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2020 Vol. 37, No. 1

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2020, 37(1): 1-2.
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Abstract:
Nuclear Energy and Nuclear Data
Calculation of Secondary Neutron Double Differential Cross Sections for Neutron Induced Reactions on Fe with GEANT4 and TALYS
Bingyan LIU, Zhiqiang CHEN, Rui HAN, Xin ZHANG, Guoyu TIAN, Fudong SHI, Hui SUN
2020, 37(1): 104-108. doi: 10.11804/NuclPhysRev.37.2019061
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The secondary neutron double differential cross sections of iron play an important role in the design, operation and maintenance of nuclear facilities. Reliable nuclear theoretical model and evaluation data are needed in calculation. The secondary neutron double differential cross sections of 8.17, 11.5, 14.1 and 18 MeV neutron induced on iron were calculated with GEANT4 code. The secondary neutron double differential cross sections of 25.7, 65, 100 and 150 MeV neutron induced on iron were calculated with TALYS and GEANT4 codes. Additionally, these calculation results were compared with experimental data. Research shows that, for the energy below 20 MeV, the ENDF/B-VIII.0 library is in good agreement with experimental data, and the BROND-3.1, CENDL-3.1, JENDL-4.0u and JEFF-3.3 libraries show some discrepancies with experimental data. For the energy between 20 and 150 MeV, the calculation results of the BERT model and the TALYS code are in good agreement with experimental data. The calculation results of BIC and INCLXX models are different from experimental data. On the whole, further research is needed for the neutron evaluated nuclear data and nuclear reaction model.
Study on Natural Circulation and Residual Heat Removal Capability of the Lead-based Fast Reactor
Ruonan YANG, Tianji PENG, Changping QIN, Xianwen LI, Wangsheng TIAN, Xukai FAN, Long GU
2020, 37(1): 109-118. doi: 10.11804/NuclPhysRev.37.2019052
Abstract(2008) HTML (800) PDF (4967KB)(75)
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The natural circulation characteristics is the key operating characteristic of the primary circuit of the lead-based reactor, which has an important influence on the passive residual heat removal system of the reactor. The natural circulation characteristics and residual heat removal capacity in the reactor are an important part of the thermal hydraulic research of reactor. Using the porous media method, the 1/4 3D calculation model of the CiADS lead-based reactor was established, and the steady state calculation of rated conditions and low power operating condition were performed by FLUENT code. In order to study the transient process of residual heat removal of CiADS lead-based reactor under the station blackout accident, a 2D equivalent model which according to the principles of thermal hydraulic equivalence was established for transient calculation. The results show that CiADS lead-based reactor has low power natural circulation operation capability and a certain degree of accident tolerance; The results of 2D equivalent model and 3D model agree well with each other and the 2D model can be used in transient analysis; The 2D transient calculation results show that the passive residual heat removal system can cope well with the station blackout accident, and the CiADS lead-based reactor has good passive safety performance.
Nuclear Physics
A Study of the Pion from the Basis Light-Front Quantization Approach
Hengfei ZHAO, Jiangshan LAN, Xingbo ZHAO
2020, 37(1): 1-10. doi: 10.11804/NuclPhysRev.37.2020016
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Abstract:

We study the properties of the pion through the light-front wave function (LFWF) obtained from the basis light-front quantization (BLFQ) approach. BLFQ is a nonperturbative approach to quantum field theory based on the Hamiltonian formalism. Our Hamiltonian contains the kinetic energy terms, a transverse confining potential motivated by holographic quantum chromodynamics (QCD), a complementary longitudinal confining potential, and the quark-gluon interactions based on QCD. Our basis space includes the lowest two Fock sectors, namely

and

. The obtained pion decay constant and electromagnetic radius (at the leading order Fock sector) are comparable to those from the particle data group (PDG). Next, we calculate the parton distribution function (PDF) of the pion based on the leading Fock sector LFWF. After QCD evolution, the resulting PDF is similar to the previous result (Lan et al., Phys Rev Lett, 2019, 122: 172001.), and agrees with the experimental data from the Fermi National Accelerator Laboratory (FNAL), as well as those from the European Organization for Nuclear Research (CERN).

