分类： 物理学 >> 核物理学 提交时间： 2025-02-09
xu, Mr. Qin
Dong, Mr. Yuchen 董雨晨
Kreuzpaintner, Prof. Wolfgang
Li, Mr. Xiao-Mian
Meng, Mr. Xin-Pei
Musgrave, Prof. Matthew
Tian, Dr. Long
Xiong, Prof. Xiao-Min
Ye, Mr. Fan
Zhang, Dr. Junpei 张俊佩
Wang, Prof. Tianhao 王天昊
Tong, Prof. Xin 童欣
摘要： A new prototype adiabatic RF-flipper was recently developed at the China Spallation Neutron Source. The prototype device was calibrated at the test beamline BL-20 over a wavelength range of 0.6 Å to 5.5 Å, and achieved a flipping efficiency of 97% for neutron wavelengths above 4 Å. During the development of the adiabatic RF-flipper, finite element method and spin transformation simulations were applied to precisely determine the magnetic field configuration and neutron spin-flip efficiency. This work demonstrates the design and optimization of the adiabatic RF-flipper for a specific neutron beamline, where the dependence of the flipping efficiency on neutron wavelength can be analyzed through simulation and numerical calculation for pulsed neutron beams.
分类： 物理学 >> 核物理学 提交时间： 2024-12-27
xu, Mr. Qin
Dong, Mr. Yuchen 董雨晨
Kreuzpaintner, Prof. Wolfgang
Li, Mr. Xiao-Mian
Meng, Mr. Xin-Pei
Musgrave, Prof. Matthew
Tian, Dr. Long
Xiong, Prof. Xiao-Min
Ye, Mr. Fan
Zhang, Dr. Junpei 张俊佩
Wang, Prof. Tianhao 王天昊
Tong, Prof. Xin 童欣
摘要： A new prototype adiabatic RF-flipper was recently developed at the China Spallation Neutron Source. The prototype device was calibrated at the test beamline BL-20 over a wavelength range of 0.6 Å to 5.5 Å, and achieved a flipping efficiency of 97% for neutron wavelengths above 4 Å. During the development of the adiabatic RF-flipper, finite element method and spin transformation simulations were applied to precisely determine the magnetic field configuration and neutron spin-flip efficiency. This work demonstrates the design and optimization of the adiabatic RF-flipper for a specific neutron beamline, where the dependence of the flipping efficiency on neutron wavelength can be analyzed through simulation and numerical calculation for pulsed neutron beams.
分类： 核科学技术 >> 裂变堆工程技术 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要： In recent years, neutrons have been studied for application in fields such as material analysis and boron neutron capture therapy. To create a compact shield for these facilities, a neutron shield concrete is developed. Verifying the homogeneity of the concrete is important to ensure adequate shielding performance. In this research, neutron radiography images of the concrete are taken using the Thermal Neutron Radiography Facility (TNRF) of the JRR-3 research reactor, and the transmission ratio of the thermal neutrons were estimated. The results showed that the transmission ratio of the concrete was almost the same at each depth.
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： 2024-12-16
wang, Dr. haitao
Zhang, Prof. Yan
Liu, Mr. Chi
Xu, Mr. Jian-Qiang
Zhang, Dr. Li-Jiao
LIU, Prof. Zhi-feng
Zhang, Dr. Xiongjie
Chen, Dr. Rui
Liu, Dr. Qi
Wang, Dr. Ren-Bo
Zhou, Mr. Shumin
Tang, Prof. Bin
摘要： The domestically developed prompt fission neutron uranium logging(PFNUL) instrument for uranium exploration represents a significant advancement in China deep uranium mining efforts, though it comes with considerable challenges and complexity. This paper presents the development of a new prompt fission neutron uranium logging instrument(named UNL4) , integrates a domestic D-T neutron generator, two 3He proportional detectors, a lanthanum bromide (LaBr3) gamma-ray detector, and digital multi-channel pulse amplitude analyzer. The near 3He detector is shielded with 1mm of Cadmium (Cd) and 5mm of high-density polyethylene(HDPE), enabling efficient epithermal neutron detection, while the far 3He detector measures thermal neutron. The LaBr3 detector is employed for gamma-ray detection, primarily originating from uranium decay. High-speed ADC and FPGA technologies were used to achieve rapid acquisition and transmission of both dual neutron time spectra and gamma spectra.Moreover, this paper proposes a fast signal shaping method, which reduces the dead time effect in ^3He detectors on neutron time spectra. Experiments conducted in standard model boreholes with varying uranium content demonstrated a strong linear relationship between the epithermal-to-thermal neutron ratio (E/T) and uranium content, with a fitting coefficient of R2>0.999, confirming the instruments accuracy. The E/T value repeatability, both in short-term (3.16% RSD) and long-term (1.2% RSD) measurements, showed excellent stability. In addition, the instrument demonstrated good performance at neutron logging speeds of 0.3∽3 m/min (E/T values) and gamma logging speeds of 1∽10 m/min. By conducting measurements in two ore sections of the PU model with lithium contents of 87.1 ppm and 45.6 ppm, the RD is less than about 10% in both logging cases, meeting the requirements for engineering applications. This marks the first successful development of a neutron logging instrument for uranium exploration based on a domestic neutron generator, signifying an important contribution to uranium resource exploration.
