45 results on '"Daowu, Li"'
Search Results
2. High-sensitivity stereo coded aperture gamma camera for three-dimensional localization of radioactive hotspots
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Yantao Liu, Lei Shuai, Daowu Li, Shuangquan Liu, Yingjie Wang, Wei Zhou, Huan Huang, Xiaoming Wang, Xuanhou Hu, Xiuzuo Liang, Kai Zhuang, Ting Li, Yue Yu, Xin Li, Yi Ding, Yan Zhao, Yiwen Zhang, Zhiming Zhang, Cunfeng Wei, Xianyun Ai, Jipeng Zhang, Xiong Xiao, and Long Wei
- Subjects
Physics ,QC1-999 - Abstract
This work presents a novel stereo coded aperture gamma camera based on four detection modules placed within four quadrants. Each module includes 48 × 48 strips of Bi4Ge3O12 scintillators, 24 × 24 pieces of silicon photomultipliers (SiPMs), and a set of data acquisition circuits. All signals from the SiPMs are individually extracted and finally simplified into 144 outputs to calculate the positions and energies of gamma-rays. Two masks of modified uniformly redundant arrays are fixed in the front of the top-right and bottom-left modules and two anti-masks are fixed in the top-left and bottom-right modules to achieve simultaneous imaging without dual measure. Once the projections of radioactive sources are determined, their source-to-detector distances can be estimated by our new multocular ranging algorithm. A series of lab and field experiments, including flood histogram and energy spectrum testing, field-of-view and angular resolution testing, real-time imaging, long-distance imaging, and ranging ability testing, with different radioactive sources, such as 137Cs, 22Na, 241Am, 60Co, 133Ba, and 75Se, have been completed to evaluate the comprehensive ability of the stereo gamma camera. The results show that the stereo gamma camera has a strong ability for the three-dimensional localization of radioactive sources over long distances with a high image sensitivity. So far, the stereo gamma camera has been successfully used in practical nuclear security and safety tasks although the angular resolution and the ranging algorithm robustness should be more optimized in the future.
- Published
- 2022
- Full Text
- View/download PDF
3. Image reconstruction for the coded aperture system in nuclear safety and security using a Monte Carlo-based system matrix
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Yue Yu, Xiaoli Sun, Zhiming Zhang, Shuangquan Liu, Xiuzuo Liang, Daowu Li, Lei Shuai, Tingting Hu, and Long Wei
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Nuclear and High Energy Physics ,Nuclear Energy and Engineering - Published
- 2023
4. Far-Field 3-D Localization of Radioactive Hotspots via Four-Eyes Stereo Gamma Camera
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Yue Yu, Shuangquan Liu, Zhiming Zhang, Yantao Liu, Xiuzuo Liang, Daowu Li, Lei Shuai, Cunfeng Wei, and Long Wei
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Nuclear and High Energy Physics ,Nuclear Energy and Engineering ,Electrical and Electronic Engineering - Published
- 2022
5. Far field 3D localization of radioactive hot spots using a coded aperture camera
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Shifeng, Sun, Zhiming, Zhang, Lei, Shuai, Daowu, Li, Yingjie, Wang, Yantao, Liu, Xianchao, Huang, Haohui, Tang, Ting, Li, Pei, Chai, Yiwen, Zhang, Wei, Zhou, Mingjie, Yang, Cunfeng, Wei, Chuangxin, Ma, and Long, Wei
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- 2016
- Full Text
- View/download PDF
6. A hybrid coded-aperture and Compton camera based on cerium-doped Gd
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Lingqin, Kong, Lei, Shuai, Xiuzuo, Liang, Daowu, Li, Jipeng, Zhang, Wei, Zhou, Yao, Yang, Xiaoming, Wang, Xuanhou, Hu, Chunmiao, Li, Yue, Yu, Yi, Ding, Fanhui, Meng, Yiwen, Zhang, and Long, Wei
- Abstract
In this study, we propose a hybrid coded-aperture and Compton camera based on cerium-doped Gd
- Published
- 2022
7. Comparison of the modified uniformly redundant array with the Singer array for near-field coded aperture imaging of multiple sources
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Xin Li, Zhiming Zhang, Daowu Li, Yingjie Wang, Xiuzuo Liang, Wei Zhou, Mian Wang, Xiaoming Wang, Xuanhou Hu, Lei Shuai, and Yantao Liu
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Nuclear and High Energy Physics ,Instrumentation - Published
- 2023
8. Simulation research on time resolution based on Cherenkov radiation
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Wen He, Xianchao Huang, Long Wei, Zhiming Zhang, Wang Yingjie, Haohui Tang, Daowu Li, and Xiaorou Han
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Physics ,Nuclear and High Energy Physics ,Photon ,Physics::Instrumentation and Detectors ,business.industry ,Detector ,Photodetector ,Electron ,Charged particle ,Optics ,Nuclear Energy and Engineering ,Radiator (engine cooling) ,Quantum efficiency ,business ,Cherenkov radiation - Abstract
A faster time performance can be achieved by focusing on prompt emitted photons, such as Cherenkov photons. In this study, the time fluctuations of Cherenkov photons transmission in the three Cherenkov radiators were first simulated, and we evaluated the detector performance and discussed ways to improve the coincidence time resolution (CTR) results for the detector with the three radiators. Finally, we compared detection efficiency of Cherenkov radiation in three radiators. In this work, we recorded the step-by-step information of Cherenkov photons and the electrons that produced them in the radiator, information of photons on the photon outputting surface, and the step-by-step information tracing of the parent charged particles (electrons) to evaluate the factors influencing the performance time of the detector based on Geant4. Specially, we usually use a photon amplitude timing in the experimental implements, and the arrival time of an event is defined as the arrival time of the first photon of the event accordingly. The time fluctuations of Cherenkov photons transmission in the three Cherenkov radiators with a 5 mm length were simulated as 28.5 ps for PbF, 40.1 ps for PbWO4, and 24.7 ps for Al2O3. After considering other factors such as quantum efficiency (QE) of 30% and transit time spread (TTS) of 10 ps from the process of practical electronics, the CTR of a pair of single-pixel detectors were 56.6 ps for PbF2, 78.8 ps for PbWO4, and 46.3 ps for Al2O3 with a thickness of 5 mm. The detection efficiency of PbF2 is 32.25%, PbWO4 of 31.91% and Al2O3 of 8.14% in the case of 5 mm length. The simulation results indicated that using the Cherenkov photons produced in PbF2, PbWO4, Al2O3 for detector timing can obtain good CTR results. In this study, it demonstrates that it is possible to achieve a pretty good CTR with an improved QE and a reduced TTS of the photodetector.
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- 2021
9. DESIGN, CONSTRUCTION AND TEST OF GAMMA IONIZATION CHAMBERS
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Weihua Zhang, Yi Zhang, Mingyan Sun, Meiling Zhu, Xianchao Huang, Teng Tong, and Daowu Li
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Radiation ,Radiological and Ultrasound Technology ,Health Status ,Public Health, Environmental and Occupational Health ,Radiology, Nuclear Medicine and imaging ,General Medicine - Abstract
Ionization chamber is considered as the golden standard for the dosemeter. This work fabricated one graphite-walled and two polymethyl methacrylate (PMMA)-walled ionization chambers, tested respectively and compared their characteristic parameters. The performance of graphite-walled chamber was similar to that of the PMMA-walled chamber. The relative energy response of ionization chambers was lower than 4% from 50 keV to 50 MeV based on the FLUKA code simulation results. The experimental data showed that the ionization chambers performed well in linearity and repeatability. Assuming the chambers sensitive volume and HV bias was constant, the measured maximum saturation absorbed dose of ionization chambers changed with the diameter variation of chambers anode based on the comparison results of two PMMA-walled ionization chambers.
