分类： 物理学 >> 核物理学 提交时间： 2025-07-09
Jiao, Dr. Pu
Hao, Dr. Zirui
Li, Dr. Zhicai
Sun, Dr. Qiankun
Liu, Dr. Longxiang
Xu, Dr. Hanghua
Zhang, Dr. Yue
Zhou, Miss Mengdie
Yang, Dr. Yuxuan
Jin, Dr. Sheng
Chen, Dr. Kaijie
Ye, Mr. Shan
Wang, Dr. Zhenwei
Wang, Dr. Yuting
Wei, Mrs. Hui-Ling
Fu, Dr. Yao
Wang, Prof. Hongwei
Fan, Prof. GongTao
Ma, Dr. Chun-Wang (Nuclear physics) 马春旺
摘要： To overcome the difficulty and expensive cost for some specific isotopic targets, a substitution method was proposed to measure the cross section of (γ, n) reactions. Considering that the natural copper element (natCu) only has 63Cu and 65Cu isotopes, the 65Cu(γ, n)64Cu reaction was taken as an example to test the substitution method. Using quasi-monoenergetic γ beams provided by the Shanghai Laser Electron Gamma Source (SLEGS) of the Shanghai Synchrotron Radiation Facility (SSRF), the natCu(γ, n) was measured from Eγ= 11.09 to 17.87 MeV. Furthermore, based on the 63Cu(γ, n) reaction measured using the same experimental setup at SLEGS, the 65Cu(γ, n)64Cu was extracted using the substitution method. The abundance variation of natural copper, showing a significant influence in the cross section, is also investigated. The results were compared to the existing experimental data measured by bremsstrahlung and positron annihilation in-flight sources, and the TALYS 2.0 predictions. The γ strength function (γSF) of 65Cu is obtained from the 65Cu(γ, n) data, and the reaction cross section of 64Cu(n, γ) was further calculated.
分类： 核科学技术 >> 辐射物理与技术 提交时间： 2025-05-23
Longxiang Liu
Gongtao Fan
Hongwei Wang
Hanghua Xu
Yue Zhang
Zirui Hao
Chuangye He
Pu Jiao
Shan Ye
Yuxuan Yang
Sheng Jin
Kaijie Chen
Qiankun Sun
Zhenwei Wang
Mengke Xu
XiangFei Wang
Mengjie Zhou
Yulong Chen
Chang Yang
摘要： A 3-inch × 4-inch LaBr3 detector was employed to characterize the energy distributions of quasi-monoenergetic 𝛾-rays generated at the Shanghai Laser Electron Gamma Source (SLEGS), part of the Shanghai Synchrotron Radiation Facility. Systematic calibration of the detector’s response was conducted at the China Institute of Atomic Energy using monoenergetic 𝛾-rays from (p,𝛾) nuclear reactions on LiF, 27Al, and 13C targets. Energy spectrum unfolding was performed through an iterative matrix inversion algorithm, employing the detector’s monoenergetic response functions as kernel elements in the linear equation system. This approach facilitated direct reconstruction of 𝛾-ray energy spectra from raw detector signals. Validation experiments comparing LaBr3 and BGO detector reconstructions under identical conditions revealed strong agreement between the two detection systems. The methodology successfully characterized 𝛾-ray beam energy profiles resulting from slant-scattering processes at SLEGS, demonstrating robust performance in complex analysis.
分类： 物理学 >> 核物理学 提交时间： 2025-04-20
Junhuai Xu
Qinglin Niu
Yuhao Qin
Dawei Si
Yijie Wang
Sheng Xiao
Baiting Tian
Zhi Qin
Haojie Zhang
Boyuan Zhang
Dong Guo
Minxue Fu
Xiaobao Wei
Yibo Hao
Zengxiang Wang
Tianren Zhuo
Chunwang Ma
Yuansheng Yang
Xianglun Wei
Herun Yang
摘要： The nucleons in nuclei form temporally correlated pairs in close proximity, called short range correlation (SRC), which plays a crucial role in understanding nuclear structure and the fundamental properties of dense nuclear matter. The consequence of SRC on heavy-ion collisions (HICs) has remained unexplored until now. In this paper, we identify neutron-proton bremsstrahlung γ-ray emission from HICs as a new indicator of SRC in nuclei. By observing the hardening of the bremsstrahlung γ-ray spectrum, which results from the increase of high-momentum components above the Fermi surface in nucleon momentum distributions, we precisely determine the SRC fraction in nuclei to be (21±7)% at 3σ confidence levels. Our experiment identifies the first direct and accurate signature of SRC in low-energy HICs, providing a new method to study the parton momentum distribution of nucleons in nuclei.
