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Preliminary Study on Male Individual Radiosensitivity by Cytochalasin-B Blocked Micronucleus Assay
Changhao XIAO, Ping WANG, Junchao FENG, Lijun ZHENG, Hao HUANG, Shuxian PAN, Jianing XU, Shuhong JIN, Bingyan LI, Guangming ZHOU, Jing NIE
 doi: 10.11804/NuclPhysRev.38.2021036
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Methods and criteria for the identification of male individual radiosensitivity are investigated. The peripheral blood of 50 male volunteers was irradiated with different doses of X-ray, the micronucleus frequency rate (MNF) was measured by cytokinesis-block micronucleus assay, and the central standard curve of micronucleus dose effect was drawn by second-order multinomial fitting method so that the individual dose-response curve of micronucleus was compared with the standard curve to judge individual radiosensitivity. In the dose range of 0.0~2.5 Gy, the central equation of second-order polynomial fit for dose effect is (MNF=0.014 7+0.036 2D+0.023 1D2, R=0.726). Among the 50 male volunteers, 13 were sensitive to radiation (26.0%) and 14 were resistant (28.0%), which basically fits the normal distribution. Spearman rank correlation analysis showed that the MNF increased with the dose and there was a positive correlation between the background MNF and the radiosensitivity of each dose, but negative correlation with the radioresistance. In conclusion, a "curve-instead-of-dose" male individual radiosensitivity identification method was established. Moreover, it was found that the background of micronuclei in peripheral blood lymphocytes was positively correlated with individual radiosensitivity.
Research on Closed Loop Control Technology of Magnetic Field Based on PID Algorithm
Baojia WANG, Yuhui GUO, Wentian FENG, WANG Rui, Guangquan CHEN
 doi: 10.11804/NuclPhysRev.38.2021002
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Most of the existing methods for beam control using magnet field use the open-loop mode, which is to directly set the value of current and voltage of the magnet power supply output based on the demand of magnetic field intensity. However, magnetic fields in the open-loop state are easy to be deflected due to the field noise and the eddy current effect of the magnet. To solve this problem, the closed-loop control system of the magnetic field based on the PID algorithm is developed in this article. This system takes the deflection magnet as the control object, uses the Hall sensor to obtain the magnetic field intensity as the feedback, and utilizes the output of the excitation current of the magnet power supply as the input of the control system. The controller uses the PID algorithm to automatically tune the output of the magnet power supply to achieve the closed-loop control of the magnetic field. The result shows that when the PID parameters are properly set, the magnetic field offset can be significantly reduced by the closed-loop control method which takes the online measured value of the magnetic field as the feedback signal to simultaneously tune the excitation current value of the magnet power supply.
Design of Data Acquisition System for TOF Detectors in the CEE Experiment
Ruolin LIU, Junfeng YANG, Tianxing WANG, Hongwei ZHAO, Lei ZHANG
 doi: 10.11804/NuclPhysRev.38.2020070
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The CSR External-target Experiment(CEE) system under development may reach an average data rate of 2 GB/s after being triggered. In response to the design requirements of the entire spectrometer, a generic stream processing data acquisition architecture D-Matrix is put forward in the article, and a specific scheme of D-Matrix in the Time-of-Flight detector(TOF) subsystem is proposed. The DAQ of the TOF system uses high-speed serial communication methods such as optical fiber and PCIe bus to complete data transmission from Front-End Electronics(FEE) to the servers, and deploys and cascades stream processing nodes with a unified interface to complete event building, command routing, Real-time status monitoring and displaying and data storage tasks. In addition, the DAQ of the TOF system has strong versatility in hardware and logic design, it also can be compatible with other sub-detector systems, and can be further applied to the global system of CEE experiments.