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- 2022
10. Compact MPPC-based coded aperture imaging camera for dual-particle detection
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Xuanhou Hu, Daowu Li, Yu Yue, Xiaoyu Pang, Yiwen Zhang, Xiaoming Wang, Liu Shuangquan, Shuai Lei, Xiuzuo Liang, Long Wei, Jiale Cai, and Jing Guo
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Physics ,Nuclear and High Energy Physics ,Physics::Instrumentation and Detectors ,business.industry ,Astrophysics::High Energy Astrophysical Phenomena ,Gamma ray ,Neutron radiation ,Scintillator ,Neutron temperature ,Optics ,Nuclear Energy and Engineering ,Figure of merit ,Neutron source ,Neutron ,Coded aperture ,business - Abstract
Fast neutrons and gamma-ray imaging detection is an effective way to detect and identify radioactive material in the field of nuclear security. A compact coded aperture imaging (CAI) camera was designed to be sensitive to both gamma and neutron radiation based on plastic scintillators and multi-pixel photon counters (MPPC). MPPCs coupling with the 13 × 13 pixelated plastic scintillators one-to-one were utilized to reduce the scale of the CAI system while maintaining good positional performance. The symmetric charge division (SCD) circuit was adopted to reduce the 169 signals output from the MPPC array to 26. Each waveform was collected and processed with four Domino Ring Sampler 4 (DRS4) chips and two 16-channel analog-to-digital converter (ADC) modules. As the pulse shapes of fast neutrons would be broadened after elastic scattering multiple times in the scintillators, the Anger-Logic method was applied to eliminate multiple elastic scattering events so that good pulse shape discrimination (PSD) performance can be achieved. The imaging and detection ability of the camera was evaluated using the 241Am-Be (5.9 × 105 n/s) neutron source and 137Cs (370 MBq) gamma source. The camera can be used to detect fast neutrons (0.5–10 MeV) and gamma rays (0.2–2.5 MeV). Furthermore, it can implement efficient neutron/gamma PSD capabilities in the mixed-field environment. The figure of merit (FOM) of the camera calculated at 400keVee energy cut is 0.93. A compact MPPC-based CAI camera was designed to detect and discriminate fast neutrons and gamma rays. Its good PSD performance was well suited to distinguish fast neutrons from gamma rays in a dual-particle environment. The portable design makes it promising for complex monitoring scenarios in nuclear security.
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- 2021
11. A real-time peak-detection approach for nuclear detection and its implementation on an FPGA
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Long Wei, Yan Li, Hu Tingting, Yang Yao, Daowu Li, and Zhang Jipeng
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Data stream ,Nuclear and High Energy Physics ,Nuclear Energy and Engineering ,Nuclear detection ,Stochastic process ,Computer science ,Histogram ,Waveform ,Error detection and correction ,Algorithm ,Signal ,Energy (signal processing) - Abstract
Detecting a pulse correctly is a key process in nuclear detection. Because the radiation emission is a random process, it is hard to design a suitable peak-detection approach in FPGA. The error detection will influence the final energy spectrum and flood histogram. In order to improve the result of nuclear detection, this paper proposes a novel method for nuclear signal peak-detection, which can improve both the effective counting rate and the quality of pulses in real-time. The main method is to establish a normalized reference pulse regardless of waveform through the least squares method. By calculating the loss between the incoming data stream and normalized reference pulse, this algorithm retains the pulses whose loss is below the threshold. We select the threshold based on statistical methods. The algorithm is implemented on field programmable gate array (FPGA) successfully, and this process is able to work in real-time. The result shows that the effective counting rate can improve about 19.8% and more than 99% pile-up and error pulses will be suppressed. By analyzing reserved pulses, the energy spectrum and flood histogram could be well rectified. The energy resolution increases 11% compared with traditional algorithm. Furthermore, due to this new algorithm, the low-energy threshold can be lower.
- Published
- 2020
12. Achieving sub-pixel position resolution and sub-millimeter depth resolution using a pixelated CdZnTe detector
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Chao Wang, Long Wei, Zhiming Zhang, Daowu Li, Baotong Feng, Yantao Liu, Yu Xiang, Xin Li, and Xiaopan Jiang
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Nuclear and High Energy Physics ,Instrumentation - Published
- 2022
13. A Classifier for Nuclear Pulse Detection based on CNN
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Yang Yao, Wei Long, and Daowu Li
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Nuclear detection ,Computer science ,Feature (computer vision) ,Orientation (computer vision) ,business.industry ,Histogram ,Classifier (linguistics) ,Pattern recognition ,Artificial intelligence ,Focus (optics) ,business ,Convolutional neural network ,Convolution - Abstract
In the field of nuclear detection, there is a basic task to identify the category and orientation of radioactive source. The category and orientation depend on the energy spectrum and flood histogram which is the statistic of qualified pulses. In this paper, we propose a novel method to distinguish qualified pulses and disqualified pulses with a classification based on convolution neural network (CNN). Although many other methods also focus on this task, they have many defects, for instance they can only get energy spectrum, or they cannot get counting rate accurately. By analyzing the problem, we can find that convolution neural network is a good method to solve this problem. The advantages of our methods are: 1) Our model can reach high accuracy even though the training dataset is not very large. 2) Because convolution layer can ensure the consistency of displacement and scale, it is a good idea to extract the feature of pulses with 1D convolution kernel. 3) This model is small, the precision can reach more than 95% and the recall can reach 98% in few iterations. The result is good enough to recall final results. After the qualified pulses are reserved, we can get the energy spectrum and flood histogram at the same time. We use two different radioactive sources to test the method. The results show that both the energy spectrum and flood histogram are revised no matter in low radiation intensity nor in high radiation intensity. The inference is realized on computer to generate correct energy spectrum and flood histogram which would help to track the orientation of category of radioactive source.
- Published
- 2020
14. A compact, high signal-to-noise ratio line-detector array Compton scatter imaging system based on silicon photomultipliers
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Xiong, Xiao, primary, Yantao, Liu, additional, Daquan, Cao, additional, Wei, Zhou, additional, Xiaoming, Wang, additional, Yingjie, Wang, additional, Daowu, Li, additional, Haohui, Tang, additional, Xianchao, Huang, additional, Xiaopan, Jiang, additional, Yiwen, Zhang, additional, Zhenrui, Lu, additional, Jipeng, Zhang, additional, Xiuzuo, Liang, additional, Xiaoyu, Pang, additional, Chao, Wang, additional, Long, Wei, additional, and Zhiming, Zhang, additional
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- 2019
- Full Text
- View/download PDF
15. Development and evaluation of a double-plane detector system for multi-radionuclide imaging
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Lu Zhenrui, Wang Yingjie, ChuangXin Ma, Xianchao Huang, Long Wei, Xiao-Li Sun, Lin Li, Daquan Cao, Chai Pei, Zhiming Zhang, Daowu Li, Haohui Tang, Gu Xiaoyue, and Wei Zhou
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Nuclear and High Energy Physics ,Materials science ,medicine.diagnostic_test ,Pixel ,Breast imaging ,business.industry ,Detector ,Lyso ,Optics ,Silicon photomultiplier ,Data acquisition ,Nuclear Energy and Engineering ,Positron emission tomography ,medicine ,business ,Image resolution - Abstract
To develop a multi-radionuclide imaging system with a flexible and compact structure that has a potential for breast and other applications, and to evaluate its performances under both positron emission tomography and single photon emission imaging conditions. The plane detector was composed of 5 × 6 blocks with an effective detection area of 168.6 mm × 202.4 mm. Each block consisted of a 16 × 16 LYSO array. The pixel size is 1.9 mm × 1.9 mm × 15 mm. An 8 × 8 silicon photomultiplier (SiPM) array with SensL’s C-30035 sensors was coupled to the LYSO array, separated by a 1.5-mm-thick glass. To minimize the influence of temperature on the detector, the active part of the front-end electronics was kept away from SiPMs. Self-designed data acquisition system and reconstruction software were utilized to evaluate the performances of the whole system. All the blocks had excellent pixels identification. An average energy resolution of 11.39% for 511 keV and 21.37% for 140 keV was obtained. In the PET mode, the best spatial resolution was better than 2 mm and the system sensitivity reached up to 11.05% at 60 mm distance. In the single photon emission imaging mode, a spatial resolution better than 3 mm was obtained. The results indicated that the system has a good overall performance and can be used in breast imaging and other general PET applications. It also has the potential to be used for single photon emission imaging. In pursuit of a better spatial resolution of cross-plane, PSF and DOI technology will be developed in the next work. For specific applications, further improvement of the detector system such as performance evaluation with phantoms will be carried out.