分类： 物理学 >> 核物理学 提交时间： 2025-04-15
Jiao, Dr. Pu
Hao, Dr. Zirui
Li, Dr. Zhicai
Sun, Dr. Qiankun
Liu, Dr. Longxiang
Xu, Dr. Hanghua
Zhang, Dr. Yue
Zhou, Miss Mengdie
Yang, Dr. Yuxuan
Jin, Dr. Sheng
Chen, Dr. Kaijie
Ye, Mr. Shan
Wang, Dr. Zhenwei
Wang, Dr. Yuting
Wei, Mrs. Hui-Ling
Fu, Dr. Yao
Wang, Prof. Hongwei
Fan, Prof. GongTao
Ma, Dr. Chun-Wang (Nuclear physics) 马春旺
摘要： To overcome the difffculty and expensive cost for some speciffc isotopic targets, a substitution method was proposed to measure the cross section of (γ, n) reactions. Considering that the natural copper element (natCu) only has 63Cu and 65Cu isotopes, the 65Cu(γ,n)64Cu reaction was taken as an example to test the substitution method. Using quasi-monoenergetic γ beams provided by the Shanghai Laser Electron Gamma Source (SLEGS) of the Shanghai Synchrotron Radiation Facility (SSRF), the natCu(γ, n) was measured from Eγ = 11.09 to 17.87 MeV. Furthermore, based on the previously measured 63Cu(γ, n) reaction using the same experimental setup at SLEGS, the 65Cu(γ, n)64Cu was extracted using the substitution method, which was compared to the existing experimental data measured by bremsstrahlung and positron annihilation in-ffight light sources, and the Talys2.0 toolkit predictions. The γ strength function (γSF) of 65Cu is obtained from the 65Cu(γ, n) data, and the reaction cross section of 64Cu(n, γ) was further calculated.
分类： 核科学技术 >> 辐射物理与技术 提交时间： 2025-04-07
Xiang-Fei Wang
Kai-Jie Chen
Hang-Hua Xu
Gong-Tao Fan
Zi-Rui Hao
Zhen-Wei Wang
Long-Xiang Liu
Yue Zhang
Sheng Jin
Qian-kun Sun
Zhi-Cai Li
Pu Jiao
Meng-Die Zhou
Yu-Long Shen
Meng-Ke Xu
Hong-Wei Wang
摘要： A Monte Carlo simulation code and an analytical calculation code for polarization study were developed at Shanghai Laser Gamma Source (SLEGS), employing the unique laser Compton slant scattering (LCSS) mode. The intensity of spatial distributions and its Stokes parameters are simulated for LCSS of linearly/circularly polarized laser photons and unpolarized relativistic electrons. The polarization degree of the incident photon is almost completely transferred to the scattered gamma rays for any incident angle. For a linearly polarized laser incident in a fixed direction, the direction of polarization of the scattered gamma-ray changes with the scattering angle. The measured polarization direction and size of the scattered gamma spatial distribution are in general agreement with the simulation in the linearly polarized laser case.
分类： 物理学 >> 核物理学 提交时间： 2025-03-06
摘要： A machine learning approach utilizing the Bayesian neural networks has been developed to predict the complete fusion cross sections of weakly bound nuclei. This method was trained and validated using 475 experimental data points from 39 reaction systems all induced by 6,7Li, 9Be and 10B. The constructed Bayesian neural network demonstrated a high degree of accuracy in evaluating the complete fusion cross sections. By comparing the predicted cross sections with those obtained from the single barrier penetration model, the suppression effect of 6,7Li and 9Be with stable nucleus was made a systematic analysis. In the cases of 6Li and 7Li, a less suppression was predicted at the relatively light mass targets than that found in heavy mass targets and a notably distinct dependence relationship was identified, suggesting that the predominant breakup mechanisms might change in different mass target regions. In addition, the minimum suppression factors are predicted to occur near the target nuclei with neutron closed shell.