Progress on the $ {\gamma} $ Spectroscopy in the A~80 Mass Region
Shouyu WANG, Wenzheng XU, Chen LIU, Zhiquan LI
2020, 37(1): 11-17. doi: 10.11804/NuclPhysRev.37.2020001
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In order to further explore important scientific issues such as spontaneous breaking of chiral symmetry in the A~80 mass region, the nuclear physics group of Shandong University at Weihai has studied excited states of nuclei in this region by in-beam gamma spectroscopy techniques. The level schemes of these nuclei were expanded. The symmetry, shape, and motion mode of these nuclei were systematically studied with respect to experiments and theories. According to experimental results, several chiral candidates including odd-odd and odd-A nuclei were found in the A~80 mass region, and chirality in the 80Br nuclei was confirmed by the lifetime measurements. In addition, the present work also discussed the evolution of chiral geometry and octupole correlations with increasing neutrons, and the systematic features of neutron-core excitations in near-spherical nuclei in the A~80 mass region.
A Proposal for Mass Measurements of Heavy Neutron-rich Ions at HIRFL-CSR
Mingzheng LIU, Meng WANG, Yuhu ZHANG, Chaoyi FU, Xu ZHOU, Min ZHANG, Yuanming XING, Mingze SUN
2020, 37(1): 18-25. doi: 10.11804/NuclPhysRev.37.2020009
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There are a large number of nuclides with unknown mass in heavy neutron-rich region, which urgently need to be measured. We propose to measure the mass of 204Pt and other heavy neutron-rich nuclides by using the isochronous mass spectrometry (IMS) at the research facility HIRFL-CSR. In the IMS experiments, the nuclides of interest are produced by using projectile fragmentation and stored in the storage ring CSRe. The revolution times of the stored ions are measured, from which the nuclear masses are extracted. To obtain high-precision results from the IMS experiments, it is required that several ions are stored in the Experimental Cooling Storage Ring(CSRe) simultaneously to correct for the effect of the magnetic-field instability. However, the production cross sections of the heavy neutron-rich nuclides are very small, so that the number of ions that can be stored in the CSRe is too low to fulfill the requirement. To solve this problem, it is proposed to use a production target with two different thicknesses at different areas. In this way, a sufficiently large number of ions can be produced and stored in the CSRe at the same time without reducing the yield of the target nucleus significantly. The simulations show that it is feasible to measure the masses of heavy neutron-rich nuclides at CSRe. The experimental settings are recommended.
Effect of Different Pairing Correlations on the Description of Nuclear Deformations within Energy Density Functional Framework
Haoqiang SHI, Xiaobao WANG, Guoxiang DONG, Hualei WANG
2020, 37(1): 26-33. doi: 10.11804/NuclPhysRev.37.2020006
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In this paper, using the Skyrme energy density functional theory, we have investigated the effect of different treatment of pairing correlations, \begin{document}$e.g.$\end{document}, Hartree-Fock-Bogoliubov (HFB), Hartree-Fock-Bogoliubov Lipkin-Nogami (HFBLN), and particle number projection on HFBLN, \begin{document}$etc.$\end{document}, on the potential energy surface (PES) calculations and ground-state energy. We also tested the effect of different pairing force, such as volume-pairing, surface-pairing, mixed-pairing force. We studied typical doubly-magic nuclei, such as 16O, 40Ca, 100Sn and 208Pb, which have spherical shape in their ground states. We studied the typical deformed nucleus 48Cr, and the binding energies of Cr and Fe isotopes. The PES of superheavy nucleus 298Fl is also studied. It is learned that the deformed minimum is not changed much by different pairing correlations. The pairing correlations bring about several MeV to the total binding energies. The correlation energy brought by HFBLN is more than that by HFB approximation, and that by projection method increases further. The softness of the deformed minimum is also changed by pairing correlations. The one by HFBLN is softer than the one by HFB. However, the deformed minimum become explicit by projection method. Pairing correlation can lower down the barrier in the PES. In the same approximation of the pairing correlation, PES results calculated by mixed-pairing and volume-pairing force are similar. It seems that in the PES calculations, the surface pairing force can bring more pairing correlations, thus the effect of surface pairing force is larger than that of volume- and mixed-pairing forces.