Study on Production Mechanism of the Neutron-rich Nuclei in Multinucleon Transfer Reactions via Reaction Time Analysis
Cheng LI, Jiawei GAO, Jingwen ZHANG, Kaiwen ZHAO, Junlong TIAN
 doi: 10.11804/NuclPhysRev.38.2020045
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The multinucleon transfer reaction processes of $^{136}{\rm{Xe}}$+$^{198}{\rm{Pt}}$ are investigated by using the ImQMD model. The TKE-Mass distributions of binary fragments at different contact time scales are analysed. It is found that the quasielastic collisions, the deep-inelastic collisions and the quasifission reactions can be roughly distinguished by the contact time. By analysing the double differential cross sections of the TLFs and the isotopic cross sections of Ba nuclei under the different contact time, we find that the neutron-rich nuclei are produced in the deep-inelastic collisions. In addition, the TLFs with emission angle around 0° are produced in central collisions for the reactions of $^{136}{\rm{Xe}}$+$^{198}{\rm{Pt}}$.
Study of Proton Induced Reactions on Molybdenum Using TALYS and EMPIRE
Hui SUN, Zhiqiang CHEN, Rui HAN, Bingyan LIU, Xin ZHANG, Guoyu TIAN, Fudong SHI
 doi: 10.11804/NuclPhysRev.38.2021004
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Direct production of 99Mo and 99mTc with accelerator has a good development prospect in the field of nuclear medicine. Accurate and reliable nuclear reaction data is of great significance for isotope production. In this paper, the cross sections for natMo(p, x)96m+gTc, 100Mo(p, x)99Mo and 100Mo(p, 2n)99mTc reactions being taken from EXFOR database have been analyzed, and the experimental data were fitted by polynomial fit method. The excitation functions of natMo(p, x)96m+gTc、100Mo(p, x)99Mo and 100Mo(p, 2n)99mTc reactions were calculated up to 40 MeV by using TALYS-1.95 and EMPIRE-3.2.3 code with different energy level density and pre-equilibrium emission models. For the natMo(p, x)96m+gTc reaction, the calculation results predicted by preeqmode 1, 2 models are in good agreement with the experimental data when the input parameter ldmodel 6 of level density is used in TALYS-1.95 code. For the 100Mo(p, x)99Mo reaction, the calculation results predicted by preeqmode 4 models are in good agreement with the experimental data when the input parameter ldmodel 6 of level density is used in TALYS-1.95 code. For the 100Mo(p, 2n)99mTc reaction, the calculated results predicted by LEVDEN 2 in EMPIRE-3.2.3 code are in good agreement with the experimental data.
Design and Implement of HIRFL Radiation Safety Interlock System
Weiwei YAN, Youwu SU, Bo YANG, Yao YANG, Wuyuan LI, Zongqiang LI, Wang MAO, Yang LI, Lijun WANG, Fuhong MA
 doi: 10.11804/NuclPhysRev.38.2020060
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The Heavy Ion Research Facility in Lanzhou(HIRFL) is the largest heavy ion research facility in China, which has the most kinds of accelerated ions and the highest energy. Radiation will be generated in the accelerator tunnel during the operation of HIRFL, so it is necessary to establish a radiation safety interlock system to ensure the radiation safety of the workers. The system folows the design principles of zone partition interlocking, reliable hardware, failure protection, redundancy and independence, self-locking, etc. Redundant PLCs with high reliability are used as the central controller and interlocking components with high safety are selected. The successful establishment of the radiation safety interlock system is of great significance to the radiation safety of the staff at HIRFL, and it can also provide a reference for the design of interlock systems of other accelerators.
Overview of Atmospheric Tracing by Using Cosmogenic Nuclides of 10Be, 7Be, 22Na
Kejun DONG
 doi: 10.11804/NuclPhysRev.38.2020073
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The atmospheric cosmogenic nuclides of 10Be, 7Be, 22Na are of great significance to research on global climate change and atmospheric environmental governance, as the sensitivity tracer of the Stratosphere-Troposphere Exchange (STE) dynamic processes. The current status of the international research on the application of these nuclides in STE and the difficulties are introduced. The advantages and research basis of Accelerator Mass Spectrometry(AMS) in this respect are summarized. Feasibility analysis and exploration of the key technologies faced by AMS measurement of 7Be and 22Na are presented based on the compact low energy AMS system and the established 10Be measurement method of Tianjin University.
