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This paper aims at exploring and validating the adoption of standard fabrication processes for the realization of CMOS active pixel sensors, for particle detection purposes. The goal is to implement a single-chip, complete radiation sensor system, including on a CMOS integrated circuit the sensitive devices, read-out and signal processing circuits. A prototype chip (RAPS01) based on these principles has been already fabricated, and a chip characterization has been carried out; in particular, the evaluation of the sensitivity of the sensor response on the actual operating conditions was estimated, as well as the response uniformity. Optimization and tailoring of the sensor structures for High Energy Physics applications are being evaluated in the design of the next generation chip (RAPS02). Basic features of the new chip includes digitally configurable readout and multi-mode access (i.e., either sparse of line-scan readout). [ABSTRACT FROM AUTHOR]

As a continuation of our digital X-ray imaging sensor R&D, we have developed a cost-effective, portable, digital radiographic system based on a CMOS image sensor coupled with a fiber optic plate (FOP) and selected conventional scintillators. The imaging system consists of a commercially available CMOS image sensor of 48 μm × 48 μm pixel size and 49.2 mm × 49.3 mm active area, a FOP bundled with several millions of glass fibers of about 6 μm in diameter and 3 mm in thickness, phosphor screens such as Min-R or Lanex series, a readout IC board, a GUI software, and a battery-operated X-ray generator (20-60 kVp up to 1 mA). Here the FOP was incorporated into the imaging system to reduce the performance degradation of the CMOS sensor module caused by irradiation and also to improve image quality. In this paper, we described each imaging component of the fully-integrated portable digital radiographic system in detail, and also presented its performance analysis with experimental measurements and acquired X-ray images in terms of system response with exposure, contrast-to-noise ratio (CNR), modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE). [ABSTRACT FROM AUTHOR]

We present a compact, fully integrated, low power baseline restorer for radiation detector readout ASICs. The proposed circuit has been designed, simulated, and layed out using a 0.35 μm CMOS technology. It features an area occupancy of 90 × 100 μm² and a power consumption of 90 μW for 3.3 V power supplies, which makes it suitable for highly packed multi-channel detector readouts. In the paper the principle of operation of the circuit as well as the results of the simulations are discussed. [ABSTRACT FROM AUTHOR]

We present a CMOS preamplifier-shaper circuit designed to be used with low-noise solid-state detectors, like silicon drift detectors (SDDs), in X-ray Spectroscopy and γ-ray imaging applications. The circuit is composed of a low-noise preamplifier and by a sixth-order semi-Gaussian shaping amplifier with four selectable peaking times from 1.7 μs up to 6 μs. The integrated time constants used for the shaping are implemented by means of a recently proposed "RC" cell. This cell is based on the demagnification of the current flowing in a resistor ft thanks to the use of current mirrors. The particular solution adopted here allows a precise and stable implementation of the desired time constant, for given values of ft and C , and guarantees low-noise performances of the shaping amplifier when used with a cooled SDDs or other solid-state detectors with low leakage current. In this work, the main features of the circuit are first presented. The experimental results obtained with a prototype realized in the 0.35-μm 3.3-V CMOS austriamicrosystems technology are then reported and discussed. The energy resolution measured using the chip with a SDD cooled at -10 °C is 150 eV at 6 keV which corresponds to an electronics noise of 10.8 e-rms. [ABSTRACT FROM AUTHOR]

In this work, we present the extensive analysis of a new class of current-mode shaping amplifiers that can be realized in CMOS or BiCMOS technology. They are suitable for high-resolution spectroscopy, as we have demonstrated in previous works. The proposed topology is suitable to design shaping amplifiers with a wide range of time constants (∼0.1-10 μs) in a very compact scheme. In particular, we show the results of two fourth-order shapers characterized by 500- and 167-ns shaping time, respectively, realized in 0.8-μm BiCMOS technology. The two prototypes were designed in view of the use with Silicon Drift Detectors for X-ray spectroscopy applications. The measured integral nonlinearity is below ±0.1% and the achieved energy resolution at the Mn Kα line (measured with the proposed spectroscopy amplifier with a 5 mm² Peltier-cooled Silicon Drift Detector) is 160 eV full width at half maximum (FWHM) with 500-ns shaping time, comparable to the one obtained with a commercial shaping amplifier with the same time constant. [ABSTRACT FROM AUTHOR]