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- 摘要
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- 实验方案
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MeV photon imaging with robotic sample positioning at a research reactor
摘要： This paper summarizes the development and demonstration of an X-ray and gamma-ray radiography capability using a TRIGA MARK-II reactor. Photons are a combination of Bremsstrahlung X-rays and gamma rays from fission and radioactive decay. The energy spectrum of the facility was analyzed with a NaI(Tl) scintillator detector. A digital X-ray camera for use with MeV-range photons images a duplex wire-type penetrameter to analyze unsharpness and spatial resolution. An industrial manipulator precisely positions the sample, which allows objects to have larger dimensions than the detector’s field-of-view. Future work includes performing computed tomography to create 3-dimensional representations of objects.
关键词： Nuclear research reactor,Gamma,X-ray,Non-destructive testing,Radiation imaging,Robotics
更新于2025-09-23 15:21:01
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Polymers and Electromagnetic Radiation || Front Matter
摘要： This book concentrates on the interaction of electromagnetic waves with polymers and deals only exceptionally with particle radiation. Electromagnetic waves comprise a very broad range of frequencies that extends over more than 20 orders of magnitude from the radiofrequency region up to the region of hard c-rays emitted from radionuclides or being part of the cosmic rays.
关键词： microwave,radiofrequency,visible light,infrared radiation,gamma rays,polymers,electromagnetic waves,interaction,X-rays,ultraviolet light
更新于2025-09-23 15:21:01
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Fabrication of Milk Fat Sensor based on Plastic Optical Fiber
摘要： The research about milk fat content based on plastic optical fiber sensor using gamma and spiral spring without cladding configurations has been reported. LED light transmitted through the plastic optical fiber to be received by the phototransistor. Changes in milk fat content affect the light intensity received by the phototransistor. Sensor output voltage amplified by a differential amplifier and then the analog signal converted into the digital signal by the Arduino Uno microcontroller furthermore, the output voltage read on a computer. The milk fat content sample with a percentage of 0.773 % to 4.473 % affect the propagation of light in the core of plastic optical fiber results in power losses that occur so that the light intensity decreases and the output voltage measured becomes smaller. The results showed that the higher the milk fat content, the sensor output voltage decreases. The best measurements obtained on the spiral spring configuration with 4 windings produce value range 0.044 V, sensitivity 11.887 mV/%, and a resolution of 0.084 %. This method is effective as well as efficiently used as milk fat sensor because it has good sensitivity and resolution.
关键词： spiral spring configuration,sensitivity,resolution,gamma configuration,milk fat sensor,plastic optical fiber
更新于2025-09-23 15:19:57
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[IEEE 2019 22nd European Microelectronics and Packaging Conference & Exhibition (EMPC) - Pisa, Italy (2019.9.16-2019.9.19)] 2019 22nd European Microelectronics and Packaging Conference & Exhibition (EMPC) - Glass Wafer Level Packaging Enabled by Laser Induced Deep Etching of Closed Cavities
摘要： Segmented gamma scanning (SGS) and tomographic gamma scanning (TGS) are two traditional detection techniques for low and intermediate level radioactive waste drum. This paper proposes one detection method named semi-tomographic gamma scanning (STGS) to avoid the poor detection accuracy of SGS and shorten detection time of TGS. This method and its algorithm synthesize the principles of SGS and TGS. In this method, each segment is divided into annual voxels and tomography is used in the radiation reconstruction. The accuracy of STGS is veri?ed by experiments and simulations simultaneously for the 208 liter standard waste drums which contains three types of nuclides. The cases of point source or multi-point sources, uniform or nonuniform materials are employed for comparison. The results show that STGS exhibits a large improvement in the detection performance, and the reconstruction error and statistical bias are reduced by one quarter to one third or less for most cases if compared with SGS.
关键词： radioactive waste,semi-tomographic gamma scanning (STGS),Non-destructive assay
更新于2025-09-23 15:19:57
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[IEEE 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Guangzhou, China (2019.5.19-2019.5.22)] 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Surface Waveguide Leaky-wave Antenna for Single-Side Beam Scanning
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： gamma-ray detectors,low-power electronics,Analog-digital conversion,semiconductor radiation detectors,application specific integrated circuits,positron emission tomography,energy resolution
更新于2025-09-23 15:19:57
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Fast and efficient detection of 511 keV photons using Cherenkov light in PbF <sub/>2</sub> crystal, coupled to a MCP-PMT and SAMPIC digitization module
摘要： We study the possibility to use the Cherenkov light for the e?cient detection of 511 keV photons with the goal to use it in TOF-PET. We designed and tested two detection modules consisting of PbF2 crystals attached to Planacon MCP-PMT XP85012. Ampli?ed PMT signals are digitized by the SAMPIC module with high readout rate, up to 105 events/s, and a negligible contribution to the time resolution, below 20 ps (FWHM). We developed a fast 2D scanning system to calibrate the PMT time response and studied in details the timing characteristics of the Planacon PMT. Using a radioactive 22Na source we measured a detection e?ciency of 24% for 511 keV photons in a 10 mm thick crystal and a coincidence resolving time of 280 ps. We analyzed the main factors limiting the time resolution of the large-surface detection module and proposed solutions to improve it, which will be tested in our future project.
