increase in the newest instruments make the design of the read-out ASIC extremely challenging. Indeed, a large number of channels including low-noise front-end circuits, ADCs, and back-end digital circuits have to coexist on the same chip. In this paper we discuss the challenges of designing ASICs for large area X-ray detectors, using two actual examples: StarX32 and VEGA.
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