117,463 research outputs found
High-Z Materials for X-ray Detection: Material Properties and Characterization Techniques
No full textThis book will provide readers with a good overview of some of most recent advances in the field of High-Z materials. There will be a good mixture of general chapters in both technology and applications in opto-electronics, X-ray detection and emerging optoelectronics applications. The book will have an in-depth review of the research topics from world-leading specialists in the field
Performance enhancements of compound semiconductor radiation detectors using digital pulse processing techniques
No full textThe potential benefits of using compound semiconductors for X-ray and gamma ray spectroscopy are already well known. Radiation detectors based on high atomic number and wide band gap compound semiconductors show high detection efficiency and good spectroscopic performance even at room temperature. Despite these appealing properties, incomplete charge collection is a critical issue. Generally, incomplete charge collection, mainly due to the poor transport properties of the holes, produces energy resolution worsening and the well known hole tailing in the measured spectra. In this work, we present a digital pulse processing (DPP) system for high resolution spectroscopy with compound semiconductor radiation detectors. The DPP method, implemented on a PC platform, performs a height and shape analysis of the detector pulses (preamplifier output pulses), digitized by a 14-bit, 100 MHz ADC. Fast and slow shaping, automatic pole-zero adjustment, baseline restoration and pile-up rejection allow precise pulse height measurements both at low and high counting rate environments. Pulse shape analysis techniques (pulse shape discrimination, linear and nonlinear pulse shape corrections) to compensate for incomplete charge collection were also implemented. The results of spectroscopic measurements on a planar CdTe detector show the high potentialities of the system, obtaining low tailing in the measured spectra and energy resolution quite close to the theoretical limit. High-rate measurements (up to 820 kcps) exhibit the excellent performance of the pulse height analysis and the benefits of pulse shape techniques for peak pile-up reduction in the measured spectra. This work was carried out in the framework of the development of portable X-ray spectrometers for both laboratory research and medical applications
A digital approach for real time high-rate high-resolution radiation measurements
No full textModern spectrometers are currently developed by using digital pulse processing (DPP) systems, showing
several advantages over traditional analog electronics. The aim of this work is to present digital
strategies, in a time domain, for the development of real time high-rate high-resolution spectrometers.
We propose a digital method, based on the single delay line (SDL) shaping technique, able to perform
multi-parameter analysis with high performance even at high photon counting rates. A robust pulse
shape and height analysis (PSHA), applied on single isolated time windows of the detector output
waveforms, is presented.
The potentialities of the proposed strategy are highlighted through both theoretical and experimental
approaches. To strengthen our approach, the implementation of the method on a real-time
system together with some experimental results are presented. X-ray spectra measurements with a
semiconductor detector are performed both at low and high photon counting rates (up to 1.1 Mcps)
Digital Techniques for High-Rate High-Resolution Radiation Measurements
No full textDigital pulse processing (DPP) techniques are increasingly used in the development of modern spectroscopic systems. DPP systems, based on direct digitizing and processing of detector signals (preamplifier output signals), ensure higher flexibility, stability, lower dead time, higher throughput and better energy resolution than traditional pulse processing systems. In this work, we present our progress in the development of DPP systems for high-rate high-resolution radiation measurements. An innovative digital system, able to perform multi-parameter analysis (input counting rate, pulse height, pulse shape, event arrival time, etc.) even at high photon counting rates is presented. Experimental results with CdTe detectors (planar and pixel detectors) are presented, at both low and high counting rate environments (up to 2 Mcps)
High-rate dead-time corrections in a general purpose digital pulse processing system