分类： 核科学技术 >> 辐射物理与技术 提交时间： 2025-03-11
摘要： With the increasing demand for controllable source logging, research on data-processing algorithms that meet accuracy requirements has become key to the development of controllable-source-logging tools. This study theoretically derives the relationship between the formation density and inelastic gamma count rate to investigate the data-processing methods for deuterium-tritium (D-T) source neutron-gamma density logging while drilling. Then, algorithms for the net inelastic gamma count-rate extraction and neutron transport correction are studied using Monte Carlo simulations. A new method for fast-neutron effect identification and additional correction is proposed to improve the density-calculation accuracy of gas-filled and heavy-mineral formations. Finally, the effectiveness and accuracy of the proposed data-processing methods are verified based on simulated and measured data. The results show that the density-calculation accuracy of water-bearing conventional formations in simulated data is ±0.02g/cm3. The accuracy of gas-filled and heavy-mineral formations after the additional fast-neutron effect correction is ±0.025g/cm3. For the measured data from the actual tool, the algorithms per form well in the density calculation. The density results obtained using the processing algorithms are consistent with the density data provided by NeoScope. Therefore, the D-T source neutron-gamma density-logging algo rithms proposed in this study can obtain relatively accurate data-processing results for a variety of formations. This study provides technical support for engineering applications and the development of logging tools for controllable-source neutron-density logging.
分类： 物理学 >> 核物理学 提交时间： 2025-05-27
Tian, Dr. Long
Gao, Dr. Han
Wang, Prof. Tianhao 王天昊
Teng, Mr. Haiyun
tang, Dr. jian
Zheng, Mr. Qingbo
Zuo, Dr. Taisen
Cui, Dr. Tengfei
Wang, Mr. Bin
xu, Mr. Qin
Qiu, Mr. Yongxiang
Dong, Mr. Yuchen 董雨晨
Zheng, Mr. Yujie
Qin, Dr. Zecong
Han, Dr. Zehua
Zhang, Dr. Junpei 张俊佩
Cheng, Dr. He
Tong, Prof. Xin 童欣
摘要： Polarization-analyzed small-angle neutron scattering (PASANS) is an advanced technique that enables the selective investigation of magnetic scattering phenomena in magnetic materials and distinguishing coherent scattering obscured by an incoherent background, making it particularly valuable for cutting-edge research. The successful implementation of PASANS in China was achieved for the first time at the newly commissioned Very Small Angle Neutron Scattering (VSANS) instrument at the China Spallation Neutron Source (CSNS). This technique employs a combination of a double-V cavity supermirror polarizer and a radio frequency (RF) neutron spin flipper to manipulate the polarization of the incident neutrons. The scattered neutron polarization is stably analyzed by a specially designed in-situ optical pumping 3He neutron spin filter, which covers a spatially symmetric scattering angle coverage of about 4.8○. A comprehensive PASANS data reduction method, aimed at pulsed neutron beams, has been established and validated with a silver behenate powder sample, achieving a maximum momentum transfer coverage of approximately 0.25 Å-1.