Dynamic Evolution of Excited Finite Nuclei under Mechanical Instability and Deterministic Chaos
Yongzhong XING, Yutian FANG, Xiaobin LIU, Yuming ZHENG
2020, 37(1): 34-39. doi: 10.11804/NuclPhysRev.37.2019053
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In the present paper the nonlinear characteristics of one-body dissipative of an excited finite nucleus has been studied by simulating the evolution of the nucleus 208Pb within the Quantum Molecular Dynamics (QMD) model . First, the phase diagram of the nucleus and the spinodal region were determined by computing the single particle energy and chemical potential. Then the position and momentum of each nucleons in the 208Pb were sampled according to uniform and fermi distribution respectively. After such preparation, taking these distributions as initial sates of QMD model, we simulated the evolution of the system in the action of the mean field with no collision term. The variation of the density and the fluctuation of the nucleons distribution have been analyzed. Our main attention paid on the comparison of the behavior of such quantities for the system started from 208Pb with different initial states. The sensitivity of the mean field dynamics on the initial space distribution of nucleons are demonstrated by calculating the Lyapunov exponents defined respectively in events space and phase space. The nonlinear dynamical mechanism of the one-body dissipation, and thus the multifragmentation of heavy-ion collisions at intermediate energy have been confirmed further. The conclusion is helpful for us both to understand the dynamical mechanism of the heavy-ion reactions and to extend our knowledge about the nonlinear dynamics.
Accelerator
EicC Collider Lattice Design
Ruiru WANG, Jiancheng YANG, Guodong SHEN, Geng WANG
2020, 37(1): 40-45. doi: 10.11804/NuclPhysRev.37.2019048
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Electron Ion Collider in China (EicC), a new plan proposed by Institute of Modern Physics, Chinese Academy of Science to upgrade the HIAF facility, is mainly designed for studying sea quark, gluon and valence quark. The Center Mass Energy of the EicC is near 20 GeV. In order to maintain polarizability of proton bunched beams, the pRing (proton Ring) is designed to have the octave shape layout, while the racetrack layout is adopted by the eRing (electron Ring) to make full use of the tunnel space. For pRing, the proton center energy is 20 GeV, the horizontal and vertical rms emittance is 300 and 180 nm·rad respectively, and the β function at collider point is 0.08 and 0.04 m in the horizontal and vertical plane. For eRing, the electron beam center energy is 3.5 GeV, the rms emittance in transversal plane is 60 nm·rad, and the β function at collider point is optimized to be 0.4 and 0.12 m in horizontal and vertical direction respectively. As a result, the designed luminosity can achieve 2×1033 cm–2s–1. Furthermore, the influence of chromaticity compensation scheme on the Dynamic Aperture (DA), including the compensation patterns, the beta function and the phase advance in the collision points, is also studied. Accordingly, chromaticity compensation scheme is finalized as compensating by arc and short straight sextupoles, the DA of the pRing (>8σ) and the eRing (>20σ) can meet the design requirement of the beam size larger than 6σ.
Prototype Verification of Non-PLL Phase Averaging Reference Line
Qi CHEN, Yuan HE, Xianwu WANG, Guirong HUANG, Zheng GAO, Zhenglong ZHU, Zongheng XUE, Kean JIN, Fanjian ZENG, Jinying MA
2020, 37(1): 46-52. doi: 10.11804/NuclPhysRev.37.2019051
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Radio frequency (RF) phase reference line is one of key components in particle accelerator, which can provide phase locked RF reference signal to low-level RF (LLRF) system, beam diagnostic system, timing system or other phase sensitive systems. To reduce phase fluctuations caused by ambient temperature changes in long-distance particle accelerators, phase reference system has been implemented in several accelerator plants. In current phase reference line (PRL) projects, thermal-control based and fibre phase-locked based are mainly implementation methods. Compared with these PRL solutions, the RF phase averaging method has been proven to be able to maintain phase stability between long-distance nodes and it is easier to be applied to installation and maintenance in situ. The method of using phase-locked loop (PLL) phase averaging PRL still has some limitation on nodes quantities. For considering of simplify structure and more nodes can be added and also decreasing requirements for devices, it is necessary to evaluate the phase averaging structure without PLL. The results for the single-end input and the dual-end input structure of non-PLL design show that both structures have the similar accuracy at 0.1° ~ 0.3°, and the results show that the possible reasons of phase instability in different implementation structures, besides ambient temperature, also has the material of coaxial cable, combination phase, imbalanced combination, etc.