No full textDead-time losses are well recognized and studied drawbacks in counting and spectroscopic systems. In this work the abilities on dead-time correction of a real-time digital pulse processing (DPP) system for high-rate high-resolution radiation measurements are presented. The DPP system, through a fast and slow analysis of the output waveform from radiation detectors, is able to perform multi-parameter analysis (arrival time, pulse width, pulse height, pulse shape, etc.) at high input counting rates (ICRs), allowing accurate counting loss corrections even for variable or transient radiations. The fast analysis is used to obtain both the ICR and energy spectra with high throughput, while the slow analysis is used to obtain high-resolution energy spectra. A complete characterization of the counting capabilities, through both theoretical and experimental approaches, was performed. The dead-time modeling, the throughput curves, the experimental time-interval distributions (TIDs) and the counting uncertainty of the recorded events of both the fast and the slow channels, measured with a planar CdTe (cadmium telluride) detector, will be presented. The throughput formula of a series of two types of dead-times is also derived. The results of dead-time corrections, performed through different methods, will be reported and discussed, pointing out the error on ICR estimation and the simplicity of the procedure. Accurate ICR estimations (nonlinearity < 0.5%) were performed by using the time widths and the TIDs (using 10-14;ns time bin width) of the detected pulses up to 2.2-14;Mcps. The digital system allows, after a simple parameter setting, different and sophisticated procedures for dead-time correction, traditionally implemented in complex/dedicated systems and time-consuming set-ups
CdTe Detectors
No full textCadmium telluride (CdTe) compound semiconductors for x-ray detectors have experienced a rather rapid development in the last few years, due to their appealing performance. In this chapter we review the physical properties of semiconductor detectors for x-ray and γ ray spectroscopy. In particular, we focus on compound semiconductor detectors. We also review the principles of operation of both the semiconductor detectors and the electronic chains, with special emphasis on the digital techniques. CdTe detectors’ characteristics and performance enhancements are discussed in depth. Finally, we present some original results on CdTe detectors for medical applications
Accelerated Tests on Si and SiC Power Transistors with Thermal, Fast and Ultra-Fast Neutrons
No full textNeutron test campaigns on silicon (Si) and silicon carbide (SiC) power MOSFETs and IGBTs were conducted at the TRIGA (Training, Research, Isotopes, General Atomics) Mark II (Pavia, Italy) nuclear reactor and ChipIr-ISIS Neutron and Muon Source (Didcot, U.K.) facility. About 2000 power transistors made by STMicroelectronics were tested in all the experiments. Tests with thermal and fast neutrons (up to about 10 MeV) at the TRIGA Mark II reactor showed that single-event burnout (SEB) failures only occurred at voltages close to the rated drain-source voltage. Thermal neutrons did not induce SEB, nor degradation in the electrical parameters of the devices. SEB failures during testing at ChipIr with ultra-fast neutrons (1-800 MeV) were evaluated in terms of failure in time (FIT) versus derating voltage curves according to the JEP151 procedure of the Joint Electron Device Engineering Council (JEDEC). These curves, even if scaled with die size and avalanche voltage, were strongly linked to the technological processes of the devices, although a common trend was observed that highlighted commonalities among the failures of different types of MOSFETs. In both experiments, we observed only SEB failures without single-event gate rupture (SEGR) during the tests. None of the power devices that survived the neutron tests were degraded in their electrical performances. A study of the worst-case bias condition (gate and/or drain) during irradiation was performed
Digital Pulse-Processing Techniques for X-Ray and Gamma-Ray Semiconductor Detectors
No full textOver the last decade, digital pulse-processing (DPP) electronics have been widely
proposed and used for new generation x- and gamma-ray spectrometers. DPP systems,
based on direct digitizing and processing of detector signals, lead to better
results than the traditional analog pulse-processing electronics in terms of stability,
flexibility, reproducibility, energy resolution, throughput, and dead time. In this
chapter, we will review the principles of operation of conventional analog electronic
chains for x- and gamma-ray semiconductor detectors, with special emphasis on the
benefits of the digital approach. The characteristics of a new real-time DPP system,
developed by our group, are discussed in depth. Finally, we present some original
results on cadmium telluride (CdTe) and germanium (Ge) detectors, highlighting the
excellent performance of the DPP system both at low and high counting rate environments
(up to 1.1 Mcps)
Digital techniques for high-rate high-resolution radiation measurements
No full textDigital pulse processing (DPP) techniques are increasingly used in the development of modern spectroscopic systems. DPP systems, based on direct digitizing and processing of detector signals (preamplifier output signals), ensure higher flexibility, stability, lower dead time, higher throughput and better energy resolution than traditional pulse processing systems. In this work, we present our progress in the development of DPP systems for high-rate high-resolution radiation measurements. An innovative digital system, able to perform multi-parameter analysis (input counting rate, pulse height, pulse shape, event arrival time, etc.) even at high photon counting rates is presented. Experimental results with CdTe detectors (planar and pixel detectors) are presented, at both low and high counting rate environments (up to 2 Mcps)
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