分类： 物理学 >> 核物理学 提交时间： 2025-05-23
Nazarov, Dr. Kuanysh
Kulikbayeva, Ms. Dana
Nurulin, Mr. Rassim
Mukhametuly, Dr. Bagdaulet
Bekbayev, Dr. Askhat
Kenessarin, Mr. Murat
Arynbek, Mr. Yersultan
Bodnarchuk, Dr. Viktor
Churakov, Mr. Andrey
Zernin, Mr. Nikolay
Murashkevich, Mrs. Svetlana
Petukhova, Ms. Tatiana
Avdeed, Dr. Mikhail
摘要： The concept of the new experimental setup - neutron reflectometer ARMAN (Almaty Reflectometer of MonochromАtic Neutrons) is presented. The instrument is to be placed at beamline 4 with thermal neutrons at the WWR-K reactor of the Institute of Nuclear Physics, Almaty, Kazakhstan. The instrument features a horizontal scattering geometry with a vertically oriented sample with the size of beam 2 50 mm2. The reflectometer will operate with monochromatic neutron beam in two modes: with and without polarization of the incident beam. The monochromatization will be provided by a double-crystal monochromator of pyrolytic graphite plates with the working wavelength range of 1.8-2.8 Å and expected resolution ∆λ/λ in the range of 1-3%. The schematics and main elements together with the numerical estimates of the expected neutron flux in different places of the beamline are discussed.
分类： 核科学技术 >> 粒子加速器 提交时间： 2021-12-31
Chen, Jun-Yang
Tong, Jian-Fei
Hu, Zhi-Liang
Han, Xue-Fen
Tang, Bin
Yu, Qian
Zhang, Rui-Qiang
Zhao, Chong-Guang
Xu, Jun
Fu, Shi-Nian
Zhou, Bin
Liang, Tian-Jiao
摘要： An accelerator-based Boron Neutron Capture Therapy (AB-BNCT) experimental facility called D-BNCT01 has been recently completed and is currently able to generate a high-intensity neutron beam for BNCT related research. In this study, we perform several experiments involving water phantoms to validate the Monte Carlo simulation results and analyze the neutron beam characteristics. According to our measurements, D-BNCT01 may generate a neutron flux about 1.2×108 n/cm2/s at the beam port using a 5 kW proton beam. Our results, also show that the thermal neutron flux depth distribution inside the water phantom is in good agreement with simulations. We conclude that D-BNCT01 may be effectively employed for BNCT research.
分类： 物理学 >> 核物理学 提交时间： 2023-06-06
摘要： β衰变半衰期和β延迟中子发射（βn）在核物理和核能等基础科学和工业应用的发展中具有重要意义，其中β−衰变起着重要作用。许多理论模型已经被提出来描述β-衰变的半衰期，而对βn的系统研究仍然很少。本文旨在通过解析公式研究了β−-衰减半衰期和βn概率，并与实验数据进行了比较。通过考虑衰减能量、凹凸度和壳效应等主要因素，提出了β−-衰减性质的解析公式。采用自助法同时评价计算的总不确定性，由统计量和系统不确定性组成。评估了中子富区的β−-衰变半衰期、βn概率和相应的不确定性。实验中的半衰期被很好地再现了。更多的预测也提出了理论的不确定性，这有助于更好地理解实验结果和理论结果之间的差异
分类： 物理学 >> 核物理学 提交时间： 2025-03-12
摘要： Research experiments regarding radiation effects demand the precise simulation of diverse radiation environments. In both the space and nuclear sectors, hybrid radiation fields with varying neutron-gamma ratios are prevalent. This study puts forward a convenient approach to regulate the neutron-gamma ratio and verifies its precision through experimental measurements at the 100MeV proton cyclotron of the China Institute of Atomic Energy. To achieve accurate and adjustable regulation of the neutron-gamma ratio within a range spanning from a few to several hundred, a neutron-gamma ratio regulator has been developed. The regulator was composed of different shielding materials with varying thicknesses and settled on the quasi-monoenergetic neutron beam line. The incident neutrons were generated by bombarding a lithium target with protons. Beam detection and calibration experiments were conducted, which demonstrated the effectiveness and superiority of generating hybrid radiation with adjustable neutron-gamma ratios in accelerator-based neutron fields.