The Effect of Cold Rolling and Annealing on the Microstructure and Irradiation Hardening Resistance of V-5Cr-5Ti Alloys
Mengke NIU, Yitao YANG, Chonghong ZHNAG, Xuxiao HAN, Zengde LI
 doi: 10.11804/NuclPhysRev.38.2021006
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Vanadium alloys (V-5Cr-5Ti) have been considered as the candidate materials for the first wall and the blanket of fusion reactors. Different fabrication process will affect the performance of vanadium alloy in fusion reactors. In this study, the response of hardening of V-5Cr-5Ti vanadium alloys with different cold deformation (40%, 60% and 80%) followed by annealing treatment (1 273 K for 1 h) under irradiation with 337 MeV Fe ions was investigated. The irradiation experiment was performed at a terminal of the Sector-Focused Cyclotron(SFC) at HIRFL(Heavy Ion Research Facility in Lanzhou). The results of electron backscattering diffraction(EBSD) indicated that the proportion of fine broken grains in the sample increased and the average grain size decreased with the increase of cold deformation amount. After annealing, the distribution of grains become more uniform with the fine broken grains growing up and the large grains almost disappeared. The results of the Vickers hardness test show that the hardness increases with the increase of cold deformation amount and decreases after annealing treatment. After irradiation, the hardness of all samples increased significantly, which suggested the occurrence of irradiation hardening. In both cold rolling samples and annealing samples, the irradiation hardening effect decreased with the increase of cold deformation amount, which indicated that cold rolling can significantly improve the irradiation hardening resistance property. Based on the EBSD and hardness results, the mechanism of the effect of cold rolling and annealing on irradiation hardening resistance property of V-5Cr-5Ti was discussed. The increase of the cold deformation amount results in the increase of the sink strength, which suppressed the occurrence of irradiation hardening. The annealing treatment results in the decrease of the density of grain boundary and dislocation and the decrease of the total sink strength, which caused more significant irradiation hardening in the sample with annealing treatment.
Radionuclides Study of Lead-bismuth Eutectic Spallation Target in CiADS
Shiyu SONG, Junkui XU, Yonggang YAN, Yuxuan HUANG, Zhiweng WEN, Jianling RAN, Jinhuang YAN, Yiwei GONG, Dapeng LI, Sicheng WANG, Peng LUO
 doi: 10.11804/NuclPhysRev.38.2021009
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Lead-bismuth eutectic(LBE) is the candidate material of spallation target for China initiative Accelerator Driven System(CiADS). Long-term irradiation makes the LBE highly radioactive. Most of the spallation target radionuclide studies focused on the effects of the proton beam and ignored fission neutrons from the reactor. In this paper, both the fission neutrons and the high-energy protons have been taken into account in the radionuclide calculations of LBE and spallation target structural parts by coupling codes FLUKA and MCNP. Contributions from the fission neutron and the high-energy proton have been compared in the aspects of the activity, main radionuclides, toxicity, and the decay photon of radioactive products. The main shell, guide tube, and beam tube are significantly affected by the fission neutron activation. When the reactor tends to be critical, the fission neutron-induced LBE target activations are even greater than that induced by the proton beam. In the LBE itself, 96.66% of 210Po is induced by the fission neutrons. These results illustrate that fission neutrons are also essential for the radionuclides calculation of LBE and its structural parts. In addition, this study provides reference data for the radiation protection of CiADS and a more accurate method for the radionuclides study of the spallation target in ADS systems.
2021, (2): 1-2.  