关键词： Photon detectors for UV, visible and IR photons (vacuum) (photomultipliers, HPDs, others),Cherenkov and transition radiation,Gamma camera, SPECT, PET PET/CT, coronary CT angiography (CTA)
更新于2025-09-23 15:19:57
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CMOS-coupled NaI scintillation detector for gamma decay measurements
摘要： We report an all-solid-state gamma-ray scintillation detector comprised of a NaI(Tl) crystal and a scientific-grade CMOS camera. After calibration, this detector exhibits excellent linearity over more than three decades of activity levels ranging from 10 mCi to 400 nCi. Because the detector is not counting pulses, dead-time correction is not required. Compared to systems that use a photomultiplier tube, this detector has similar sensitivity and noise characteristics on short time scales. On longer time scales, we measure drifts of a few percent over several days, which can be accommodated through regular calibration. Using this detector, we observe that when high activity sources are brought into close proximity to the NaI crystal, several minutes are required for the measured signal to achieve a steady state.
关键词： gamma-ray scintillation detector,dead-time correction,photomultiplier tube,NaI(Tl) crystal,CMOS camera
更新于2025-09-23 15:19:57
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Characteristics of Si and SiC detectors at registration of Xe ions
摘要： The results of an investigation of silicon (Si) and silicon carbide (SiC) detectors when irradiated with a beam of Xenon (Xe) ions are presented. The irradiation was carried out at the IC-100 cyclotron, JINR, Dubna. The effect of the Pulse Height Defect (PHD) in registering Xe ions with energies 165, 82 and 45 MeV is shown to be twice as large for SiC detectors as that for Si detectors. It is also shown that degradation of SiC detectors irradiated with heavy Xe ions occurs at doses an order of magnitude greater than for Si detectors. The measurement method described, including continuous detector calibration by alpha-particles, makes it possible to simultaneously control the characteristics of detectors during irradiation and determine the energy of a beam of ions.
关键词： Radiation-hard detectors,Heavy-ion detectors,Solid state detectors,Gamma detectors (scintillators, CZT, HPG, HgI etc)
更新于2025-09-23 15:19:57
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Fast non-local means noise reduction algorithm with acceleration function for improvement of image quality in gamma camera system: a phantom study
摘要： Gamma-ray images generally suffer from a lot of noise because of low photon detection in the gamma camera system. The purpose of this study is to improve the image quality in gamma-ray images using a gamma camera system with a fast nonlocal means (FNLM) noise reduction algorithm with an acceleration function. The designed FNLM algorithm is based on local region considerations, including the Euclidean distance in the gamma-ray image and use of the encoded information. To evaluate the noise characteristics, the normalized noise power spectrum (NNPS), contrast-to-noise ratio (CNR), and coefficient of variation (COV) were used. According to the NNPS result, the lowest values can be obtained using the FNLM noise reduction algorithm. In addition, when the conventional methods and the FNLM noise reduction algorithm were compared, the average CNR and COV using the proposed algorithm were approximately 2.23 and 7.95 times better than those of the noisy image, respectively. In particular, the image-processing time of the FNLM noise reduction algorithm can achieve the fastest time compared with conventional noise reduction methods. The results of the image qualities related to noise characteristics demonstrated the superiority of the proposed FNLM noise reduction algorithm in a gamma camera system.
关键词： Medical application,Noise reduction algorithm,Evaluation of image quality,Total variation noise reduction method,Gamma camera system
更新于2025-09-23 15:19:57
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A radioxenon detection system using PIPS and CZT
摘要： This paper introduces and describes the initial characterizations of a prototype beta-gamma coincidence detection system that utilizes a PIPSBox and two coplanar CdZnTe detectors for atmospheric radioxenon identification and nuclear test ban treaty verification. Coincidences between four independent detecting bodies are identified in real time via a custom coincidence module implemented in a field-programmable gate array. The system is compact, maintains simple readout electronics, and provides high resolution radiation detection at room temperature operation. Preliminary measurements using 137Cs and 131mXe were conducted to optimize various system parameters to achieve optimal energy resolution of key spectral features. The purpose of this research was to explore the utility of these materials and methods for radioxenon monitoring in the International Monitoring System.
关键词： Radioxenon,CTBTO,Nuclear explosion monitoring,Beta-gamma coincidence,PIPSBox
更新于2025-09-23 15:19:57