Nuclear Technology
Development and Prospect of Shanghai Laser Compton Scattering Gamma Source
Hongwei WANG, Gongtao FAN, Longxiang LIU, Xiguang CAO, Wei LI, Yue ZHANG, Xinrong HU, Xinxiang LI, Junwen WANG, Tongsuo LU, Bosong HUANG, Zirui HAO, Pan KUANG, Yuhua HUANG
2020, 37(1): 53-63. doi: 10.11804/NuclPhysRev.37.2019043
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Laser Campton Scattering-LCS source is a new type X-ray or Gamma-ray light source based on the interaction of the relativistic electron beam with the laser photon. It has the characteristics of high energy, short wave length, fast pulse and high peak brightness, and has become one of the important options of advanced light source technology in the world. This paper introduces the production principle of laser Compton scattering light source, the historical development in China and international laboratory, and the laser Compton scattering light source facility currently running and under construction internationally. The Shanghai Laser Electron Gamma source(SLEGS) is under construction in Shanghai Light Source PHASE II project, the research on nuclear physics, nuclear astrophysics, nuclear waste disposal and nuclear medicine applications that can be carried out on this gamma source. With the upgrade of the Soft X-ray Free Electron Laser(SXFEL) to a user facility, and the Shanghai HIgh repetition rate XFEL aNd Extreme light facility(SHINE)- Large-scale scientific facility of the 13th Five-Year Plan will be completed in the future. The gamma energy of the Compton scattering source in LINear ACcelator (LINAC) will reach the GeV energy. Ultra-short pulse, high polarization, high-flux laser Compton scattering light source will usher in new development opportunities. The study of nuclear physics, astrophysics, particle physics and applied basic research based on Compton Gamma source will also reach a new level.
Nuclear Technology Application of the 4.5 MV Electrostatic Accelerator at Peking University
Yuan GAO, Xiangjun YANG, Jianyong WANG
2020, 37(1): 64-73. doi: 10.11804/NuclPhysRev.37.2019041
Abstract(2164) HTML (663) PDF (9772KB)(115)
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The 4.5 MV electrostatic accelerator of Peking University was designed and constructed independently by China in 1980 s. By this accelerator, in which some beam lines and terminals are installed, the isotope ions of hydrogen or helium can be produced in the energy range of 0.7~3.8 MeV, and continuous or pulsed quasi-monoenergetic neutron fields can be generated by ion beam bombarding target. This facility has provided an open experimental platform for domestic and oversea nuclear technology research groups for many years. In recent years, in order to meet the demand of material research in the fields of energy, aerospace and national defense in China, some upgrading works have been achieved. On the one hand, quasi-monoenergetic neutron fields (<7 MeV, 14~19 MeV) generated by this facility have applied to cross section measurement of (n, α) nuclear reaction and fusion neutron spectrometer calibration. On the other hand, the temperature controlling irradiation, nuclear reaction analysis and other experimental terminals have been installed to develop the function on nuclear materials irradiation damage, quantitative analysis of fusion materials, and so on. In addition, an in situ irradiation terminal for testing the electrical properties of semiconductor materials and an integrated ion beam analysis experimental terminal for studying the distribution of elements at the micro scale are designed. At present, the new terminals have been designed and assembled, and the installation and testing work are in process.
Design of a Digital Readout Module for SCA ASIC Testing
Sifan QIAN, Lei ZHAO, Han CHEN, Shubin LIU, Qi AN
2020, 37(1): 74-81. doi: 10.11804/NuclPhysRev.37.2019025
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Switched Capacitor Array (SCA) features high-speed sampling and low power consumption. High-speed waveform digitization based on SCA is an important research direction for high-precision time measurement. We are designing the SCA ASIC chips, of which several prototypes have been designed and the improvements are ongoing. In order to test and evaluate the future SCA ASIC chips, it is necessary to design a digital readout module with good compatibility. This paper presents the design of the readout module and the data readout software. The digital readout module integrates the functionality of the control, configuration and data readout of the ASIC under test within one FPGA device. A DDR3 chip is used for data caching, and a USB3.0 interface is designed for data transmission. The readout software is designed based on Python3.7 and contains the functions such as data acquisition and waveform drawing. This module was successfully used in the initial testing of the second version of the SCA prototype ASIC, and the test results indicate that the readout module works as expected.