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Nuclear Physics
β-delayed γ Decay of the Nucleus 28S Near the Proton Drip-line
Qirui GAO, Xinxing XU, Xiaohong ZHOU, Lijie SUN, Pengfei LIANG, Jiajian LIU, Chengjian LIN, Lee Jenny, Zhihuan LI, Hongyi WU, Yanyun YANG, Jiansong WANG, Dongxi WANG, Yihua LAN, Peng MA, Fangfang DUAN, Zhihao GAO, Qiang HU, Zhen BAI, Junbing MA, Jianguo WANG, Fupeng ZHONG, Chenguang WU, Diwen LUO, Yin JIANG, Yang LIU, Dongsheng HOU, Ren LI, Nanru MA, Weihu MA, Guozhu SHI, Gongming YU, Dipika Patel, Shuya JIN, Yufeng WANG, Yuechao YU, Qingwu ZHOU, Peng WANG, Liyuan HU, Xiang WANG, Hongliang ZANG, Pengjie LI, Haofan ZHU, Zheyang LIN, Qingqing ZHAO, Lei YANG, Peiwei WEN, Feng YANG, Huiming JIA, Gaolong ZHANG, Min PAN, Xiaoyu WANG, Haohan SUN, Zhengguo HU, Ruofu CHEN, Minliang LIU, Weiqing YANG
2021, 38(2): 117-122.   doi: 10.11804/NuclPhysRev.38.2020084
Abstract(134) HTML(23) PDF (6286KB)(31)
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The nucleus 28S (isospin projection $ T_{Z}=-2 $) near the proton drip-line was produced, separated and purified by HIRFL-RIBLL1 facility and the measurement of $\beta$-delayed $\gamma$ decay of 28S was performed using a detector array consisted of double-sided silicon detectors and Clover-type high purity germanium detectors. Five $\gamma$ transitions from $\beta$ decay of 28S were precisely measured and the corresponding energies of the states of daughter 28P were obtained. The branch ratios of low-lying states of 28P populated by $\beta$ decay were extracted for the first time and the new partial 28S $\beta$-decay scheme was deduced. This work provides accurate data for the further study of mirror asymmetry in 28S/28Mg.
Correlation Between Neutron Star Observation and Equation of State of Nuclear Matter at Different Densities
Jing ZHANG, Dehua WEN
2021, 38(2): 123-128.   doi: 10.11804/NuclPhysRev.38.2021019
Abstract(86) HTML(27) PDF (3153KB)(14)
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Neutron star matter is mainly composed of asymmetric dense nuclear matter. At present, there is still great uncertainty in the understanding of the high-density asymmetric nuclear matter through the terrestrial experiments, such as the heavy ion collisions. With the improvement of astronomical observation accuracy and the increase of observable measurements of neutron stars, it is possible to reverse constraint the state of high-density nuclear matter based on astronomical observation of neutron stars. Theoretically investigating the correlation between the observable measurements of neutron stars and the equation of states (EOSs) at different density sections will be helpful to the research of the reverse constraints. In this work, by employing the piecewise polytrope EOSs, the observable measurements of the radius(R), tidal deformability($\varLambda$), moment of inertia(I) of the neutron star $etc$. are calculated and analyzed, and the correlations between these observations and each density segment of the EOSs are given. The results show that tidal deformability ($\varLambda$) and f-mode frequency ($\nu$) of a canonical neutron star ($M \!=\! 1.4\, M_{\odot}$) are mainly correlated with $0.5\rho_{\rm{sat}} \!\sim\! 1.5\rho_{ sat}$, $2.5\rho_{\rm{sat}} \!\sim\! 3.5\rho_{\rm{sat}}$ and $3.5\rho_{\rm{sat}} \!\sim\! 4.5\rho_{\rm{sat}}$ segments of EOSs; the neutron star radius (R) are mainly correlated with $1.5\rho_{\rm{sat}} \!\sim\! 3.5\rho_{\rm{sat}}$ and the crust segments of EOSs; the moment of inertia (I) are mainly correlated with the density below $ 4.5\rho_{\rm{sat}}$ segments of EOSs.
Generate Configurations for Lattice QCD Study
Zhe LI, Liuming LIU
2021, 38(2): 129-135.   doi: 10.11804/NuclPhysRev.38.2021022
Abstract(83) HTML(22) PDF (4993KB)(10)
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Configurations are the basis of lattice QCD calculations. In this paper, we generate a set of configurations with the Wilson clover quark action using the open source software Chroma. The parameters are tuned such that the lattice spacing is ~0.105 fm, pion mass is ~220 MeV. The volume is $32^3 \times 64$. These configurations will be used to study nucleon structure and exotic hadronic states in lattice QCD.
