- 标题
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Digital pulse timing with semiconductor gamma-ray detectors using a wavelet transform technique
摘要： Obtaining precise timing information from semiconductor gamma-ray detectors is of great interest for a variety of applications such as high-resolution positron emission tomography. However, pulse timing with these detectors through the common constant-fraction discrimination (CFD) method is strongly affected by the time-walk error that results from the inherent variations in the shape of the detectors’ pulses. This paper reports on the use of the wavelet transform for minimizing the time-walk error in digital CFD pulse timing with semiconductor gamma-ray detectors. The details of the method are described, and the experimental results with a 1 mm thick CdTe detector are shown. It is demonstrated that, by using the Haar wavelet transform of the digitized preampli?er pulses, the original tailed time spectrum of the detector with a time resolution of 8.22 ± 0.12 ns at full-width at half-maximum (FWHM) in the energy range of 300-550 keV improves to a symmetric time spectrum with a time resolution of 3.39 ± 0.02 ns (FWHM).
关键词： wavelet transform,time-walk error,CdTe detector,digital pulse timing,semiconductor gamma-ray detectors
更新于2025-09-23 15:21:21
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Characterization of Si and SiC detectors for laser-generated plasma monitoring in short wavelength range
摘要： Silicon carbide detectors were employed to characterize the plasma produced by laser interaction with a double stream gas-pu? target source. A 10 Hz repetition rate Nd:YAG laser (1064 nm wavelength, 0.69 J pulse energy and 3 ns pulse duration) was employed to irradiate di?erent gas-pu? targets (Argon, Xenon and Sulfur hexa?uoride), at di?erent pressures (1–10 bar), emitting plasma radiation in di?erent wavelength ranges (ultraviolet, extreme ultraviolet and soft X-rays). The emission produced by the laser radiation was properly ?ltered (employing Titanium, Aluminium, Zirconium and Calcium ?uoride ?lters), to narrow down the broad-band emission of the generated plasma. The SiC detectors’ signals were compared with a calibrated traditional silicon detector evaluating their di?erences, i.e. taking into account the plasma stability, the time trace pro?le and the characteristics of the gas-pu? target source. The obtained results, which will be presented and discussed, allow to improve the geometry and con?guration of the SiC detectors avoiding saturation and charge recombination e?ects and getting a better proportionality to the energy and ?uence of the detected radiations.
关键词： X-ray detectors,Radiation monitoring,Detectors for UV, visible and IR photons,Plasma generation (laser-produced, RF, x ray-produced)
更新于2025-09-23 15:21:01
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[IEEE 2020 International SAUPEC/RobMech/PRASA Conference - Cape Town, South Africa (2020.1.29-2020.1.31)] 2020 International SAUPEC/RobMech/PRASA Conference - Thin film photovoltaic module characterisation based in indoor and outdoor methods
摘要： This paper is the fifth in a series of articles on the basic physics of light yield nonproportionality in scintillators. Here, we compare and contrast the nonproportionality as registered by gamma rays and high-energy electrons. As has been noted in the past, these two types of data have different curve shapes (for plots of the light yield against electron or gamma energy). Herein, we show how the experimental gamma nonproportionality curve can be calculated from the electron response by accounting for the distribution of high energy electrons created by the gamma photon via the photoelectric interaction. Similarly, we measure and model the gamma-induced resolution as a function of energy and compare this data to predictions from our model. The utility of the model is explored using data acquired with the scintillators (Eu), GYGAG(Ce) and CsI(Na).
关键词： Gamma ray detectors,solid scintillation detectors,luminescence
更新于2025-09-23 15:21:01
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[IEEE 2019 8th International Congress on Advanced Applied Informatics (IIAI-AAI) - Toyama, Japan (2019.7.7-2019.7.11)] 2019 8th International Congress on Advanced Applied Informatics (IIAI-AAI) - Phase Type Special-Purpose Computer for Electroholography in Embedded Systems
摘要： This paper is the fifth in a series of articles on the basic physics of light yield nonproportionality in scintillators. Here, we compare and contrast the nonproportionality as registered by gamma rays and high-energy electrons. As has been noted in the past, these two types of data have different curve shapes (for plots of the light yield against electron or gamma energy). Herein, we show how the experimental gamma nonproportionality curve can be calculated from the electron response by accounting for the distribution of high energy electrons created by the gamma photon via the photoelectric interaction. Similarly, we measure and model the gamma-induced resolution as a function of energy and compare this data to predictions from our model. The utility of the model is explored using data acquired with the scintillators (Eu), GYGAG(Ce) and CsI(Na).