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- 2019
16. Fast pulse sampling module for real-time neutron–gamma discrimination
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Jiale Cai, Zhiming Zhang, Wei Zhou, Li Xiaohui, Long Wei, P. L. Wang, Baotong Feng, Daowu Li, Tong Teng, and Hu Tingting
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Nuclear and High Energy Physics ,Photomultiplier ,010308 nuclear & particles physics ,Computer science ,Detector ,Sampling (statistics) ,Dead time ,Chip ,01 natural sciences ,Particle detector ,Nuclear Energy and Engineering ,0103 physical sciences ,Electronic engineering ,Neutron detection ,Waveform ,010306 general physics - Abstract
An adaptable and compact fast pulse sampling module was developed for the neutron–gamma discrimination. The developed module is well suited for low-cost and low-power consumption applications. It is based on the Domino Ring Sampler 4 (DRS4) chip, which offers fast sampling speeds up to 5.12 giga samples per second (GSPS) to digitize pulses from front-end detectors. The high-resolution GSPS data is useful for obtaining precise real-time neutron–gamma discrimination results directly in this module. In this study, we have implemented real-time data analysis in a field programmable gate array. Real-time data analysis involves two aspects: digital waveform integral and digital pulse shape discrimination (PSD). It can significantly reduce the system dead time and data rate processed offline. Plastic scintillators (EJ-299-33), which have proven capable of PSD, were adopted as neutron detectors in the experiments. A photomultiplier tube (PMT) (model #XP2020) was coupled to one end of a detector to collect the output light from it. The pulse output from the anode of the PMT was directly passed onto the fast sampling module. The fast pulse sampling module was operated at 1 GSPS and 2 GSPS in these experiments, and the AmBe-241 source was used to examine the neutron–gamma discrimination quality. The PSD results with different sampling rates and energy thresholds were evaluated. The figure of merit (FOM) was used to describe the neutron–gamma discrimination quality. The best FOM value of 0.91 was obtained at 2 GSPS and 1 GSPS sampling rates with an energy threshold of 1.5 MeVee (electron equivalent).
- Published
- 2019
17. Design of a high-sampling-rate electronic module for array-detector positron annihilation lifetime measurements
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Fuyan Liu, Jiale Cai, Xingzhong Cao, Long Wei, P. L. Wang, Wang Yingjie, Baoyi Wang, Zhiming Zhang, Haohui Tang, and Daowu Li
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Physics ,Nuclear and High Energy Physics ,Flash (photography) ,Data acquisition ,Nuclear Energy and Engineering ,System of measurement ,Detector ,Electronic engineering ,Constant fraction discriminator ,Field-programmable gate array ,Chip ,Communication channel - Abstract
In this study, a high-time-resolution electronic module with a high channel density and low power consumption was designed for the measurement of the multi-detector array positron annihilation lifetimes. This electronic module consisted of 32 input channels, and each channel provided a high sampling rate up to 5.12 GSPS based on a Domino Ring Sampler 4 (DRS4) chip. Compared to the high-speed flash analog-digital converter (FADC), DRS4 chip has a higher channel density with an affordable lower price and power consumption. The developed electronic module was also capable of real-time data analysis for directly extracting the time information of input signals at the data acquisition site, thereby significantly decreasing the data rate. The digital constant fraction discriminator (DCFD) algorithm was implemented in the field programmable gate array (FPGA) for performing the time pick-up. The coincidence time resolution of the electronic module was measured, and the test results revealed a value of 26 ps. A prototypical 16-pixel detector module of the multi-detector system was evaluated using this electronic module, and the coincidence time resolution of the prototypical module was 411.84 ps. The electronic module was confirmed to satisfy the severe requirements of the multi-array-detector positron annihilation lifetime measurement system. It was also suitable for other high-time-resolution, high-channel-density, cost-effective, and low-power-consumption applications.
- Published
- 2019
18. Prototype of an array SiPM-based scintillator Compton camera for radioactive materials detection
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Xiuzuo Liang, Yi Liu, Jiale Cai, Zhiming Zhang, Xianchao Huang, Xiaoyu Pang, Long Wei, Xiong Xiao, Daowu Li, Zhang Jipeng, and Shuai Lei
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Physics ,Nuclear and High Energy Physics ,Pixel ,Physics::Instrumentation and Detectors ,Point source ,business.industry ,Astrophysics::High Energy Astrophysical Phenomena ,Detector ,Compton scattering ,Scintillator ,Silicon photomultiplier ,Optics ,Data acquisition ,Nuclear Energy and Engineering ,Angular resolution ,business - Abstract
The Compton camera, which visualizes the distribution of gamma-ray sources based on the kinematics of Compton scattering, has advantage of wide field of view, broad range of energy and compact structure. In this study, we proposed a prototype of Compton camera, which included array silicon photomultiplier (SiPM)-based position-sensitive detectors, data acquisition (DAQ) system and image reconstruction system. The detectors were composed of Ce-doped Gd3Al2Ga3O12 scintillator arrays and pixel Si-PM arrays. In DAQ system, symmetric charge division circuit, impedance bridge circuit and the delay coincidence algorithm were designed to record coincidence events. Simple back-projection algorithm and list-mode maximum likelihood expectation maximization algorithm were adopted for image reconstruction. The coordinate of longitude and latitude was used for image fusion. The performance of this Compton camera prototype system was evaluated. The results indicated that this system was able to locate a 137Cs point source within 20 s with the corresponding radiation dose of ~ 1.0 μSv/h. The angular resolution of point source was ~ 7° (FWHM), and the total energy resolution of 662 keV was 7.2%. Furthermore, we succeeded in separating two point sources of different energy [22Na (511 keV), 137Cs (662 keV)] in laboratory test. This prototype of scintillator Compton camera offers capabilities for applications like source term investigation and radioactive materials detection.
- Published
- 2019
19. Development of a portable Single Sphere Neutron Spectrometer
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Hongbin Kang, Baotong Feng, Wang Yingjie, Mengze Tao, Daowu Li, Zhu Meiling, and Weihua Zhang
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Physics ,Radiation ,Spectrometer ,Physics::Instrumentation and Detectors ,business.industry ,Nuclear Theory ,Detector ,Scintillator ,Neutron temperature ,Metrology ,Silicon photomultiplier ,Optics ,Neutron source ,Neutron ,Nuclear Experiment ,business ,Instrumentation - Abstract
A portable Single Sphere Neutron Spectrometer (SSNS) is designed to measure the neutron energy spectrum in the mixed radiation field. The spectrometer consists of a 30 cm diameter single polyethylene moderating sphere with 19 pieces 6Li and 1-piece 7Li glass scintillator detectors located at the orthogonal X/Y/Z axis. The output signals from each detector are processed and readout by the Silicon Photomultipliers (SiPMs) and the Application Specific Integrated Circuit (ASIC) electronic system. The neutron energy responses of portable SSNS are calibrated in the mono-energetic neutron reference fields (144 keV, 1.2 MeV, 5 MeV, 14.8 MeV) based on the 5SDH-2 tandem accelerator in China Institute of Atomic Energy, which are also simulated from 0.0253 eV to 20 MeV by Monte Carlo simulation. The performance of portable SSNS is tested at different distances in 241Am–Be neutron reference radiation field in National Institute of Metrology, China. The fluence response of SSNS is about 0.28 cm2 for 241Am–Be neutron source.