Lattice QCD Calculation of the Form Factor by Interpolation within Finite Volume
Wenhao ZHANG
2021, 38(2): 136-146.   doi: 10.11804/NuclPhysRev.38.2021010
Abstract(58) HTML(15) PDF (3775KB)(2)
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This paper discusses the finite-volume effect in calculating hadron form factors using lattice QCD framework. Taking Pion as the example, we introduce the method of extracting hadron form factors from three-point correlation functions computed in lattice QCD, but only at separated points in the momentum space because of the finite-volume effect. This paper gives one interpolation algorithm which respects rotation symmetry and also provides a sketch of another interpolation method which applies the continuous Fourier transform, both methods continuously giving form factor results on the momentum space based on the discrete values. These algorithms are examined under numerical models and realistic lattice systems. The results given by the interpolation are independent of specific systems and can be easily generalized to a variety of lattice systems. Our conclusion also provides valuable information which could help determining the proper size of lattice systems.
Accelerator
Simulation Study about the Effects of Different Film Materials on α Beam Properties
Wei CHEN, Xinmiao WAN, Zhihui LI
2021, 38(2): 147-152.   doi: 10.11804/NuclPhysRev.38.2021001
Abstract(59) HTML(18) PDF (3361KB)(15)
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The beam energy extracted from cyclotron is fixed, it is necessary to adjust it to meet different demands of different experiments. This study focuses on the feasibility of using thin film materials to change the beam energy. The ranges of 30 MeV α beams (extracted from cyclotron) in materials include diamond, aluminum and copper are calculated by the SRIM program, and the relationship between material thickness and the required beam energy is determined. The horizontal and vertical emittances of α beams, after being reduced to 9 MeV by interacting with different materials, are calculated by G4Beamline program. The following results are obtained: After penetrating the thin film materials, the size of beam spot approximately remained the same. The growth of beam transverse emittances is mainly caused by the increase of the divergence angles, among which the diamond film causes the least increase of beam emittance, and the root mean square value of the divergence angle is about 16 mrad. There is no significant dependency on the value of initial beam divergence angle (the root mean square value of initial divergence angle is less than 1 mrad). Vertical energy spread caused by different materials is about 1 MeV (FWHM) that is only determined by the final beam energy and has no connection with the kind of material. The more energy has lost, the greater the energy spread would be. Besides, the 30 MeV initial α beams interacting with thin film materials (diamond, copper, aluminum etc.) could produce about 109/μA neutrons and γ particles, so radiation protection must be considered in practical applications.
Design of Controller for Extraction BUMP Power Supplies in Medical Heavy-ion Facility
Shuning LÜ, Jiang ZHAO, Zhongzu ZHOU, Daqing GAO
2021, 38(2): 153-158.   doi: 10.11804/NuclPhysRev.38.2020080
Abstract(58) HTML(35) PDF (3216KB)(9)
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The BUMP power supply is the key equipment responsible for the beam extraction of the medical heavy ion accelerator. The synchronization of the current rise affects the extraction efficiency of the beam, and the diversity of the current waveform is closely related to the treatment mode and treatment accuracy. It is necessary to generate 1~5 ms rising and accurately synchronized excitation current on the convex rail magnet (0.2~0.4 mH), and ensure the current tracking and the diversity of the waveform. Real-time adjustment of the strong excitation voltage and current waveform based on characteristic parameters are adopted. Control Method. This article introduces the software and hardware design of the digital controller for the BUMP power supply based on Inter's SoC(System-on-a-Chip) technology, and it is applied to the medical heavy ion accelerator device for the first time. After field verification, it is produced on different convex rail magnets. The synchronously changing current of 1~5 ms is achieved, and the tracking accuracy (>5 s) of the current rising period is guaranteed, which meets the design requirements.
Design of Non-single Operation Mode Dipole Magnet Power Supply Controller for Medical Accelerator
Yuzhen HUANG, Yuhang LI, Yuxi YAO, Daqing GAO, Huajian ZHANG, Yulian TAN
2021, 38(2): 159-165.   doi: 10.11804/NuclPhysRev.38.2020074
Abstract(37) HTML(7) PDF (6573KB)(3)
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In recent years, ion therapy technology has developed rapidly in China and abroad. To meet the demands of the accelerator commissioning and the energy requirements of the different treatment scheme for the accelerator facility, the power supplies of the dipole magnets in the energy selection and beam transport system are required to work in the modes of DC, in-order trigger and periodic pulse. Using the integrated box controller independently developed by the Institute of Modern Physics, Chinese Academy of Sciences, the control and protection function of the power supply are realized. In order to meet the requirements of commissioning and treatment working modes, the controller has been designed to support the local and remote control network protocols, between which the switch can be achieved through the button on the touch screen. The power supply specifications has been tested after the main circuit and controller were designed and assembled. The test results indicate that the power supply can work well under the different modes, the long-term stability of current rating reached 21 ppm, and the current ripple was less than 0.000 4, exceeding the design index.