关键词： Gamma ray detectors,solid scintillation detectors,luminescence
更新于2025-09-23 15:21:01
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High-selectivity bandpass filter using six pairs of quarter-wavelength coupled lines
摘要： We present a 16-channel readout integrated circuit (ROIC) with nanosecond-resolution time to digital converter (TDC) for pixelated Cadmium Telluride (CdTe) gamma-ray detectors. The pixel array ROIC is the proof of concept of the pixel array readout ASIC for positron-emission tomography (PET) scanner, positron-emission mammography (PEM) scanner, and Compton gamma camera. The electronics of each individual pixel integrates an analog front-end with switchable gain, an analog to digital converter (ADC), configuration registers, and a 4-state digital controller. For every detected photon, the pixel electronics provides the energy deposited in the detector with 10-bit resolution, and a fast trigger signal for time stamp. The ASIC contains the 16-pixel matrix electronics, a digital controller, five global voltage references, a TDC, a temperature sensor, and a band-gap based current reference. The ASIC has been fabricated with TSMC m mixed-signal CMOS technology and occupies an area of mm. The TDC shows a resolution mm of 95.5 ps, a precision of 600 ps at full width half maximum W. In acquisition (FWHM), and a power consumption of mode, the total power consumption of every pixel is W. An equivalent noise charge (ENC) of at maximum gain and negative polarity conditions has been measured at room temperature.
关键词： positron emission tomography,low-power electronics,semiconductor radiation detectors,application specific integrated circuits,gamma-ray detectors,Analog-digital conversion,energy resolution
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Doped Layer Characterization Using Accurate Optical Modelling of Mid-Infrared Spectrometry
摘要： We present a 16-channel readout integrated circuit (ROIC) with nanosecond-resolution time to digital converter (TDC) for pixelated Cadmium Telluride (CdTe) gamma-ray detectors. The pixel array ROIC is the proof of concept of the pixel array readout ASIC for positron-emission tomography (PET) scanner, positron-emission mammography (PEM) scanner, and Compton gamma camera. The electronics of each individual pixel integrates an analog front-end with switchable gain, an analog to digital converter (ADC), con?guration registers, and a 4-state digital controller. For every detected photon, the pixel electronics provides the energy deposited in the detector with 10-bit resolution, and a fast trigger signal for time stamp. The ASIC contains the 16-pixel matrix electronics, a digital controller, ?ve global voltage references, a TDC, a temperature sensor, and a band-gap based current reference. The ASIC has been fabricated with TSMC m mixed-signal CMOS technology and occupies an area of mm. The TDC shows a resolution mm of 95.5 ps, a precision of 600 ps at full width half maximum W. In acquisition (FWHM), and a power consumption of mode, the total power consumption of every pixel is W. An equivalent noise charge (ENC) of at maximum gain and negative polarity conditions has been measured at room temperature.
关键词： positron emission tomography,low-power electronics,application speci?c integrated circuits,semiconductor radiation detectors,gamma-ray detectors,Analog-digital conversion,energy resolution
更新于2025-09-23 15:21:01
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Timepix in LEO Orbit onboard the VZLUSAT-1 Nanosatellite: 1-year of Space Radiation Dosimetry Measurements
摘要： The VZLUSAT-1 satellite, the first Czech CubeSat, was successfully launched on June 23, 2017, to a 510 km Sun-synchronous low-Earth orbit. It carries several scientific payloads including a Timepix detector as focal plane imager for the X-Ray telescope onboard. The Timepix detector contributes significantly to the satellite data collection, with more than 25 000 sampling acquisitions in the first year of deployment. Despite limitations of the satellite attitude control system, necessary for capturing X-Ray images of the Sun, the Timepix detector allows measuring the space radiation environment along the satellite orbit. As of September 2018, we conducted 33 whole-Earth mappings, recording radiation doses around the planet. Further, we show data from scans of the South Atlantic Anomaly and polar radiation horns, where the location and acquisition time were tailored to minimize event pile-up and particle track overlap. Since October 2017, the optics segment of the onboard X-Ray telescope was deployed, which exposed the Timepix detector unshielded to free open space. This change produced entirely new observations namely of low energy charged particles and a significant increase of measured particle flux. We also registered the effects of exposing the sensor to direct intense sunlight. We will summarize on the actual performance of the custom readout interface, which exceeds expectations in the constrained environment of the low-cost and low-powered CubeSat nanosatellite.