Cross Discipline
Study on the Solid-liquid Interface Using Ion Beam Analysis in Vacuum
Xiaoyue LI, Tao YU, Guangbo MAO, Jinlong GUO, Yaning LI, Hailei ZHANG, Ruqun WU, Wenjing LIU, Jing ZHAO, Cheng SHEN, Hao SHEN, Guanghua DU
2020, 37(1): 82-87. doi: 10.11804/NuclPhysRev.37.2019031
Abstract(1304) HTML (430) PDF (3292KB)(43)
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The in-situ and real-time high-precision measurement of the composition and dynamic change of elements or ions (charges) at the solid-liquid interface with nano-to-micron thickness is very important in the understanding of the interface interaction and reaction, while traditional high-resolution ion beam analysis can not directly measure liquid samples in vacuum environment. In this paper, a solid-liquid interface probe in vacuum was developed. The probe used Si3N4-Al nanocomposite membrane as vacuum sealing window and electrochemical electrode. The Rutherford Backscattering Spectroscopy (RBS) analysis and particle-induced X-ray Emission (PIXE) analysis with the solid-liquid interface probes of 0.01 mol/L BaCl2 and 1 mol/L LaCl3 solution were successfully carried out using Fudan University nuclear microprobe. The experimental results show that the nano-window of solid-liquid interface probe can withstand the irradiation of 2 MeV He+ ions with a dose of 1.0×1018 ions/cm2 in vacuum. The distribution of structure elements in solid-liquid interface probes was successfully obtained by PIXE analysis. The concentration of La and Cl in micron deep solution of electrode interface was obtained by Rutherford backscattering analysis with 20-nm-resolution. On the surface of 1 mol/L LaCl3 solid-liquid interface electrode, electrolyte ions accumulated at a high concentration at negative voltage (–2.3 V), while electrolyte ions distributed at a low concentration at positive voltage (+2.3 V), and electrolyte solutions tended to bulk concentration at a depth of about 1 250 nm.
Dose Variation Analysis and Position Correction Method for Carbon-ion Pencil Beams under Uniform Magnetic Fields
Qianqian MENG, Xiaofang ZHANG, Xinguo LIU, Zhongying DAI, Qiang LI, Weiqiang CHEN
2020, 37(1): 88-96. doi: 10.11804/NuclPhysRev.37.2019038
Abstract(2006) HTML (428) PDF (7276KB)(38)
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The influence of uniform magnetic fields on the dose distribution of carbon-ion pencil beams is analyzed, and the influencing effect is corrected to provide guidance for the clinical application of MRI-guided carbon ion radiotherapy. In this study, the Monte Carlo method was used to simulate the dose distribution of carbon-ion pencil beams with different energies under different magnetic fields. We found that the transverse uniform magnetic fields had little effect on the range shortening of the carbon-ion pencil beams, but had obvious impact on the lateral shift, especially at the Bragg peak of the carbon-ion beams. The lateral shift was related to the carbon-ion beam energy and magnetic field strength. According to the simulation results, we obtained an equation for calculating the lateral shift of carbon-ion beams under the magnetic fields, and proposed an angle correction method to reposition the Bragg peak of carbon-ion beams. These results will be used to MRI-guided carbon ion radiotherapy in the future.
Preliminary Research on the Radiation Sensitizing Effect of Ganoderic acid A on Human Hepatoma Cells
Changsheng SHAO, Qunxia ZHANG, Jianye WANG, Qing HUANG
2020, 37(1): 97-103. doi: 10.11804/NuclPhysRev.37.2019055
Abstract(2773) HTML (479) PDF (3352KB)(26)
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The aim of this study was to investigate the effect of ganoderic acid A (GAA) on the radiosensitivity of human hepatoma cell line HepG2 for high-LET neutron and low-LET gamma-ray radiations. In this research, the CCK-8 method was used to detect the inhibition of proliferation of HepG2 cells treated by GAA. It was found that 5 μmol/L GAA treatment had weak proliferation inhibition effect on HepG2 cells, and so this concentration of GAA was applied to the cells for 24 h in the subsequent experiments. CCK8 assay, clone formation assay, apoptosis assay, and the foci formation of \begin{document}$\gamma $\end{document}H2AX were detected after irradiated by different doses of either neutron or \begin{document}$\gamma $\end{document}-ray. The experiments showed that the high-LET neutron irradiation had a higher proportion of apoptosis than the low-LET γ ray irradiation for the cells without GAA treatment, while for the cells with GAA treatment, the proportion of apoptosis also decreased significantly for the cells under \begin{document}$\gamma $\end{document}-ray irradiation. After treated with GAA, the proportion of induced apoptosis was significantly increased compared to the control group without GAA treatment. Besides, after GAA treatment, the cell proliferation inhibition rate also increased with the increase of irradiation dose. Therefore, these results suggest that GAA can increase the radiosensitivity of HepG2 cells, and HepG2 cells are more sensitive to the high-LET neutron irradiation than low-LET \begin{document}$\gamma $\end{document}-ray irradiation. As such, this study suggests that GAA not only may serve as a natural radiosensitizer, but also may provide a new radio-therapy method which may be suitable for cancers, or particularly, liver cancers.