Research on Ripple Suppression of Magnet Power Supply Based on CSAPF
Yongqiang WANG, Xinhua YANG, Jiqiang LI, Yuzheng HUANG, Daqing GAO, Wei LUO
2021, 38(2): 166-174.   doi: 10.11804/NuclPhysRev.38.2020064
Abstract(50) HTML(17) PDF (4430KB)(3)
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Due to the existence of a large number of nonlinear devices in the accelerator system, a large number of ripples are generated, which seriously affects the control of the accelerator magnetic field on the particle trajectory. In order to realize the suppression of accelerator DC power supply ripple, related researches mainly focused on using voltage-type active power filter to reduce DC power supply ripple, but this method has problems such as insufficient suppression accuracy, response delay, and large switchgear loss. In view of the above problems, this paper compares the main circuit topology of current-type and voltage-type active power filters, investigates the pulse width modulation technology and control strategies of current-type and voltage-type active power filters, and analyzes the performance of different active power filters in the accelerator system to suppress the output current ripple of magnet power supply. Through simulation analysis and experimental verification, it is found that the current-type active power filter has a significant suppression effect on the output current ripple of the magnet power supply, and the current-type active power filter can directly control the output ripple current, and the ripple accuracy is suppressed more highly. With the CSAPF put into use, the load current ripple is significantly reduced, and the current ripple coefficient reaches 1.6×10–5.
Nuclear Technology
Study of Low Temperature Radon Removal Technology and Low Background Radon Measurement in Nitrogen
Guangpeng AN
2021, 38(2): 175-181.   doi: 10.11804/NuclPhysRev.38.2020063
Abstract(84) HTML(15) PDF (3838KB)(7)
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High-purity and low-background nitrogen plays an important role in the low-background experiments, and it is necessary to study radioactive impurities removal technology and low-background radon measurement in nitrogen. The research uses low-temperature adsorption technology to remove radioactive impurities in nitrogen. At the same time, electrostatic collection and low-temperature enrichment methods are combined to measure ~10 μBq/m3 radon in nitrogen. The result shows that the purification system can reduce the radon background in nitrogen by 20 mBq/m3 to (25.2±5) μBq/m3, namely, can reduce the radon background by 800 times. It is also found that the purification capacity is related to the radon background in nitrogen. In the range of radon background from dozens of mBq/m3 to dozens of μBq/m3, the purification capacity decreases with the lower radon background. The main reason is that the adsorption capacity decreases with the lower partial pressure of radon. In addition, the influence of radon pollution caused by system background and leakage increases significantly under very low background.
The Accuracy Fan-out of T0 for Back-n White Neutron Facility at CSNS
Xuyang JI, Ping CAO, Tao YU, Likun XIE, Xinyi TANG, Zhijie JIANG, Jiawen LI, Qi AN
2021, 38(2): 182-189.   doi: 10.11804/NuclPhysRev.38.2020062
Abstract(73) HTML(19) PDF (8245KB)(7)
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The Back-n White Neutron Source is located in China Spallation Neutron Source(CSNS). It aims to measure nuclear data under different neutron energies. The neutron’s energy is obtained by the Time Of Flight(TOF) of neutron. In experiment, the time when proton bunches hit the thick tungsten target is considered as the start point of TOF(T0), and the corresponding electronic signal is used to trigger the whole electronic system. The accuracy fan-out of T0 signal will have a significant influence on the accuracy of the TOF measurement and the synchronization of each channel of electronic system. A two-stage accuracy fan-out method of back-n T0 signal is proposed. The T0 signal from CSNS proton accelerator is fanned out by T0 fan-out module to two underground experiment station through long cable. The fan-out module uses signal pre-emphasis technology to improve the signal transmission quality of T0 signal through more than 100 m long cable and guarantee that the T0 signal has a very fast signal leading edge, so as to ensure the accuracy of time timing. The electronic system takes the advantage of the high-performance backplane resources of the chassis by PXIe, so as to realize the global precision and synchronous fan-out of T0 signal. The experimental results show that the leading edge jitter of the T0 signal distributed by the fan-out module reaches 25 ps, the multi-channel accuracy of the chassis reaches 45 ps, and the measurement accuracy of the TOF can reach 248 ps, which meets the requirements of the measurement accuracy of the neutron time of flight of the white light neutron source.