关键词： Particle detectors,On-board space electronics,X-ray detectors and telescopes,Space instrumentation
更新于2025-09-23 15:21:01
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Ion, electron and laser beams for Cultural Heritage investigations by Czech-Italian collaboration
摘要： An overview of physical investigations of cultural heritage samples using ion and laser beams performed in the frame of the international collaboration between the University of Messina (Italy) and the Nuclear Physics Institute-ASCR (Czech Republic) is presented. Solid samples are analysed in high vacuum using particle induced X-ray emission, Rutherford backscattering spectrometry, elastic recoil detection analysis, prompt γ activation analysis, nuclear reaction analysis, laser ablation, mass spectrometry, scanning electron microscopy, and many more. The elemental composition of the sample, the trace elements, the depth pro?les, the morphology and the comparison between samples and references are reported. Both electron and ion microbeams are employed to have details of the spatial distribution maps of elements of interest.
关键词： Mass spectrometers,X-ray detectors,X-ray ?uorescence (XRF) systems
更新于2025-09-23 15:21:01
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Operation and performance of the JUNGFRAU photon detector during first FEL and synchrotron experiments
摘要： JUNGFRAU is a hybrid pixel photon detector developed at the Paul Scherrer Institut for free electron laser (FEL) and synchrotron applications. A charge integrating detector, JUNGFRAU features three automatically switching gains per pixel which adjust the amplification factor to the amount of deposited charge. This enables single photon sensitivity, while ensuring a dynamic range over four orders of magnitude. Each detector module consists of eight 256 × 256 pixel ASICs bump-bonded to a single 320 μm thick silicon sensor, resulting in half a million pixels of 75 μm pitch arranged in 1024 × 512 arrays for a sensitive area of approximately 8 × 4 cm2. Modules can be combined in various configurations to produce larger systems. These proceedings present the required steps, both operational and in terms of data processing, necessary to perform experiments with the JUNGFRAU detector. This includes the calculation and application of pedestal and gain corrections and the geometric arrangement of the recorded image. Examples of these techniques in action will be presented from the first experiments performed with JUNGFRAU detectors; the pilot experiment of the SwissFEL Bernina beamline and proof-of-principle macromolecular crystallography measurements from the X06SA beamline of the Swiss Light Source. Successful operation and data processing methods from FEL and synchrotron facilities will be compared and contrasted, and experience of overcoming challenges in the two scenarios will be shared. Finally, the capability of JUNGFRAU for FEL and synchrotron applications will be demonstrated.
关键词： Instrumentation for synchrotron radiation accelerators,X-ray detectors,Instrumentation for FEL
更新于2025-09-23 15:21:01
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Characterization of noise and efficiency of the Pixirad-1/Pixie-III CdTe X-ray imaging detector
摘要： Thanks to their high detection e?ciency and low intrinsic noise, direct conversion X-ray Photon Counting Detectors (XPCDs) are particularly suitable for low dose imaging applications such as mammography. The photon counting technology can implement also two or more acquisition thresholds to perform single-shot spectral imaging with one polychromatic source. However, XPCDs with thick high Z crystal sensor and small pixel size are a?ected by the charge sharing e?ect. This issue can induce multiple counts from a single interaction reducing both spectral and spatial resolutions. In a pure counting mode, multiple counts from charge sharing can be partially or totally removed by increasing the acquisition threshold at the cost of a loss of e?ciency. Thus, the performances of XPCDs can be threshold-dependent. New generation XPCDs implement solutions to cope with charge sharing issue. If the charge sharing is properly corrected, no multiple counts are recorded and the performances (detection e?ciency, spectral and spatial resolutions) of the acquisition system are expected to be independent from the acquisition threshold. This work presents a study of a Pixirad-1 detection system based on a CdTe Schottky sensor and PIXIE-III readout system. This chip can be con?gured in three di?erent operation modes, two of which implement solutions to remove multiple counts. Using monochromatic radiation, the performances of these di?erent operation modes have been compared trough a measure of the integral spectra and the Signal to Noise Ratio (SNR) as function of the acquisition threshold.
关键词： Hybrid detectors,X-ray detectors,Pixelated detectors and associated VLSI electronics
更新于2025-09-23 15:19:57