- Published
- 2021
20. High-performance coded aperture gamma camera based on monolithic GAGG:Ce crystal
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Wei Zhou, Wang Yingjie, Jiajia Zhai, Baotong Feng, Wen He, Haohui Tang, Zhiming Zhang, Daowu Li, Xiangtao Zeng, Xiaorou Han, Zhu Meiling, Xiuzuo Liang, Xianchao Huang, and Long Wei
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010302 applied physics ,Materials science ,business.industry ,Detector ,Resolution (electron density) ,chemistry.chemical_element ,01 natural sciences ,010305 fluids & plasmas ,law.invention ,Crystal ,Optics ,Silicon photomultiplier ,chemistry ,law ,0103 physical sciences ,Calibration ,Coded aperture ,Gallium ,business ,Instrumentation ,Gamma camera - Abstract
A 50 × 50 × 10 mm3 monolithic gadolinium aluminum gallium garnet (Gd3Al2Ga3O12; GAGG):Ce crystal coupled to a 8 × 8 silicon photomultiplier (SiPM) array was developed; it showed very good system uniformity and a high energy resolution of 7.4% at 662 keV. By using a convolutional neural network-based positioning algorithm and a fan-beam calibration method, the detector achieved a position resolution of ∼1.4 mm and a depth of interaction resolution of ∼2 mm. Based on this high-performance monolithic detector, we developed a coded aperture gamma camera. A 1-mCi Cs-137 source centered at a 2-m distance from the mask could be reconstructed with a signal-to-noise ratio of 6.5 in 1 s. Furthermore, the imaging ability of a low-energy Am-241 source and a low-activity Cs-137 source when the background-to-signal ratio was approximately 1:1 and a double low-activity source (Cs-137 and Na-22) was demonstrated. It is shown that the monolithic-crystal-based coded aperture gamma camera can achieve high performance and has a large potential for further improvement.
- Published
- 2021
21. Performance Evaluation and Initial Clinical Test of the Positron Emission Mammography System (PEMi)
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P. L. Wang, Baotong Feng, Peng-Fei Yin, Yun Mingkai, Xianchao Huang, Zhiming Zhang, Dong Dai, Daowu Li, Long Wei, Lin Li, Chai Pei, Gu Xiaoyue, and Wen-Gui Xu
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Nuclear and High Energy Physics ,Photomultiplier ,medicine.medical_specialty ,Materials science ,business.industry ,Resolution (electron density) ,Imaging phantom ,Full width at half maximum ,Optics ,Nuclear Energy and Engineering ,Medical imaging ,medicine ,Positron emission mammography ,Medical physics ,Sensitivity (control systems) ,Electrical and Electronic Engineering ,business ,Image resolution - Abstract
A new polygon positron emission mammography imaging system (PEMi) was developed in 2009 by the Institute of High Energy Physics, Chinese Academy of Sciences. PEMi is constructed in a polygon structure with lutetium yttrium orthosilicate crystal arrays mounted on a position-sensitive photomultiplier. The system consists of 64 blocks and each block is arranged in $16 \times 16$ crystal arrays with a pixel size of $1.9~\times 1.9~ \times 15$ mm. The diameter of the detector ring is 166 mm, and the axial length is 128 mm. The transaxial field of view of PEMi is 110 mm. The goal of the initial study was to test PEMi’s performance and the clinical imaging ability with a small group of selected subjects. The detectors have a measured intrinsic spatial resolution averaging 1.67 mm. The axial and tangential resolution remained under 2.5-mm full width at half maximum within the central 5-cm diameter of the field of view. The hot rods with a diameter of 1.7 mm can be clearly identified, and the structure of the region containing 1.35-mm diameter rods can also be observed. Using a 6-ns coincidence timing window and a ${\hbox {360}} \sim {\hbox {660}}$ -keV energy window, the peak sensitivity of the tomograph is 6.88%. The noise-equivalent count rate peak is 110 $\thinspace$ 766 cps for a breast-like cylindrical phantom of 100 mm in diameter at an activity concentration of $0.03~\hbox{MBq}/{\rm cc}$ . The recovery coefficients ranged from 0.21 to 0.85 for rods between 1 mm and 5 mm in the image-quality phantom. The reconstructed image resolution achieved an improvement compared with whole-body positron emission tomography (PET), which might reduce the lower threshold on detectable lesion size. Example patient images demonstrate that PEMi is clinically feasible. And more detailed structure information was obtained with PEMi than with the whole-body PET imaging.
- Published
- 2015
22. Self-supporting design of a time-encoded aperture, gamma-neutron imaging system
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Daquan Cao, Shuai Lei, Zhibo Zhou, Jilong Zhang, Xiaoyu Pang, Xiaoming Wang, Xiaorou Han, Long Wei, Qi liu, Hu Tingting, Xuanhou Hu, Zhang Jipeng, Zhiming Zhang, Likun Liu, Yiwen Zhang, Daowu Li, Liu Shuangquan, Xiuzuo Liang, and Fanhui Meng
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Physics ,Nuclear and High Energy Physics ,010308 nuclear & particles physics ,business.industry ,Aperture ,Point source ,Neutron imaging ,Radiation ,01 natural sciences ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Optics ,0103 physical sciences ,Systems design ,Neutron ,Sensitivity (control systems) ,business ,Instrumentation ,Decoding methods - Abstract
A self-supporting, 2-D, time-encoded aperture system was developed for both gamma and neutron imaging. The system achieved high sensitivity for imaging due to the use of an M–P array which has flat sidelobes of cross-correlation reconstruction and is self-supporting. It is demonstrated that a 24.4 μ Ci 137 Cs radiological point source could be detected within 10 min when the source-to-background ratio is 1:1. Several radiation scenes support that the system has an imaging capability of multipoint, extended, and gamma/neutron discrimination sources. The features of good cross-correlation decoding properties, panoramic imaging, and rapid reconstruction make such a system design attractive and prospective for the localization of radioactive hot spots.
- Published
- 2020
23. Real-time soft error testing system for large-area QDR II+ SRAM array on the Tibetan Plateau
- Author
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Li Xiaohui, P. L. Wang, Baotong Feng, Hu Tingting, Lei Zhifeng, Teng Tong, Zhang Zhangang, Cunfeng Wei, Mohan Li, and Daowu Li
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010302 applied physics ,Physics ,business.industry ,020208 electrical & electronic engineering ,02 engineering and technology ,Condensed Matter Physics ,Plateau (mathematics) ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Soft error ,CMOS ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Signal integrity ,Static random-access memory ,Electrical and Electronic Engineering ,Safety, Risk, Reliability and Quality ,business ,Field-programmable gate array ,Computer hardware - Abstract
In this study, a real-time testing system consisting of a large-area array of 72 QDR II+ SRAMs (larger than 10-Gbit manufactured in 65 nm CMOS technology) was developed and assembled on the Tibetan Plateau at an altitude of 4300 m. A new topological structure with 9 QDR II+ devices operating synchronously by a single FPGA was proposed and the signal integrity of the large-area high-speed QDR II+ SRAMs was solved. Under harsh natural radiation conditions, the complex and expensive system monitored a large number of devices in parallel for 153 days uninterruptedly. 43 soft errors including single bit upsets (SBUs), multiple-cell upsets (MCUs), single event induced hard errors (SHEs) and burst errors were observed, with a calculated SER value of 2356 FIT/Mb. Meanwhile, these results effectively validated the testing system.
- Published
- 2019
24. A compact MPPC-based camera for omnidirectional (4π) fast-neutron imaging based on double neutron–proton elastic scattering
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Xiong Xiao, Xiaoyu Pang, Daquan Cao, Zhiming Zhang, Wang Yingjie, Xiuzuo Liang, Wei Zhou, Zhang Jipeng, Xiaopan Jiang, Liu Yantao, Shuai Lei, Daowu Li, Yiwen Zhang, and Long Wei
- Subjects
010302 applied physics ,Elastic scattering ,Physics ,Nuclear and High Energy Physics ,010308 nuclear & particles physics ,business.industry ,Astrophysics::High Energy Astrophysical Phenomena ,Neutron imaging ,Nuclear Theory ,Neutron scattering ,Scintillator ,01 natural sciences ,Neutron temperature ,Optics ,Omnidirectional camera ,0103 physical sciences ,Neutron source ,Neutron ,Nuclear Experiment ,business ,Instrumentation - Abstract
Neutron localization, which finds (localizes) neutron sources , is a non-destructive method used in the application of nuclear emergency response and special nuclear material (SNM) localization. Fast neutrons from SNM fission can be detected using a hydrogen-rich scintillation detector system with relatively high efficiency. In this study, we proposed a compact multi-pixel photon counter (MPPC)-based neutron scattering camera prototype consisting of sixteen plastic scintillator pillars. This camera is capable of detecting fast neutrons produced by neutron sources in the far-field. It provides a three-dimensional structure to detect incident neutrons with omnidirectional (4 π ) field-of-view. Based on double neutron–proton elastic scattering, a reconstructed image can be achieved by using an Am–Be source. Besides, time-of-flight technology was adopted for separating neutron signals from the gamma-ray background radiation. The results of the imaging efficiency and the average imaging resolution are reported in this article. This camera offers good prospects to expand the application field of SNM localization for nuclear security and proliferation deterrence.