Monte Carlo Simulation Study on Optimization of Detection Efficiency and Spatial Resolution of Coated nMCP
Lianjun ZHANG, Jianrong ZHOU, Jianqing YANG, Jinhao TAN, Yushou SONG, Zhijia SUN
2021, 38(2): 190-195.   doi: 10.11804/NuclPhysRev.38.2020058
Abstract(55) HTML(17) PDF (10365KB)(5)
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Since neutron sensitive microchannel plates (nMCP) has high detection efficiency and the spatial resolution, combined with advanced readout electronics it can be a better choice for energy-resolved neutron imaging detectors. Compared with the matrix-doped nMCP, the nMCP based on Atomic Layer Deposition(ALD) has the advantages of less neutron sensitive material consumption and high secondary electron emission coefficient on the inner wall of the channel. Firstly, the typical neutron and gamma signal of natGd-doped nMCP were studied experimentally. Geant4 simulation and theoretical calculation were performed to optimize the pore diameter, wall thickness, bias angle and coating thickness of the coated 10B2O3 nMCP. It was shown that the thermal neutron detection efficiency was about 56% and the spatial resolution was about 22 μm when the coating thickness was 1 μm, the pore diameter was 10 μm, the wall thickness was 1 μm and the bias angle was 3°. The results are of great significance to the geometric parameter design of nMCP used as energy-resolved neutron imaging detectors at CSNS.
Study on the Influence of Different Neutron Source on the Active-well Neutron Coincidence Method by MCNPX
Fengfei LIU, Jiaying LU, Huabin WU, Zhen YU
2021, 38(2): 196-202.   doi: 10.11804/NuclPhysRev.38.2021003
Abstract(351) HTML(23) PDF (3746KB)(13)
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The model of Active-Well Coincidence Counter(AWCC) was established by MCNPX, meanwhile, with two types of induced neutron source (Am-Li and Am-Be), the neutron coincidence count rate of low enriched uranium was simulated, and the comparison of the measurement accuracy between the two simulations was also demonstrated. It was found that the coincidence count rate induced by Am-Be source was lower than that induced by Am-Li source, and the fitting degree of scaled mass curve under Am-Be source was better than that under Am-Li source, the corresponding relative error was also lower than that of under Am-Li source. The relative error range of uranium mass corresponding to the inspection point under Am-Li source is 0.3%~13%. The relative error range under Am-Be source is 0.1%~4.5%. According to the results, for the measurement of the mass of low enriched uranium by AWCC, it could be better to choose Am-Be source for reducing measurement relative error.
Cross Discipline
The Effect of Initial Microstructure of the Oxides on Irradiation Hardening/Embrittlement Behavior of 16Cr-ODS Steel
Yuguang CHEN, Chonghong ZHANG, Zhaonan DING, Yitao YANG, Yin SONG
2021, 38(2): 203-209.   doi: 10.11804/NuclPhysRev.38.2020052
Abstract(62) HTML(22) PDF (8583KB)(9)
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The irradiation hardening and embrittlement behavior of three kinds of Oxide Dispersion Strengthened(ODS) steel (MA956, 16Cr-4Al, 16Cr-0.1Ti) are investigated by using the HIRFL(Heavy Ion Research Facility in Lanzhou). The main motivation is to find the relation between diameter and density of the oxides and irradiation hardening/embrittlement behavior of different ODS steels. These three kind of materials are irradiated by Ne and Ni ions, and get a uniform damage layer by using the energy degrader. The Nano-hardness and elongation of the materials are obtained by Nano-indentation and small punch test. The sink strength was calculated with the mean diameter and density of the materials. Then followed by nano-indentation test and small punch test to get the irradiation hardening and ductility loss. Results show that irradiation resistance of the materials rise with sink strength(S) increasing.