分类： 物理学 >> 核物理学 提交时间： 2025-01-27
Li, Dr. Xinxiang
Liu, Dr. Longxiang
Jiang, Dr. Wei
Chen, Miss YaJv
Ren, Dr. Jie
Wang, Prof. Hongwei
Fan, Prof. Gongtao
Luo, Dr. Wen
Feng, Dr. Song
XIe, Mr. Wen
Lin, Mr. ZiAn
Jiang, Miss Ting
Yang, Mr. GaoLe
An, Dr. ZhenDong
Li, Dr. Xankai
Liao, Mr. ZhouJi
Xue, Ms. Jieming
Li, Miss XinYu
Peng, Miss NingXin
Wang, Mr. Dexin
摘要： \ce{^{147,149}Sm} are slow neutron capture (s-process) nuclides in nuclear astrophysics, whose (n,\gamma) cross-section are the important input parameters in nucleosynthesis net calculation in the Samarium (Sm) region. Additionally, \ce{^{149}Sm} is a fission product of \ce{^{235}U} with 1\% yield, and its neutron resonance parameters play a critical role in reactor neutronics. According to the available nuclear evaluation databases, significant disagreement have been observed in the resonance peaks of \ce{^{147,149}Sm} (n,\gamma) cross section data within the energy range of 20-300 eV. In this study, the neutron capture cross section of the natural Samarium target was measured at the back-streaming white neutron beamline of China Spallation Neutron Source. The neutron capture yield was obtained and the neutron resonance parameters for \ce{^{147}Sm} at 107.0， 139.4， 241.7， and 257.3 eV and \ce{^{149}Sm} at 23.2, 24.6, 26.1, 28.0, 51.5, 75.2, 90.9, 125.3, and 248.4 eV were extracted using the SAMMY code based on R-matrix theory. For the parameters \Gamma_n and \Gamma_\gamma in these energies of \ce{^{147,149}Sm}, the percentages consistent with the results of the CENDL-3.2, ENDF/B-VIII.0, JEFF-3.3, JENDL-4.0, and BROND-3.1 database are 27\%, 65\%, 65\%, 42\%, and 58\%, respectively. Meanwhile, 27\% of the results were inconsistent with them included in any of the major libraries. This work enrichis the experimental data of \ce{^{147,149}Sm} neutron capture resonance and helps to clarify the differences between different evaluation databases at the above energies.
分类： 物理学 >> 核物理学 提交时间： 2025-01-17
Dawei Si
Sheng Xiao
Zhi Qin
Junhuai Xu
Baiting Tian
Boyuan Zhang
Haojie Zhang
Dong Guo
Yijie Wang
Xiaobao Wei
Yibo Hao
Zengxiang Wang
Tianren Zhuo
Chunwang Ma
Yuansheng Yang
Xianglun Wei
Herun Yang
Peng Ma
Limin Duan
Fangfang Duan
摘要： The neutron-neutron (nn) correlation function has been measured in 25 MeV/u ^{124}Sn+^{124}Sn reactions.Using the Lednick\’y-Lyuboshitz approach, the nn scattering length and effective range (f_{0}^{nn}, d_{0}^{nn}), as well as the reduced space-time size R^{(0)} of the neutron emission source are simultaneously extracted as (18.9^{+1.3}_{-1.2} fm, 1.9^{+1.3}_{1.0} fm) and 4.12 \pm 0.12 fm, respectively. The measured nn scattering length is consistent with the results obtained in the low-energy scattering ^{2}{\rm H}(\pi^{-},\gamma)2n, indicating heavy-ion collisionscan serve as an effective approach for measuring nn interactions and further investigating the charge symmetry breaking of nuclear force. The space-time size extracted from momentum-gated correlation functions exhibits clear dependence on the pair momentum, with R^{(0)}=2.8 \pm 0.1 fm and 4.9 \pm 0.2 fm being determined for the high and low momentum neutrons, respectively.
分类： 物理学 >> 核物理学 提交时间： 2023-05-31
摘要： In this work we perform a Bayesian inference of the crust-core transition density t of neutron stars based upon the neutron-star radius and the neutron-skin thickness data within a thermodynamicalmethod. The uniform and Gaussian distributions for the t prior are adopted in the Bayesianapproach. It has a larger probability to have values higher than 0.1 fm3 for t as the uniform priorand the neutron-star radius data are used. We found that this is controlled by the curvature Ksym ofthe nuclear symmetry energy. This phenomenon will not happen if Ksym is not extremely negative,i.e., Ksym > -200 MeV. The obtained t is 0.075+0.005-0.01fm^3 at 68% confifidence level when both the neutron-star radius and the neutron-skin thickness data are taken into account. The strongly anti-correlations between t and the slope L, curvature of the nuclear symmetry energy are observed.The dependence of the three L-Ksym correlations predicted in the literature on the crust-core densityand pressure is quantitatively investigated. The most probable value of 0.08 fm^3 for t is obtainedfrom the L-Ksym relation raised by Holt et al. and the larger values are preferred by the other tworelations.