- Published
- 2019
25. Design of readout electronics based on peak-holding circuit and multiplexer for a fast neutron spectrometer
- Author
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P. L. Wang, Baotong Feng, Xue Yuxiong, Li Xiaohui, Wei Zhou, Zhuang Kai, Junguang Zhou, Qin Xiubo, Teng Tong, Zhiming Zhang, Jiale Cai, Liyang Sun, An Heng, Xuanhou Hu, Huang Huan, Wang Yingjie, Fanhui Meng, Xiaoming Wang, Zeng Fanjian, and Daowu Li
- Subjects
Physics ,Nuclear and High Energy Physics ,Spectrometer ,Physics::Instrumentation and Detectors ,business.industry ,Detector ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Multiplexer ,Nuclear Energy and Engineering ,0103 physical sciences ,Optoelectronics ,Neutron detection ,Neutron ,Electronics ,010306 general physics ,0210 nano-technology ,business ,Energy (signal processing) ,Electronic circuit - Abstract
Fast neutron detection is meaningful in many research fields such as space environment monitoring. A scintillating fiber array model for fast neutron detection was proposed and developed in 1980s. Aerospace applications of the model require electronics in small size. To design a dedicated electronic system to readout and process the 384-channel signals from scintillating fiber array, and to use the designed system to fabricate a neutron detector for aerospace applications. With the method of nuclear recoil, fast neutron is detected by tracking recoil proton of n–p scatter in scintillating plastic fibers. Using the peak-holding circuits and multiplexers, the system size and power consumption were reduced. The detector fabricated with the designed system, had 34 cm $$\times $$ 34 cm $$\times $$ 27 cm mechanical size, 20.4 kg weight, and 30.05 W power consumption. Comparing to traditional waveform sampling electronics, the designed electronics was highly integrated and had a small size. The readout electronics also gave a better energy resolution of 39% in neutron detection, while the energy resolution was 43% in previous version. In this study, a highly integrated readout electronic system was designed and verified. The detector using the system gave good performance. The designed electronics had potential development in fast neutron detection and other high energy physics detection system.
- Published
- 2018
26. Development of a fast neutron spectrometer based on a plastic fiber array
- Author
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An Heng, P. L. Wang, Baotong Feng, Zeng Fanjian, Daowu Li, Qin Xiubo, Zhiming Zhang, Xue Yuxiong, Li Detian, Jiale Cai, Xiaoming Wang, Liyang Sun, and Zhuang Kai
- Subjects
Bonner sphere ,Nuclear and High Energy Physics ,Scintillation ,Photomultiplier ,Optical fiber ,Materials science ,Spectrometer ,Physics::Instrumentation and Detectors ,Dynamic range ,business.industry ,Detector ,Analytical chemistry ,Physics::Optics ,01 natural sciences ,law.invention ,Optics ,Nuclear Energy and Engineering ,law ,0103 physical sciences ,Neutron ,business ,010303 astronomy & astrophysics - Abstract
A three-dimensional position-sensitive fast neutron spectrometer is designed to measure fast neutron spectrum over 10 MeV. The detector consists of a 16 $$\times $$ 16 mutually perpendicular plastic scintillation fiber array coupled to $$2 \times 2$$ Hamamatsu H8500C position-sensitive photomultiplier tubes by optical fibers. The fiber array is fabricated with 0.5 mm $$\times $$ 3 mm fibers and 3-mm square fibers. Due to the combined application of different sizes of fibers, the detector can broaden energy dynamic range and meanwhile have good detection efficiency. The method of the combined application of different sizes of plastic fibers in the array may provide a solution to measure wider energy range of solar neutrons. In this paper, we used FLUKA to simulate the performance of the detector model and report the results of experimental studies with neutrons from a pulsed D-T neutron.
- Published
- 2017
27. A QTC-based signal readout for position-sensitive multi-output detectors
- Author
-
Xianchao Huang, Li Xiaohui, Zhiming Zhang, Yan Chen, Long Wei, Wei Zhou, Xiong Xiao, Yiwen Zhang, Sun Shifeng, Liu Yantao, Daowu Li, P. L. Wang, Baotong Feng, Gu Xiaoyue, Hu Tingting, Yang Mingjie, and Wang Yingjie
- Subjects
Physics ,Nuclear and High Energy Physics ,Photomultiplier ,Physics::Instrumentation and Detectors ,010308 nuclear & particles physics ,business.industry ,Detector ,01 natural sciences ,Signal ,030218 nuclear medicine & medical imaging ,Time-to-digital converter ,03 medical and health sciences ,0302 clinical medicine ,Optics ,Nuclear Energy and Engineering ,Application-specific integrated circuit ,visual_art ,0103 physical sciences ,Electronic component ,visual_art.visual_art_medium ,Electronics ,business ,Field-programmable gate array ,Simulation - Abstract
A new signal readout method for position-sensitive multi-output detectors, such as those in high-energy spectroscopy measurement and nuclear imaging, was developed by combining the charge division circuit, summing circuit and charge-to-time conversion (QTC) circuit. The 64 outputs of a Hamamatsu H8500 position-sensitive photomultiplier tube were processed, and three digital pulses were generated. The widths of digital pulses were determined using the time-to-digital converter in an field programmable gate array. The energy and position information of incident γ-rays is estimated based on the proportionality between the width of digital pulses and input charge created by γ-photons. A prototype was built using discrete components and tested, and the energy and position resolutions were improved compared with that obtained with standard ADCs. This method greatly simplifies the front-end electronics and the digital interface. It enables a compact electronics system and an easy integration into an ASIC.