分类： 物理学 >> 核物理学 提交时间： 2025-02-07
xu, Mr. jishao
Cao, Dr. Xiguang
Su, Dr. Ping
Hao, Mr. Yibo
Cheng, Mr. Gaoyi
Liao, Mr. Zhengli
Yin, Mr. Weifu
Jin, Mr. Yonghao
Wei, Dr. Xiaobao
Wang, Mr. Zengxiang
liu, Dr. yancheng
Zhang, Dr. GuoQiang
Zhuo, Mr. Tianren
Ge, Dr. Ren
Yang, Dr. Yanyun
Ma, Mr. Junbing
Wang, Dr. Kang
Xu, Dr. Shiwei
Bai, Mr. Zhen
Yang, Dr. Guo
摘要： In this study, a compact 16-channel integrated charge and current sensitive preamplifier, called CCPA, was developed for the large-scale detector array used in nuclear physics experiments. The CCPA is designed to achieve the pulse shape discrimination method for silicon detectors. The CCPA has a fast response of typically less than 6 ns for the pulse rise time and a low equivalent noise of 1.5 keV at zero input capacitance. Energy dynamic range and pulse decay time can be easily adjusted for different applications by changing the feedback capacitance Cf and resistance Rf. A good energy resolution of 26.87 keV was achieved for 5.486 MeV αparticles from $^{241}\text{Am}$. The pulse shape discrimination method was applied for the first time in the experiment carried out on the Radioactive Ion Beam Line in Lanzhou (RIBBL1), and the CCPA demonstrated high resolution and stability in beam experiments. The experiment has realized the identification of low energy α particles as low as 5 MeV by pulse shape discrimination method, as well as the hundreds MeV charged particle. It provides a new routine for high precision measurement of low energy charged particles emitted by light nuclear reactions.
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： 2025-01-20
摘要： A machine learning approach utilizing the Bayesian neural networks has been developed to predict the complete fusion cross sections of weakly bound nuclei. This method was trained and validated using 475 experimental data points from 39 reaction systems all induced by 6,7Li, 9Be and 10B. The constructed Bayesian neural network demonstrated a high degree of accuracy in evaluating the complete fusion cross sections. By comparing the predicted cross sections with those obtained from the single barrier penetration model, the suppression effect of 6,7Li and 9Be with stable nucleus was made a systematic analysis. In the cases of 6Li and 7Li, a less suppression was predicted at the relatively light mass targets than that found in heavy mass targets and a notably distinct dependence relationship was identified, suggesting that the predominant breakup mechanisms might change in different mass target regions. In addition, the minimum suppression factors are predicted to occur near the target nuclei with neutron closed shell.
分类： 物理学 >> 核物理学 提交时间： 2025-01-18
摘要： A machine learning approach utilizing the Bayesian neural networks has been developed to predict the complete fusion cross sections of weakly bound nuclei.This method was trained and validated using 475 experimental data points from 39 reaction systems all induced by $^{6,7}$Li, $^9$Be and $^{10}$B.The constructed Bayesian neural network demonstrated a high degree of accuracy in evaluating the complete fusion cross sections.By comparing the predicted cross sections with those obtained from the single barrier penetration model, the suppression effect of $^{6,7}$Li and $^9$Be with stable nucleus was made a systematic analysis.In the cases of $^{6}$Li and $^{7}$Li, a less suppression was predicted at the relatively light mass targets than that found in heavy mass targets and a notably distinct dependence relationship was identified, suggesting that the predominant breakup mechanisms might change in different mass target regions.In addition, the minimum suppression factors are predicted to occur near the neutron magic number nuclei.
