A fully integrated pulsed reset charge-sensitive amplifier (CSA) optimized for low-capacitance (<; 100 fF) radiation detectors was developed on a 0.35-μm low-noise CMOS technology. The CSA was successfully tested with a collimated 10-mm ² silicon drift detector (SDD) and extensively characterized. The experimental setup and the achieved spectrometry results with SDD are described for triangular and trapezoidal shaping filters with peaking times ranging from t _peak =0.1-12.8 μs at an operating temperature of -35 °C. With a minimum equivalent noise charge (ENC) of 3.4 electrons rms measured at tpeak

The ORION chipset, a full-custom multichip readout and processing electronics for the X- $\gamma $ -ray imaging spectrometer (XGIS) on-board the transient high-energy sky and early universe surveyor (THESEUS) space mission, is presented. The XGIS detection plane is arranged in a matrix of 10 $\times $ 10 detection modules, each one composed of 64 CsI(Tl) scintillation bars (4.5 mm $\times $ 4.5 mm $\times $ 30 mm) optically coupled at the top and bottom ends to two 8 $\times $ 8 monolithic silicon drift detector (SDD) matrices. The top SDD, exposed to the X-ray entrance window, performs the double function of low-energy X-ray detection as well as scintillator’s readout, together with the bottom SDD, providing detection and spectroscopic energy range from 2 keV up to 20 MeV. The need to achieve a high-energy resolution, as well as a high sensitive area on the detection plane, led to the development of a chipset organized to have a minimum-area analog readout chip placed in close proximity of the SDD (ORION-FE) and a mixed-signal back-end (ORION-BE) placed a few centimeters further on the back-end board for the additional signal processing and digitization. The multichip readout electronics integrates two dedicated analog processors for low-energy photons up to 30 keV (X-processor) and high-energy photons up to 5 MeV ( $\gamma $ -processor), allowing a spectroscopy-grade resolution in the 4 decades energy band (2 keV–20 MeV) of the XGIS, with a simulated power consumption of 1.55 mW/pixel. The ORION prototype was bonded to two ~25 mm ² SDDs, and extensively characterized in terms of pulse shaping, pulse discrimination, and stretching functionality, as well as linearity, dynamic range, and spectroscopic resolution. An optimum equivalent noise charge (ENC) at −20 °C of 24.3 el. r.m.s. on the X-channel [212 eV full-width at half-maximum (FWHM) on Si], and 39.6 el. r.m.s. on the $\gamma $ -channel [3.7 keV FWHM on CsI(Tl)] has been recorded.

X-ray absorption fine-structure (XAFS) spectroscopy can assess the chemical speciation of the elements providing their coordination and oxidation state, information generally hidden to other techniques. In the case of trace elements, achieving a good quality XAFS signal poses several challenges, as it requires high photon flux, counting statistics and detector linearity. Here, a new multi-element X-ray fluorescence detector is presented, specifically designed to probe the chemical speciation of trace 3d elements down to the p.p.m. range. The potentialities of the detector are presented through a case study: the speciation of ultra-diluted elements (Fe, Mn and Cr) in geological rocks from a calcareous formation related to the dispersal processes from Ontong (Java) volcanism (mid-Cretaceous). Trace-elements speciation is crucial in evaluating the impact of geogenic and anthropogenic harmful metals on the environment, and to evaluate the risks to human health and ecosystems. These results show that the new detector is suitable for collecting spectra of 3d elements in trace amounts in a calcareous matrix. The data quality is high enough that quantitative data analysis could be performed to determine their chemical speciation.

Advanced scientific and industrial applications based on X and γ ray spectroscopic imaging need systems able to handle high incoming radiation flux (>1 Mcount/s) and therefore requiring processing of radiation detectors signals in less than 1 μs. The design and realization of very fast systems with high spatial and energy resolution still presents a complex challenge and it is object of the most recent research worldwide. Since room temperature operation and high absorption efficiency (up to 100 keV of photon energy) are required for many applications, in addition to high energy resolution, CdTe or CdZnTe detectors are the main choice for the task. In this framework we have developed a research grade spectroscopic system based on a pixel CdTe detector coupled to an ultra-low noise custom charge preamplifier. The detector is 1 mm thick with 0.75 mm×0.75 mm pixels with Schottky junction; the front-end electronics is SIRIO-6, a CMOS charge preamplifier specifically designed to have ultra-low noise and fast response. The goal of this work is to study the spectroscopic capability of a CdTe pixel detectors, suitable for spectroscopic imaging, at very short signal processing times. Deep sub-microsecond X-γ ray spectroscopy has been successfully accomplished using a trapezoidal pulse shaping with 50 ns flat-top and peaking times ranging from 1 μs down to 50 ns. At room temperature, intrinsic energy resolutions (pulser FWHM) from 205 eV (19.6 electrons rms) at 1 μs to 392 eV (37.6 electrons rms) at 50 ns have been obtained and the FWHMs of the 241Am 59.54 keV line from 472 eV at 1 μs to 617 eV at 50 ns peaking time have been measured, therefore verifying the system capability to reach high energy resolution even at such short signal processing times. The effects of very short signal processing times on the electronic noise, ballistic deficit and system linearity have been measured and discussed.

ALTAIR is an Application Specific Integrated Circuit (ASIC) developed for the readout of CdTe/CdZnTe detectors for X-γ ray spectroscopic imaging. ALTAIR is composed of 16 channels with analog and mixed-signal sections specifically designed for high energy resolution and high-rate applications with the constraints of a low power consumption and operation at room temperature. The ASIC has three selectable ranges for input charge signals covering photon energies up to 90 keV, 160 keV or 300 keV, which allow to optimize the signal to noise ratio under different experimental conditions. Eight peaking times of the pulse shaper are selectable from 200 ns up to 2.3 μs. ALTAIR includes a 180 bits register and an integrated SPI interface to configure the signal processing parameters globally or independently for each channel. The power consumption is 950 μW/channel or 1.35 mW/channel for single ended or differential output versions, respectively. A minimum Equivalent Noise Charge (ENC) of 37 electrons rms (386 eV FWHM in CdTe) has been measured at 500 ns peaking time and 90 keV energy range. With a CdTe pixel detector connected to ALTAIR and operated at +24°C, a pulser FWHM of 1.7 keV (160 el. rms) and 1.9 keV FWHM on 59.54 keV line of 241Am have been achieved at a peaking time of 500 ns.