- Published
- 2016
28. Fast and accurate generation method of PSF-based system matrix for PET reconstruction
- Author
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Haohui Tang, Gao Juan, Long Wei, Zhiming Zhang, Liu Shuangquan, Chai Pei, Daowu Li, Xiao-Li Sun, Li Mohan, and Yun Mingkai
- Subjects
Physics ,Point spread function ,Nuclear and High Energy Physics ,Photon ,medicine.diagnostic_test ,010308 nuclear & particles physics ,Monte Carlo method ,FOS: Physical sciences ,Astronomy and Astrophysics ,Image processing ,Iterative reconstruction ,01 natural sciences ,Homogenization (chemistry) ,Physics - Medical Physics ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,0103 physical sciences ,medicine ,Tomography ,Medical Physics (physics.med-ph) ,Instrumentation ,Algorithm ,Emission computed tomography - Abstract
Positional single photon incidence response (P-SPIR) theory is researched in this paper to generate more accurate PSF-contained system matrix simply and quickly. The method has been proved highly effective to improve the spatial resolution by applying to the Eplus-260 primate PET designed by the Institute of High Energy Physics of the Chinese Academy of Sciences(IHEP). Simultaneously, to meet the clinical needs, GPU acceleration is put to use. Basically, P-SPIR theory takes both incidence angle and incidence position by crystal subdivision instead of only incidence angle into consideration based on Geant4 Application for Emission Tomography (GATE). The simulation conforms to the actual response distribution and can be completed rapidly within less than 1s. Furthermore,two-block penetration and normalization of the response probability are raised to fit the reality. With PSF obtained, the homogenization model is analyzed to calculate the spread distribution of bins within a few minutes for system matrix generation. As a reult, The images reconstructed indicate that the P-SPIR method can effectively inhibit the depth of interaction (DOI) effect especially in the field close to the edge of the field of view (FOV). What is more, the method can be promoted to any other PET and the list-mode organization structure high-speedily and efficiently, which substantially reduces the computing cost and ensures the accuracy of system matrix for PET reconstruction., Comment: 6 pages,12 figures
- Published
- 2016
- Full Text
- View/download PDF
29. Design and performance evaluation of a compact, large-area PET detector module based on silicon photomultipliers
- Author
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Long Wei, Wang Yingjie, Shuai Lei, Feng Baotong, Zhiming Zhang, Xianchao Huang, Li Ting, Daowu Li, Haohui Tang, Liu Shuangquan, Chai Pei, Liu Yantao, Baoyi Wang, Yiwen Zhang, Yan Chen, and Yan-Fei Liao
- Subjects
Physics ,Nuclear and High Energy Physics ,Photomultiplier ,medicine.medical_specialty ,Silicon ,business.industry ,Antenna aperture ,Detector ,Resolution (electron density) ,chemistry.chemical_element ,Lyso ,Silicon photomultiplier ,Optics ,chemistry ,medicine ,Medical physics ,business ,Instrumentation ,Image resolution - Abstract
A PET module that comprises a pair of compact, high-resolution and large-area detectors based on silicon photomultipliers (SiPM) was developed and evaluated. The detector's effective area was 24 mm x 24 mm. LYSO crystals measuring 1.9 mm x 1.9 mm x 10 mm and charge division circuit were employed to obtain high spatial resolution with relatively concise Front-end electronics (FEE). Initial results showed the detector to be compatible with 1.5 T magnetic fields. The system's intrinsic FWHM spatial resolution is 1.50 mm. The average energy resolution is 18.5% and the coincidence timing resolution is 2.6 ns. (C) 2011 Elsevier B.V. All rights reserved.
- Published
- 2012
30. Development of a portable gamma imager based on SiPM and coded aperture technology
- Author
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Wang Yingjie, Shuai Lei, Cunfeng Wei, Long Wei, Zhiming Zhang, Daowu Li, and Hu Tingting
- Subjects
Physics ,Digital electronics ,business.industry ,Instrumentation ,Detector ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Video camera ,Scintillator ,law.invention ,Silicon photomultiplier ,Optics ,law ,Coded aperture ,Field-programmable gate array ,business - Abstract
This paper describes the instrumentation of an integrated remote radiation imager used in environmental measurement. The system consists of gamma ray detector, coded aperture mask, video camera, FPGA based digital electronics, embedded control system and screen. The detector is based on a 5×5 SiPM array coupled with 11×11 YSO scintillator array with the pitch size of 1.8mm. The modified uniformly redundant array coded aperture mask was used to enable the system with greater sensitivity. The device can take images of the radiation distribution of the vision field, which is fused with optical image and then displayed on LED screen. Preliminary experiment results showed that the imaging system was full functional. The imager weighs only 2.8kg and is powered by lithium battery, being the most portable one among similar-type instruments reported up to now.
- Published
- 2015
31. Performance evaluation of a parallel-hole collimated detector module for animal SPECT imaging
- Author
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Long Wei, Yan-Fei Liao, P. L. Wang, Zhiming Zhang, Daowu Li, Li Ting, Junhui Liu, Baoci Shan, Haohui Tang, Xianchao Huang, Yan Chen, Wang Yingjie, and Baoyi Wang
- Subjects
Physics ,Nuclear and High Energy Physics ,Scintillation ,business.industry ,Detector ,Astronomy and Astrophysics ,Collimator ,Reconstruction algorithm ,Imaging phantom ,Collimated light ,law.invention ,Optics ,law ,Spect imaging ,business ,Instrumentation ,Image resolution - Abstract
We have built and investigated a detector module for animal SPECT imaging, especially for use in large field of view (FOV) conditions. The module consists of a PMT-based detector and a parallel-hole collimator with an effective area of 80 mm×80 mm. The detector is composed of a NaI scintillation crystal array coupled to four H8500 position sensitive photomultiplier tubes (PS-PMT). The intrinsic energy resolution of the detector is 11.5% at 140 keV on average. The planar spatial resolution of the module changes from 2.2 mm to 5.1 mm at different source-to-collimator distances with an unchanged sensitivity of about 34cps/MBq. Additionally, the SPECT Micro Deluxe Phantom imaging was performed with a radius of rotation (ROR) of 40 mm. Using the FBP reconstruction algorithm, a high performance image was obtained, indicating the feasibility of this detector module.
- Published
- 2011
32. Preliminary study of depth of interaction measurement for a PET detector
- Author
-
Xianchao Huang, Liu Shuangquan, P. L. Wang, Shujun Wei, Long Wei, Wang Yingjie, Daowu Li, Shuai Lei, Zhiming Zhang, Yan Chen, Yan-Fei Liao, Baoci Shan, and Junhui Liu
- Subjects
Physics ,Nuclear and High Energy Physics ,Photomultiplier ,Depth of interaction ,business.industry ,Resolution (electron density) ,Astronomy and Astrophysics ,Scintillator ,Lyso ,Crystal ,Optics ,Histogram ,business ,Instrumentation ,Layer (electronics) - Abstract
In this work we studied the feasibility of detecting the depth of interaction (DOI) with two layers of crystal arrays of LYSO and BGO scintillators coupled to a position-sensitive photomultiplier tube (PS-PMT) R8900-C12. A front-end electronics was designed, with which we got different pulse shapes for different crystals to obtain depth information. With the double integration method, we got the DOI histogram of a divided integration ratio of two crystals as the standard to determine the layer-of-interaction. The DOI accuracy, measured by scanning a 22Na slit source along the side of the module, was 98% for the LYSO layer and 95% for the BGO layer. The energy resolution at 511keV was 13.1% for LYSO and 17.1% for BGO. We obtained good crystal separation in 2D position histograms of both layers. These results could be useful in the manufacture of PET scanners with high spatial resolutions.
- Published
- 2011
33. A scintillating plastic fiber array and multiplexer based 384-channel fast neutron spectrometer
- Author
-
Xiu Bo Qin, Liyang Sun, P. L. Wang, Baotong Feng, Xue Yuxiong, Zhuang Kai, An Heng, Jiale Cai, Long Wei, Yang Mingjie, Wang Yingjie, Wei Zhou, Zeng Fanjian, Xiaoming Wang, Daowu Li, Li Xiaohui, and Zhiming Zhang
- Subjects
Photomultiplier ,Materials science ,Spectrometer ,Physics::Instrumentation and Detectors ,010308 nuclear & particles physics ,business.industry ,Nuclear Theory ,Detector ,01 natural sciences ,Neutron temperature ,Optics ,Nuclear electronics ,0103 physical sciences ,Neutron detection ,Neutron ,Fiber ,Nuclear Experiment ,business ,010303 astronomy & astrophysics ,Instrumentation - Abstract
A fast neutron detection system based on a scintillating plastic fiber array and multiplexer was designed to measure the spectrum of fast neutrons ranged 10 MeV-100 MeV. With the method of nuclear recoil, the energy of incident neutron was determined by measuring the recoil proton track and deposited energy in scintillating plastic fibers. The detection system was composed of a scintillating plastic fiber array, 6 position sensitive photomultiplier tubes, and a high-density readout electronics based on the multiplexer. The scintillating plastic fiber array was made as a staggered structure with two kinds of fibers in different sizes (0.5 mm-square fiber and 3 mm-square fiber). The structure provided a wider detection energy range and better detection efficiency than arrays made with uniform plastic fibers. A dedicated digital electronics system was well designed to control the whole readout system to provide 384-channel signal processing. The detector had a 48 mm × 48 mm effective detection area and a mechanical size of 34 cm × 34 cm × 27 cm. In the simulation of the detector model performance, the system gave an energy resolution of 23%-35% for neutrons ranged 10 MeV-100 MeV. Experimental results showed that the detector had a good energy linearity and energy resolutions were, respectively, 35.82% at 14.817 MeV, 36.84% at 21.264 MeV, 35.90% at 23.069 MeV, and 32.90% at 24.220 MeV. The optimized prototype model had potential in increasing fast neutron detection performance.
