分类： 物理学 >> 核物理学 提交时间： 2025-05-07
段, Dr. 州航
Han, Mr. Jifeng
Chen, Ms. Yangmei
Lin, Dr. Weiping
Liu, Dr. Xingquan
Long, Mr. Yiyang
Qu, Dr. Guofeng
Ren, Ms. Peipie
Wang, Mr. Penghui
Yi, Mr. Chuqi
Zhao, Dr. Chaoyang
摘要： A high-spatial-resolution cone-beam X-ray imaging system has been realized based on the micro spot X-ray source generated by a high-quality electron beam from a Scanning Electron Microscope (SEM). The diameter of the X-ray source was estimated to be 1.0 μm based on Geant4 simulation when the primary electron beam size is 10 nm, which is mainly determined by the electron injection range inside the copper target, and the X-ray source was found to follow double Gaussian distribution. The clear X-ray images of a 400-mesh copper mesh have been acquired, and the best spatial resolution of the system was tested to be 7.1 μm under magnification factor of 68.8. The X-ray imaging on distinct head regions of a Carebara diversa ant have been realized, the organs like the ant’s jaw and eyes were clearly shown, and the imaging range can be adjusted easily. These results demonstrate that this imaging system has high magnifications and precise spatial resolution, and is able to achieve clear and practical X-ray imaging for very small biological specimens.
分类： 物理学 >> 核物理学 提交时间： 2025-06-04
Yi, Mr. Chuqi
Han, Mr. Jifeng
Fan, Dr. Ruirui
Guo, Dr. Yuhang
He, Mr. Junhan
Lin, Dr. Weiping
Liu, Dr. Xingquan
Long, Mr. Yiyang
qian, Prof. sen 钱森
Qu, Dr. Guofeng
Song, Dr. Ruiqiang
Yi, Dr. Han
Wang, Dr. Zhigang
Zhao, Dr. Chaoyang
摘要： Cs2LiYCl6: Ce (CLYC) scintillator is sensitive to neutrons within a wide-energy range and has the potential to achieve wide-range neutron energy spectrum measurements. The direct neutron detection performance of a CLYC detector has been realized by utilizing the Back-n white neutron source at China Spallation Neutron Source (CSNS), where a 20 cm lead brick was designed to effectively shield the accompanying gamma flash from the neutron source. The detected neutron energy spectrum after passing through the lead brick is primarily distributed within the 0.1–300 MeV and exhibits identical four-peak structures, which are consistent with Geant4 simulation results. The peak energies of the 1st, 3rd, and 4th peaks match well, with the relative deviation being less than 6%. However, a large energy deviation has been found for the 2nd peak whose energy falls within the resonance energy region of lead, which indicates that the resonance reaction of lead might not be precisely simulated in Geant4. Due to the dominance of elastic scattering between neutrons and the main nuclides (6Li, 35Cl, 37Cl, 89Y, 133Cs, 140Ce) in the CLYC scintillator in the low-energy region, suppression has been found for reactions that are used for neutron detection reactions such as (n, p), (n, d), (n, t) and (n, α). This leads to a significant difference in overall intensity between the low-energy range within 0.1–3 MeV (1st and 2nd peaks) and the high-energy range within 5–64 MeV (3rd and 4th peaks). A large number of gamma signals were measured in the experiment, which were found to be prompt gamma rays generated from neutron reactions with CLYC, but not the associated gamma rays from the neutron source. This phenomenon is more pronounced for the high-energy region, these prompt gamma rays can be combined into the neutron pulses and render the neutron pulses to contain fast-decay components that originally only existed in gamma pulses, and further decrease the neutron gamma discrimination performance of CLYC. By establishing a wide-energy neutron response matrix entirely based on experimental measurements and utilizing the GRAVEL unfolding method, the white neutron energy spectrum in the range of 6–200 MeV was successfully unfolded. These results provide a critical reference for the accurate measurement and discrimination of neutron-gamma signals in radiation fields using CLYC detectors and indicate the feasibility of using CLYC detectors for wide-energy neutron spectrum measurements, highlighting its potential for applications in high-energy neutron experiments, space neutron detection, and other related fields.
分类： 物理学 >> 核物理学 提交时间： 2025-03-30
Long, Mr. Yiyang
Han, Mr. Jifeng
Chen, Ms. Yangmei
Hu, Mr. Peng
Liu, Mr. Chuang
Ren, Mr. Jing
Song, Mr. Ruiqiang
Wang, Mr. Ke
Yi, Mr. Chuqi
Yin, Mr. Shenghua
Wang, Mr. Penghui
Lin, Dr. Weiping
Liu, Dr. Xingquan
Qu, Dr. Guofeng
Ren, Ms. Peipie
Zhao, Dr. Chaoyang
qian, Prof. sen 钱森
摘要： Neutron and gamma imaging have continuously expanded applications in nuclear safety, national security, and materials characterization. The hit position reconstruction algorithm is a key issue that constrains the image fidelity and accuracy. This work has developed a two-dimensional planar neutron and gamma imaging system based on a monolithic lithium glass scintillator and a silicon photomultiplier array. The results from the three metrics position nonlinearity response, flood image uniformity, and useful field-of-view demonstrate that the proposed artificial neural network (ANN) method significantly advances over traditional reconstruction methods. Imaging results from both the ‘720’ and ‘SCU’ models confirm the ANN method’s superior reconstruction quality. In addition, the ANN method achieves a systematic neutron imaging spatial resolution of approximately 0.47 mm for the ‘T’ model. These algorithms are implemented in experimental imaging system, the ANN method maintains acceptable image quality although certain noise artifacts are found, confirming its applicability in both simulated and experimental settings. This work demonstrates that the ANN method significantly enhances positioning accuracy and computational efficiency, resulting in superior neutron/gamma imaging quality.
点击量
待评议
点击量
下载量
评论