Classical Electron Capture in Collisions of Ions with H, He Atoms at Low and Intermediate Velocities
Tao GUO, Xinfei HUI, Baowei DING
2021, 38(2): 210-214.   doi: 10.11804/NuclPhysRev.38.2021007
Abstract(40) HTML(21) PDF (2906KB)(14)
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The Bohr-Lindhard (B-L) model is used to describe the classical electron-capture process. The impact-parameter dependence of the capture probability is derived by considering the impact-parameter dependence of the collision time between ion and atom. This model limits the impact parameter to be less than the capture radius. In the framework of the B-L model, although the contribution from all impact parameters may be studied through the spatial distribution function of electrons, the multiple numerical integral has to be carried out. In this work, it is proposed that the impact-parameter dependence of the electron-capture probability can be given by a simple exponential decay function based on the (B-L) model. Electron-capture cross sections for Aq+(q=2~6)-H collisions, and double-electron-capture cross sections for Aq+(q=3~6)-He collisions are calculated at low and intermediate velocities. The calculated results are in good agreement with the existing experimental data. The energy and charge-state dependences of the electron-capture process are well described. This work can also be used to calculate the cross sections of electron capture from He and H targets by other ions with different charge states.
Effects of Doppler Broadening on Image Resolution for Compton Camera
Zhangyong SONG, Bingzhang ZHANG, Deyang YU
2021, 38(2): 215-220.   doi: 10.11804/NuclPhysRev.38.2020066
Abstract(59) HTML(19) PDF (3772KB)(11)
Abstract:
In heavy-ion cancer therapy, Compton camera is a promising tool for online monitoring of the range of ions. Compton camera uses crystal detectors to determine the positions and deposited energies of the $\gamma$-rays. This will further introduce the errors and affect the actual imaging resolution of the Compton camera, due to the involved Doppler broadening effects influencing the image resolution. This work simulates the angular resolution measure originating from the Doppler broadening effects with Geant4 toolkit for 150 and 511 keV gamma, respectively, in different crystal materials. After optimizing the back-projection algorithm and improving the voxel in imaging interspace, the image resolution can be achieved better than 1.0 mm. An approximate formula is also being proposed to evaluate the image resolution based on the angular resolution measure.
Nuclear Energy and Nuclear Data
Study of the 56,54Fe(n, α)53,51Cr, 56,54Fe(n, p)56,54Mn Cross Sections and Universal Parameter Optimization
Dongying HUO, Changqi LIU, Chao HAN, Kang WU, Zhijie HU, Zhiming HU, Xiaoxue YU, Zeen YAO, Zheng WEI
2021, 38(2): 221-228.   doi: 10.11804/NuclPhysRev.38.2020075
Abstract(58) HTML(16) PDF (3616KB)(13)
Abstract:
Based on the influence "hydrogen bubbles" and "helium bubbles", which are produced by the neutron induced reactions on Fe, of the new nuclear energy utilization system, the 56,54Fe(n, α)53,51Cr, 56,54Fe(n, p)56,54Mn cross sections are calculated in this work. The physical model (including energy level density, Correction, nuclear temperature, optical potential parameters, etc.) parameters were adjusted according to the existing experimental data and evaluation data of 56,54Fe(n, α)53,51Cr, 56,54Fe(n, p)56,54Mn cross sections, and a set of universal parameters were obtained. Based on the adjusted parameters, the TALYS program is used for calculating 56,54Fe(n, α)53,51Cr, 56,54Fe(n, p)56,54Mn reaction datas, including energy differential cross section and double differential cross section. Furthermore, the results are all in good agreement with the experimental data and evaluation data in the region of incident neutron energy from 0 to 175 MeV. By obtaining the universal parameters, new method was added to our nuclear reaction theory and laid the foundation for the nuclear data evaluation.

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