- Published
- 2017
34. Developing VUV spectroscopy for protein folding and material luminescence on beamline 4B8 at the Beijing Synchrotron Radiation Facility
- Author
-
Hao Zhuang, Daowu Li, Yan Huang, Shuaishuai Sun, Yinglei Tan, Ai-Yu Zhou, Ye Tao, and Zhenghua Gao
- Subjects
Protein Folding ,Nuclear and High Energy Physics ,Circular dichroism ,Radiation ,Myoglobin ,business.industry ,Chemistry ,Circular Dichroism ,Analytical chemistry ,Synchrotron radiation ,Fluorescence ,Fluorescence spectroscopy ,Spectrometry, Fluorescence ,Beamline ,Luminescent Measurements ,Humans ,Optoelectronics ,Spectrophotometry, Ultraviolet ,Time-resolved spectroscopy ,Luminescence ,Spectroscopy ,business ,Instrumentation ,Serum Albumin ,Synchrotrons - Abstract
The new 4B8 beamline provides UV-VUV light in the wavelength range from 360 to 120 nm. It uniquely enables two kinds of spectroscopy measurements: synchrotron radiation circular dichroism spectroscopy and VUV excited fluorescence spectroscopy. The former is mainly used in protein secondary structure studies, and the latter in VUV excited luminescent materials research. Remote access to fluorescence measurement has been realised and users can collect data online. Besides steady-state measurements, fluorescence lifetime measurements have been established using the time domain method, while a laser-induced temperature jump is under development for protein folding dynamics using circular dichroism as a probe.
- Published
- 2009
35. Development of a type of a one-dimensional position-sensitive scintillator–fiber detector for X-ray backscatter imaging
- Author
-
Long Wei, Guangzhi Sun, Cunfeng Wei, Ma Chuangxin, Feng Baotong, Ximeng Chen, Ke Li, Tianbao Zhang, Rensong Wang, Daowu Li, Hu Tingting, Zhiming Zhang, and Shuai Lei
- Subjects
Physics ,Nuclear and High Energy Physics ,Photomultiplier ,Backscatter ,Physics::Instrumentation and Detectors ,business.industry ,Detector ,X-ray ,Scintillator ,Lyso ,Optics ,High Energy Physics::Experiment ,Diffuse reflection ,Fiber ,business ,Instrumentation - Abstract
We have developed a one-dimensional position-sensitive detector (1-D PSD) for X-ray backscatter imaging which had a scintillator-fiber- position-sensitive photomultiplier (PSPMT) structure. Scintillators of the detector were covered by diffused reflection material. Teflon and the fiber of the detector was covered by mirror reflection material an aluminum foil. The detector was composed of a 1 x 25 LYSO array which was coupled with 25 plastic fibers. Another end of these fibers was twisted into a 5 x 5 array and coupled with a PSPMT R8520. The detector element's area was 4.2 x 20 mm(2) and the position resolution was 4.2 mm. We tested the positioning histogram of the detector set up an X-ray backscatter imaging system, and obtained an X-ray backscatter image from it. (C) 2008 Elsevier B.V. All rights reserved.
- Published
- 2008
36. Development of a PET Insert for simultaneously small animal PET/MRI
- Author
-
Zhiming Zhang, Long Wei, Wang Yingjie, P. L. Wang, Baotong Feng, Liu Shuangquan, Chai Pei, and Daowu Li
- Subjects
Radiation ,Materials science ,Coaxial cable ,business.industry ,Detector ,Biomedical Engineering ,Signal ,Imaging phantom ,Lyso ,law.invention ,Silicon photomultiplier ,Optics ,law ,Meeting Abstract ,Electromagnetic shielding ,Radiology, Nuclear Medicine and imaging ,Tomography ,business ,Nuclear medicine ,Instrumentation - Abstract
PET/MR is a new multi-modality imaging system which provide both structural and functional information with good soft tissue imaging ability and no ionizing radiation. In recent years, PET/MR is under major progress because of the development of silicon photomultipliers (SiPM). The goal of this study is to develop a MRI compatible PET insert based on SiPM and LYSO scintillator. The PET system was constituted by the detector ring, electronics and software. The detector ring consists of 16 detector module. The inner diameter of the ring was 151 mm, the external diameter was 216 mm, which was big enough for small animal research, e.g. rat, rabbit and tupaia. The sensor of each module was 2*2 SensL SPMArraySL, coupled with an array of 14 x 14 LYSO crystals, each crystal measuring 2 mm x 2 mm 10 mm. The detector was encapsulated in a copper box for light and magnetic shielding. Resister charge multiplexing circuit was used in the front end electronics. Each detector output 8X and 8Y position signals. One summed timing signal was extracted from the common cathode of all 64 channels. All these signals were transmitted to digital electronic board by a 3 m long coaxial cable from inside of the MR to the outside. Each digital electronic board handled 8 detector modules based on FPGA to obtain the timing, position and energy information of a single event. And then these single events were sent to the coincidence processing board to produce coincidence packets which are prepared for further processing. A 0.2mCi 68Ge line source was used to do the preliminary imaging test. The image was reconstructed by 3D-OSEM algorithm. The initial result proved the system to be feasible as a PET. FDG phantom imaging and simultaneous PET/MR imaging are in progress.
- Published
- 2015
37. Virtual instrument for controlling and monitoring digitalized power supply in SSRF
- Author
-
Han-Jiao Chen, Ruren Xu, T Shen, Jiang Tang, and Daowu Li
- Subjects
Nuclear and High Energy Physics ,Source code ,Serial communication ,Computer science ,business.industry ,media_common.quotation_subject ,Electrical engineering ,Insulated-gate bipolar transistor ,Converters ,Power (physics) ,Nuclear Energy and Engineering ,Embedded system ,Software design ,Digital control ,business ,Pulse-width modulation ,media_common - Abstract
The Shanghai Synchrotron Radiation Facility (SSRF) needs extremely precise power supplies for their various magnets. A digital controller is being developed for the power converters of the SSRF power supply (PS). In the digital controller, a fully digital pulse-width modulator (PWM) directly controls the power unit insulated gate bipolar transistor (IGBT) of the PS. A program in Lab VIEW language has been developed to control and monitor the digital PS via serial communication (RS232) from a PC and to modify its parameters as well. In this article, the software design of the virtual instrument for controlling and monitoring digitalized PS and its associated functions are described, and the essential elements of the program graphical main-VI and sub-VI source code are presented and explained. The communication protocol and the structure of the developed system are also included in this article.
- Published
- 2006
38. Analysis of transmission efficiency of SSRF electron beam transfer lines
- Author
-
Jianhui Hou, Guang-Hui Liu, Yu Han, and Daowu Li
- Subjects
Nuclear and High Energy Physics ,Materials science ,business.industry ,Transfer line ,Analytical chemistry ,Dynamic simulation ,Optics ,Nuclear Energy and Engineering ,Transmission (telecommunications) ,Magnet ,Transfer (computing) ,Cathode ray ,Trajectory ,Physics::Accelerator Physics ,business ,Beam (structure) - Abstract
In this article, the main factors which influence transmission efficiency of the SSRF electron beam transfer lines are described, including physical requirements for magnet system, vacuum system, beam diagnostic system, trajectory correction system, etc. The dynamic simulation calculation and transmission efficiency analysis of the SSRF electron beam transfer lines are presented, and the studies show that the design purpose of efficient beam transmission and injection will be achieved.