分类： 物理学 >> 核物理学 提交时间： 2025-03-28
Peng, Dr. Chao
Ma, Dr. Teng
Zhang, Dr. Hong
Lei, Dr. Zhifeng
Zhang, Dr. Zhangang
Yu-Juan, Dr. He
Huang, Prof. Yun
摘要： The radiation-induced single event burnout (SEB) is observed for SiC MOSFETs by conducting proton and spallation neutron irradiation. Proton irradiation at different energies indicates that the SEB cross-section increases with the increase of proton energy. Under different bias voltages, the SEB cross-section of protons with energies of 100 MeV and above will exceed that of spallation neutrons. The atmospheric neutron SEB failure rates of SiC MOSFETs are calculated based on the proton-induced and neutron-induced SEB cross-sections, respectively. The failure rates calculated by the two different methods are consistent, with the error between the two results being less than 49%. The information of the secondary ions produced by spallation neutron and proton is obtained through Monte Carlo simulations. The simulation results imply that the SEB caused by protons and spallation neutrons is strongly correlated with the ionizing energy deposition of their secondary ions from nuclear reactions. As the proton energy increases, the number of secondary ion products with sufficient energy deposition to induce SEB increases. The magnitude of the SEB cross-sections for spallation neutrons and protons also depends on the number of secondary particles that deposit energy above the threshold energy.
分类： 核科学技术 >> 辐射物理与技术 提交时间： 2024-12-04
摘要： measurement method used to determine the formation poros-ity.The americium-beryllium(Am-Be)source is commonlyusedforconventionalporositymeasurements.However,theypose potential risks to safety,health, and the environment [14].Researchershavestudiedsubstitutionchemicalsourceswith deuterium-deuterium (D-D) neutrons [5-7]. However,theneutronyieldofD-Dneutronsourcesisrelativelylowwhich restrictstheir application[8,9]In2005,theoilfieldservicescompanySchlumberger(nowSLB)began using a deuterium-tritium(D-T) neutron sourcefor compensated thermal neutron porosity logging[10]Compared to the chemical source, the D-T neutron sourcehas a higher neutron yield,higher neutron energy of 14 MeV,and a longer slowing-down length of the neutron; thus,D-Tneutron logging can detect more thermal neutrons and has ahigher detection accuracy.Nevertheless, neutron slowing-down is facilitated by in-elastic scattering owing to the higher energy of neutronsConsequently, the D-T neutron recording exhibits reducedsensitivitytoporositycomparedtothechemicalsource[11.12],asmeasuredby theconventionalneutronporosityinter-pretation model founded on the Am-Be source[13-15].ods have been proposed to improve the porosity sensitivityof D-T neutron logging. The near and far thermal neutroncountswere correctedusing thedensitycorrectionfunction,and the modified thermal neutron counting ratio was consid-ered tobe only associated with the hydrogen-containing in-dex[16].Further,thedensity correctionmethods were sum-marized to modify the thermal neutron counting ratio andstudied by MC simulation [17]. The relationship of slowing-downlengthofneutronsbetween theformationdensityandhydrogen index was deduced and numerically simulated[18].Basedondatafromthestandardcalibrationexperimentandactuallogging[19,20],itwas verified that thedensitycorrec-tion results were consistent with the isotopic neutron source.Inaddition,the slowing-downlengthoftheD-Tneu-tronsourcecanbeconvertedintothatoftheAm-Besource.Onemethodinvolvestherelationshipbetweentheneutronslowing-downlength,capturingofthecross-section,andden-sity to predict the counting ratio[21]. The second involves thecombination of the two-group diffusion theory with the for-mation density, reaction cross-section, and neutron slowing-down length [22].
分类： 物理学 >> 核物理学 提交时间： 2024-01-05
YanYan Ding
YangBo Nie
Yue Zhang
ZhiJie Hu
Qi Zhao
HuanYu Zhang
KuoZhi Xu
ShiYu Zhang
XinYi Pan
ChangLin Lan
Jie Ren
XiChao Ruan
摘要： A benchmark experiment on 238U slab samples was conducted using a deuteriumtritium neutron source at the China Institute of Atomic Energy. The leakage neutron spectra within energy levels of 0.816 MeV at 60 and 120 were measured using the time-of-flight method. The samples were prepared as rectangular slabs with a 30 cm square base and thicknesses of 3, 6, and 9 cm. The leakage neutron spectra were also calculated using the MCNP-4C program based on the latest evaluated files of 238U evaluated neutron data from CENDL-3.2, ENDF/B-VIII.0, JENDL-5.0, and JEFF-3.3. Based on the comparison, the deficiencies and improvements in 238U evaluated nuclear data were analyzed. The results showed the following. (1) The calculated results for CENDL-3.2 significantly overestimated the measurements in the energy interval of elastic scattering at 60 and 120. (2) The calculated results of CENDL-3.2 overestimated the measurements in the energy interval of inelastic scattering at 120. (3) The calculated results for CENDL-3.2 significantly overestimated the measurements in the 38.5MeV energy interval at 60 and 120. (4) The calculated results with JENDL-5.0 were generally consistent with the measurement results.