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： 2025-01-16
xu, Mr. jishao
Cao, Dr. Xiguang
Su, Dr. Ping
Hao, Mr. Yibo
Cheng, Mr. Gaoyi
Liao, Mr. Zhengli
Yin, Mr. Weifu
Jin, Mr. Yonghao
Wei, Dr. Xiaobao
Wang, Mr. Zengxiang
liu, Dr. yancheng
Zhang, Dr. GuoQiang
Zhuo, Mr. Tianren
Ge, Dr. Ren
Yang, Dr. Yanyun
Ma, Mr. Junbing
Wang, Dr. Kang
Xu, Dr. Shiwei
Bai, Mr. Zhen
Yang, Dr. Guo
摘要： In this study, a compact 16-channel integrated charge and current sensitive preamplifier, called CCPA, was developed for the large-scale detector array used in nuclear physics experiments. The CCPA is designed to achieve the pulse shape discrimination method for silicon detectors. The CCPA has a fast response of typically less than 6 ns for the pulse rise time and a low equivalent noise of 1.5 keV at zero input capacitance. Energy dynamic range and pulse decay time can be easily adjusted for different applications by changing the feedback capacitance Cf and resistance Rf. A good energy resolution of 26.87 keV was achieved for 5.486 MeV αparticles from $^{241}\text{Am}$. The pulse shape discrimination method was applied for the first time in the experiment carried out on the Radioactive Ion Beam Line in Lanzhou (RIBBL1), and the CCPA demonstrated high resolution and stability in beam experiments. The experiment has realized the identification of low energy α particles as low as 5 MeV by pulse shape discrimination method, as well as the hundreds MeV charged particle. It provides a new routine for high precision measurement of low energy charged particles emitted by light nuclear reactions.
分类： 物理学 >> 核物理学 提交时间： 2025-01-07
Jiang, Mr. Xuan
SUN, Mr. Yazhou
Wang, Dr. Shitao
Sun, Prof. Zhiyu 孙志宇
Ma, Mr. Peng
Duan, Prof. Limin 段利敏
Lu, Mr. Fenhua
jin, Mr. shuya
Tang, Dr. Shuwen
Yu, Dr. Yuhong
Zhang, Dr. Xueheng
Xu, Dr. Xiaodong
ONG, Prof. HOOI-JIN
Yan, Mr. Duo
Fang, Ms. Fang
Zhang, Mr. Yongjie
Tu, Prof. Xiao lin
Wei, Dr. Xiaobao
Li, Mr. Zhiyao
Liu, Mr. Tuoqi
摘要： The multiwire drift chambers at the target area of the External Target Facility of CSR are constructed for tracking radioactive ion beams that enter and exit the target. Two drift chambers with a sensitive area of 8 × 8 cm2 are positioned upstream of the target, while another two drift chambers with a sensitive area of 16 × 16 cm2 are placed upstream of the target. The drift chambers were tested using 350 MeV/u 78Kr beams and cocktail secondary beams. To improve drift time precision, the time walk effect is corrected by using the measured energy. The impact of δ-rays on the multiplicity and spatial resolution is assessed using beams with various atomic number and different applied voltages. The optimal voltage to minimize the impact of δ-rays is obtained. An optimal spatial resolution of 35 μm for the drift chambers is achieved.
分类： 物理学 >> 核物理学 提交时间： 2024-12-17
Jiao, Dr. Pu
Hao, Dr. Zi Rui
Sun, Dr. Qiankun
Liu, Dr. Longxiang Xiang
Xu, Dr. Hanghua
Zhang, Dr. Yue
Zhou, Miss Mengdie
Li, Dr. Zhicai
Yang, Dr. Yuxuan
Jin, Dr. Sheng
Chen, Dr. Kaijie
Ye, Mr. Shan
Wang, Dr. Zhenwei
Wang, Dr. Yuting
Wei, Mrs. Hui-Ling
Fu, Dr. Yao
Wang, Prof. Hongwei
Fan, Prof. GongTao
Ma, Dr. Chun-Wang (Nuclear physics) 马春旺
摘要： Accurate Photoneutron cross section measurement of 27Al nuclei has an important impact on clarifying the differences in existing experimental data and improving the accuracy of the nuclear reaction rate calculation of 26Al in nuclear astrophysics. The photoneutron cross sections for the 27Al(γ, n) reaction, within the neutron separation energy 13.2 MeV to 21.7 MeV, has been meticulously measured employing a new Flat Efficiency Detector (FED) array at the Shanghai Laser Electron Gamma Source (SLEGS).