- Published
- 2006
39. Depth discrimination method based on a multirow linear array detector for push-broom Compton scatter imaging
- Author
-
Sun Shifeng, Baotong Feng, Zhou Wei, Xiaopan Jiang, Li Ting, Long Wei, Wang Yingjie, Cunfeng Wei, Zhu Meiling, ChuangXin Ma, Shuai Lei, Zhuang Kai, Xianchao Huang, Hu Tingting, Haohui Tang, Daowu Li, Zhiming Zhang, Chai Pei, Liu Yantao, and Yiwen Zhang
- Subjects
Physics ,Radiation ,Physics::Instrumentation and Detectors ,business.industry ,Detector ,Compton scattering ,Collimator ,Signal ,Sample (graphics) ,law.invention ,Linear array ,Optics ,law ,business ,Row - Abstract
A depth discrimination method is devised based on a multirow linear array detector for push-broom Compton scatter imaging. Two or more rows of detector modules are placed at different positions towards a sample. An improved parallel-hole collimator is fixed in front of the modules to restrict their fields of view. The depth information could be indicated by comparing the signal differences. In addition, an available detector and several related simulations using GEANT4 are given to support the method well.
- Published
- 2013
40. A scintillating plastic fiber array and multiplexer based 384-channel fast neutron spectrometer.
- Author
-
Liyang Sun, Kai Zhuang, Xiaoming Wang, Heng An, Fanjian Zeng, Mingjie Yang, Wei Zhou, YuXiong Xue, Zhiming Zhang, Yingjie Wang, Daowu Li, Baotong Feng, Peilin Wang, Xiaohui Li, Jiale Cai, Xiu Bo Qin, and Long Wei
- Subjects
NEUTRON counters ,PLASTIC fibers ,NEUTRONS ,SIGNAL processing ,SIMULATION methods & models - Abstract
Afast neutron detection system based on a scintillating plastic fiber array and multiplexerwas designed to measure the spectrum of fast neutrons ranged 10 MeV-100 MeV. With the method of nuclear recoil, the energy of incident neutron was determined by measuring the recoil proton track and deposited energy in scintillating plastic fibers. The detection system was composed of a scintillating plastic fiber array, 6 position sensitive photomultiplier tubes, and a high-density readout electronics based on the multiplexer. The scintillating plastic fiber array was made as a staggered structure with two kinds of fibers in different sizes (0.5 mm-square fiber and 3 mm-square fiber). The structure provided a wider detection energy range and better detection efficiency than arrays made with uniform plastic fibers. A dedicated digital electronics system was well designed to control the whole readout system to provide 384-channel signal processing. The detector had a 48 mm X 48 mm effective detection area and a mechanical size of 34 cm X 34 cm X 27 cm. In the simulation of the detector model performance, the system gave an energy resolution of 23%-35% for neutrons ranged 10MeV-100MeV. Experimental results showed that the detector had a good energy linearity and energy resolutions were, respectively, 35.82% at 14.817 MeV, 36.84% at 21.264 MeV, 35.90% at 23.069 MeV, and 32.90% at 24.220 MeV. The optimized prototype model had potential in increasing fast neutron detection performance. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
41. Investigation of the time performance of a LYSO array for TOF-PET
- Author
-
Junhui Liu, Zhiming Zhang, Jiong-Hui Xu, Daowu Li, Jin-Xing Cheng, Feng-Feng Cheng, Long Wei, and Baoyi Wang
- Subjects
Physics ,Nuclear and High Energy Physics ,Photomultiplier ,Discriminator ,medicine.diagnostic_test ,business.industry ,Detector ,Astronomy and Astrophysics ,Lyso ,Coincidence ,Full width at half maximum ,Optics ,Quality (physics) ,Positron emission tomography ,medicine ,business ,Instrumentation - Abstract
Positron Emission Tomography (PET) using time-of-flight information, which can greatly improve the quality of the reconstructed image, has recently become an exciting topic. In this work, 3.2 mm x3.2 tam x25 mm finger-like LYSO.crystals were used to make a 5x5 array, coupled to the Hamamatsu H8500 photomultiplier tube (PMT) as a detector. A fast leading-edge discriminator was designed for the LYSO-H8500 detector. Average coincidence time resolution FWHM of 330 ps was obtained for the LYSO detector with a reference BaF2 detector, whose time resolution for 511 keV gamma-rays was FWHM 150 ps. Time resolution FWHM of 294 Ps was calculated for the LYSO detector, and coincidence time resolution of FHWM 415 ps can be expected for two identical LYSO detectors.
- Published
- 2015
42. A TOF-PET Detector based on Quadrant-Sharing PMTs and Optimized Leading-edge Timing Method
- Author
-
Long Wei, Zhiming Zhang, Junhui Liu, Baoyi Wang, Xingzhong Cao, Wang Yingjie, Tianbao Zhang, and Daowu Li
- Subjects
Physics ,History ,Leading edge ,Photomultiplier ,Channel (digital image) ,business.industry ,Detector ,Constant fraction discriminator ,Lyso ,Coincidence ,Computer Science Applications ,Education ,Optics ,Histogram ,Electronic engineering ,business - Abstract
A time-of-flight positron emission tomography (TOF-PET) detector was developed based on a 6×9 LYSO array and four single channel photomultipliers (Hamamatsu R9800). Leading-edge timing circuit with optimized parameter was used instead of the constant fraction discriminator. The results showed that all 54 elements in the flood histogram could be identified clearly. The average coincidence resolving time was 402 ps FWHM.
- Published
- 2013
43. A highly active SERS sensing substrate: core–satellite assembly of gold nanorods/nanoplates
- Author
-
Jixue Wang, Weihong Xu, Daowu Li, Jiaxing Liu, and Guangchao Zheng
- Subjects
Nanotubes ,Materials science ,biology ,Mechanical Engineering ,Metal Nanoparticles ,Substrate (chemistry) ,Bioengineering ,Nanotechnology ,DNA ,General Chemistry ,Spectrum Analysis, Raman ,biology.organism_classification ,Catalysis ,Core (optical fiber) ,symbols.namesake ,Mechanics of Materials ,symbols ,General Materials Science ,Satellite (biology) ,Nanorod ,Gold ,Electrical and Electronic Engineering ,Raman spectroscopy ,Biosensor - Abstract
Regiospecific core-satellite assembly of gold nanoplates (AuNPs)/gold nanorods (AuNRs) can be fabricated via ss-DNA hybridization. SERS behavior of the DNA driven assembly has been explored from inducing transition between para-ATP and DMAB through plasmon-assisted catalysis, suggesting that the core-satellite assembly can be utilized as highly active optical substrate. Moreover, a Raman label tagged thymine-rich DNA functionalized AuNRs/AuNPs assembly can be employed as in situ SERS sensing of mercury ions at the ultrasensitive ppt level, which indicates that the core-satellite assembly is appropriate as a versatile SERS substrate for the application of optical chemical or biosensing.
- Published
- 2013
44. Ability of the Positron Emission Mammography system, PEMi, in detection of millimeter-sized lesions.
- Author
-
Lin Li, Xiaoyue Gu, Daowu Li, Xianchao Huang, Pei Chai, Baotong Feng, Peilin Wang, Mingkai Yun, Dong Dai, Zhiming Zhang, Pengfei Yin, Wengui Xu, and Long Wei
- Published
- 2013
- Full Text
- View/download PDF
45. Developing VUV spectroscopy for protein folding and material luminescence on beamline 4B8 at the Beijing Synchrotron Radiation Facility.
- Author
-
Ye Tao, Yan Huang, Zhenghua Gao, Hao Zhuang, Aiyu Zhou, Yinglei Tan, Daowu Li, and Shuaishuai Sun
- Subjects
ULTRAVIOLET spectroscopy ,X-ray spectroscopy ,FLUORESCENCE spectroscopy ,SYNCHROTRON radiation ,PROTEIN folding ,DICHROISM - Abstract
The new 4B8 beamline provides UV-VUV light in the wavelength range from 360 to 120 nm. It uniquely enables two kinds of spectroscopy measurements: synchrotron radiation circular dichroism spectroscopy and VUV excited fluorescence spectroscopy. The former is mainly used in protein secondary structure studies, and the latter in VUV excited luminescent materials research, Remote access to fluorescence measurement has been realised and users can collect data online. Besides steady-state measurements, fluorescence lifetime measurements have been established using the time domain method, while a laser-induced temperature jump is under development for protein folding dynamics using circular dichroism as a probe. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
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