分类： 物理学 >> 核物理学 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要： We report our recent progress on the nuclear symmetry energy probe, which is called the isobaric yield ratio difference (IBD), and its application in neutron density determination in experiments. The results obtained by the IBD, from which the isobaric yields in the measured 140 A MeV 40, 48Ca + 9Be and 58,64Ni + 9Be reactions, and the calculated 80 A MeV 38-52Ca + 12C reactions by using a modified statistical abrasion-ablation model, show the sensitivity of the IBD to the density differences between reactions.
分类： 物理学 >> 核物理学 提交时间： 2023-06-07
Zhang, Lianxin
Chen, Size
Zhang, Zaodi
Li, Taosheng
Peng, Chuan
Ren, Lei
Zhang, Rui
Xiao. Dan
Zhang. Yong
摘要： Owing to the immobility of traditional reactors and spallation neutron sources, the demand for compact thermal neutron radiography (CTNR) based on accelerator neutron sources has rapidly increased in industrial applications. Recently, thermal neutron radiography experiments based on a D-T neutron generator performed by Hefei Institutes of Physical Science indicated a significant resolution deviation between the experimental results and the values calculated using the traditional resolution model. The experimental result was up to 23% lower than the calculated result, which hinders the achievement of the design goal of a compact neutron radiography system. A GEANT4 Monte Carlo code was developed to simulate the CTNR process, aiming to identify the key factors leading to resolution deviation. The effects of a low collimation ratio and high-energy neutrons were analyzed based on the neutron beam environment of the CTNR system. The results showed that the deviation was primarily caused by geometric distortion at low collimation ratios and radiation noise induced by high 1 energy neutrons. Additionally, the theoretical model was modified by considering the imaging position and radiation noise factors. The modified theoretical model was in good agreement with the experimental results, and the maximum deviation was reduced to 4.22%. This can be useful for the high-precision design of CTNR systems.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-11-10
TiPei Li
ShaoLin Xiong
ShuangNan Zhang
FangJun Lu
LiMing Song
XueLei Cao
Zhi Chang
Gang Chen
Li Chen
TianXiang Chen
Yong Chen
YiBao Chen
YuPeng Chen
Wei Cui
WeiWei Cui
JingKang Deng
YongWei Dong
YuanYuan Du
MinXue Fu
GuanHua Gao
摘要： Finding the electromagnetic (EM) counterpart of binary compact star merger, especially the binary neutron star (BNS) merger, is critically important for gravitational wave (GW) astronomy, osmology and fundamental physics. On Aug. 17, 2017, Advanced LIGO and Fermi/GBM independently triggered the first BNS merger, GW170817, and its high energy EM counterpart, GRB 170817A, respectively, resulting in a global observation campaign covering gamma-ray, X-ray, UV, optical, IR, radio as well as neutrinos. The High Energy X-ray telescope (HE) onboard Insight-HXMT (Hard X-ray Modulation Telescope) is the unique high-energy gamma-ray telescope that monitored the entire GW localization area and especially the optical counterpart (SSS17a/AT2017gfo) with very large collection area (~1000 cm2) and microsecond time resolution in 0.2-5 MeV. In addition, Insight-HXMT quickly implemented a Target of Opportunity (ToO) observation to scan the GW localization area for potential X-ray emission from the GW source. Although Insight-HXMT did not detect any significant high energy (0.2-5 MeV) radiation from GW170817, its observation helped to confirm the nexpected weak and soft nature of GRB 170817A. Meanwhile, Insight-HXMT/HE provides one of the most stringent constraints (~10-7 to 10-6 erg/cm2/s) for both GRB170817A and any other possible precursor or extended emissions in 0.2-5 MeV, which help us to better understand the properties of EM radiation from this BNS merger. Therefore the observation of Insight-HXMT constitutes an important chapter in the full context of multi-wavelength and multi-messenger observation of this historical GW event.
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