分类： 物理学 >> 核物理学 提交时间： 2024-12-06
Jiao, Dr. Pu
Hao, Dr. Zi Rui
Sun, Dr. Qiankun
Liu, Dr. Longxiang Xiang
Xu, Dr. Hanghua
Zhang, Dr. Yue
Zhou, Miss Mengdie
Li, Dr. Zhicai
Yang, Dr. Yuxuan
Jin, Dr. Sheng
Chen, Dr. Kaijie
Ye, Mr. Shan
Wang, Dr. Zhenwei
Wang, Dr. Yuting
Wei, Mrs. Hui-Ling
Fu, Dr. Yao
Wang, Prof. Hongwei
Fan, Prof. GongTao
Ma, Dr. Chun-Wang (Nuclear physics) 马春旺
摘要： Accurate Photoneutron cross section measurement of 27Al nuclei has an important impact on clarifying the differences in existing experimental data and improving the accuracy of the nuclear reaction rate calculation of 26Al in nuclear astrophysics. The photoneutron cross sections for the 27Al(γ, n) reaction, within the neutron separation energy 13.2 MeV to 21.7 MeV, has been meticulously measured employing a new Flat Efficiency Detector (FED) array at the Shanghai Laser Electron Gamma Source (SLEGS).
分类： 核科学技术 >> 辐射物理与技术 提交时间： 2024-05-11
摘要： Carbon-based nanomaterials have important research significance in various disciplines, such as compositematerials, nanoelectronic devices, biosensors, biological imaging, and drug delivery. Recently, the human andecological risks associated with carbon-based nanomaterials have received increasing attention. However, thebiosafety of carbon-based nanomaterials has not been investigated extensively. In this study, we used differenttypes of carbon materials, namely, graphene oxide (GO), single-walled carbon nanotubes (SWCNTs), and multiwalledcarbon nanotubes (MWCNTs), as models to observe their distribution and oxidative damage in vivo.The results of Histopathological and ultrastructural examinations indicated that the liver and lungs were the mainaccumulation targets of these nanomaterials. SR-μ-XRF analysis revealed that SWCNTs and MWCNTs mightbe present in the brain. This shows that the three types of carbon-based nanomaterials could cross the gas–bloodbarrier and eventually reach the liver tissue. In addition, SWCNTs and MWCNTs could cross the blood–brainbarrier and accumulate in the cerebral cortex. The increase in ROS and MDA levels and the decrease in GSH,SOD, and CAT levels indicated that the three types of nanomaterials might cause oxidative stress in the liver.This suggests that direct instillation of these carbon-based nanomaterials into rats could induce ROS generation.In addition, iron (Fe) contaminants in these nanomaterials were a definite source of free radicals. However,these nanomaterials did not cause obvious damage to the rat brain tissue. The deposition of selenoprotein inthe rat brain was found to be related to oxidative stress and Fe deficiency. This information may support thedevelopment of secure and reasonable applications of the studied carbon-based nanomaterials.
分类： 核科学技术 >> 辐射物理与技术 提交时间： 2024-04-08
摘要： In the framework of the Lanzhou Quantum Molecular Dynamics (LQMD) model, a possible probe to the neutron-skin thickness (δnp) of neutron-rich 48Ca is studied in 140A MeV 48Ca + 9Be projectile fragmentation reaction based on parallel momentum distribution (p//) of residual fragments.The Fermi-type density distribution is employed to initiate the neutron density distributions in the LQMD simulation. A combined Gaussian function with different width parameters for the left side (ΓL) and the right side (ΓR) in distribution are used to describe the p// of residual fragments. The value of ΓL, taking neutron-rich sulfur isotopes as examples, shows a sensitive correlation to δnp of 48Ca, which is suggested to be a probe to determine the neutron-skin thickness of the projectile nucleus.
分类： 物理学 >> 核物理学 提交时间： 2024-03-09
Xin-Tong Du
Xiao-Bao Wei
Shao-Bo Ma
Li-Na Sheng
Xue-Heng Zhang
Shi-Tao Wang
Kai-Long Wang
Chun-Wang Ma
Hool-Jin Ong
Zhi-Yu Sun
Shu-Wen Tang
Yu-Hong Yu
摘要： The study of nuclide production and its properties in the N=126 neutron-rich region is the frontier and hot topic in nuclear physics and astrophysics research. The upcoming High energy FRagment Separator (HFRS) at the High Intensity heavy-ion Accelerator Facility (HIAF), an in-flight separator at relativistic energies, is characterized by high beam intensity, large ion-optical acceptance, high magnetic rigidity, and high momentum resolution power. It provides an opportunity for the study of the production and properties of neutron-rich nuclei around N=126. In this paper, an experimental scheme is proposed to produce the neutron-rich nuclei around N=126 and simultaneously measure their mass and lifetime based on the HFRS separator, and the feasibility of this scheme is evaluated by the simulations. The results show that under the high resolution optical mode many new neutron-rich nuclei approaching the r-process abundance peak around A=195 can be produced for the first time, and many nuclei with unknown mass and lifetime can be produced with high statistics. Using the time-of-flight corrected by the measured dispersive position and the energy loss information, the cocktails produced from the 208Pb fragmentation can be unambiguously identified. Moreover, the masses of some neutron-rich nuclei in the vicinity of N=126 can be measured with high precision using the time-of-flight magnetic rigidity technique. This indicates that the HIAF-HFRS facility has potential for the production and property research of neutron-rich nuclei around N=126, which is of great significance for expanding chart of nuclides, developing nuclear theories, and understanding the origin of heavy elements in the universe.
分类： 物理学 >> 核物理学 提交时间： 2023-11-14
Yijie Wang
Fenhai Guan
Dawei Si
Sheng Xiao
Boyuan Zhang
Yaopeng Zhang
Baiting Tian
Xianglun Wei
Herun Yang
Peng Ma
Rongjiang Hu
Limin Duan
Fangfang Duan
Qiang Hu
Junbing Ma
Shiwei Xu
Zhen Bai
Yanyun Yang
Jiansong Wang
Wenbo Liu
摘要： Two-body correlations of the isotope-resolved light and heavy clusters are measured in 86Kr+ 208Pb reactions at 25 MeV/u. The yield and kinetic variables of the A = 3 isobars, triton and 3He, are analyzed in coincidence with the heavy clusters of 7 A 14 emitted at the earlier chance. While the velocity spectra of both triton and 3He exhibit scaling behavior over the type of the heavy clusters, the yield ratios of t/ 3He correlate reversely to the neutron-to-proton ratio N/Z of the latter, showing the ping-pong modality of the N/Z of emitted clusters. The commonality that the N/Z of the residues keeps the initial system value is extended to the cluster emission in heavy ion reactions. The comparison of transport model calculations to the data is discussed.
分类： 物理学 >> 核物理学 分类： 物理学 >> 地球物理学、天文学和天体物理学 提交时间： 2023-09-12
Yang, Gaole
An, Zhendong
Jiang, Wei
Li,Xiankai
Qiu, Weiwei
Liao, Zhengfa
Zhuang, Ziyue
Zhang, Xiaoping
Chen,Shengli
Xiao, Erxi
Fang,Xiao
Li,XinXiang
Hu, Xinrong
Jiang, Bing
Wang, Jincheng
Ren, Jie
Luo, Wen
Zhu, ZhiChao
Lan, Haoyang
Cao, Zongwei
摘要： The neutron capture cross sections (${n, upgamma}$) of Bromine was performed with the time-of-flight (TOF) technique at the Back-n facility of the China Spallation Neutron Source (CSNS). Prompt $ upgamma$-rays originating from neutron-induced capture events were detected by four C${}_6$D${}_6$ detectors. The pulse height weighting technique (PHWT) and the double-bunch unfolding method based on the Bayesian theory were used in the data analysis. To obtain reliable measurement results, background deductions, normalization, and corrections were carefully considered. The multilevel R-matrix Bayesian code SAMMY was used to extract the resonance parameters in the resolved resonance region (RRR). The average cross sections in unresolved resonance region the was obtained from 10 to 400 keV. The experimental results were compared with the data of several evaluated libraries and previous experiments in the resolved and unresolved resonance region. The TALYS code was used to describe the average cross sections in the unresolved resonance region. Astrophysical Maxwell average cross sections (MACSs) of ${}^{79,81}$Br from $ kT $ = 5 to 100 keV was calculated over a sufficiently wide range of neutron energies. At a thermal energy of $kT=30$ keV, the MACS value for ${}^{79}$Br 638$ pm$64 mb is in good agreement with the KADoNiS recommended value. By contrast, the value of 293$ pm$29 mb for ${}^{81}$Br is substantially higher than those of the evaluated database and the KADoNiS recommended value.
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