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Temperature and Radiation Performance of 4H-SiC Detector
Yaofeng ZHANG, Yuanyuan DU, Chunlei ZHANG, Ligang CAO, Xiaofei LAN, Yongsheng HUANG
 doi: 10.11804/NuclPhysRev.41.2023CNPC08
Abstract(0) HTML(0) PDF (0KB)(0)
Schottky diodes are fabricated using 100 µm thick 4H-SiC epitaxial wafers with Ohmic and Schottky contacts, and packaged as SiC detectors to meet the requirements of high temperature and radiation environments. The current-voltage (I-V) curves are measured in the range of 25 ºC to 150 ºC. The experimental results show that the leakage current changes very little when the temperature is less than or equal to 105 ºC. The change rate of leakage current is 0.33%/ºC, when the reverse bias is −500 V and the temperature rises from 25 ºC to 105 ºC. The SiC detector is irradiated by 60Co source in Peking University. The I-V characteristics of the SiC detector are compared before and after the irradiation experiment with total dose of 1 Mrad. The experimental data indicates that the leakage current has almost no significant change.
A Novel High-resolution Fast Magnetic Resonance Imaging Method Incorporating BEV/BPV Fusion Information
Jiayun CHEN, Xiaoqi WANG, Shirui QIN, Ran WEI, Deqi CHEN, Ke ZHANG, Ying CAO, Jianrong DAI, yuan TANG
 doi: 10.11804/NuclPhysRev.41.2023CNPC72
Abstract(85) HTML(18) PDF (3799KB)(14)
This study establishes a novel high-resolution fast magnetic resonance imaging(MRI) method that incorporates Beam Eye View(BEV) and Beam Path View(BPV) fusion information. Three liver metastasis patients undergoing MRI guided radiotherapy(MRgRT) were selected. A total of 31 200 frames of MRI images were acquired from each patient using two motion patterns: restricted abdominal motion using an abdominal compression belt(RAM group) and free breathing(FB group). Tumor tracking was performed using nearby vessels with clear boundaries, and the radial vector motion amplitude difference(∆R95) within the 95% confidence interval was calculated. The differences in ΔR95 between the RAM and FB groups in all fractions on the BEV/BPV plane were as follows: for Patient 1, they were all less than 0.58 mm; for Patient 2, they were greater than 2.57 mm; for Patient 3, they were 0.71 mm and 1.05 mm, respectively. The results indicate that the abdominal compression technique can effectively reduce tumor motion magnitude, and the tumor motion magnitude ΔR95 variation is highly individual-specific. This method can serve as an imaging basis for the tumor margin reduction in MRgRT.
2023, 40(4): 1-2.  
Abstract(318) HTML(38) PDF (393KB)(331)
Nuclear Physics
Three-dimensional QCD Phase Diagram in the pNJL Model
Lumeng LIU, Jun XU, Guangxiong PENG
2023, 40(4): 493-501.   doi: 10.11804/NuclPhysRev.40.2023025
Abstract(138) HTML(25) PDF (3051KB)(43)
Based on the three-flavor Polyakov-looped Nambu−Jona-Lasinio(pNJL) model, we have studied the structure of the three-dimensional QCD phase diagram with respect to the temperature, the baryon chemical potential, and the isospin chemical potential, by investigating the interplay among the chiral quark condensate, the pion condensate, and the Polyakov loop. While the pNJL model leads to qualitatively similar structure of the normal quark phase, the pion superfluid phase, and the Sarma phase as well as their phase boundaries, when compared to the NJL model, the inclusion of the Polyakov loop enlarges considerably the areas of the pion superfluid phase and the Sarma phase, and leads to critical end points at higher temperatures. With the contribution of the gluon dynamics effectively included, the present study is expected to give a more reliable prediction of the three-dimensional QCD phase diagram compared to that in the NJL model.
Fission Barriers of Actinide Isotopes in the Exactly Solvable Pairing Model
Xin GUAN, Wanqiu JIANG, Tiancong WANG, Jinhuan ZHENG, Meiyan ZHENG, Feng PAN
2023, 40(4): 502-510.   doi: 10.11804/NuclPhysRev.40.2023013
Abstract(85) HTML(26) PDF (2408KB)(17)
In this paper, we investigate the impact of pairing correlations on the fission barriers of Th, Pa, U, Np, Pu, Am, Cm, Bk, and Cf isotopes using an exactly solvable pairing model. Our results show that the pairing correlation plays a crucial role in determining the fission barrier height. Specifically, we find that the role of neutron and proton pairing in fission barrier heights is not universal across all isotopes, and the exact nature of the interaction depends on the specific isotopes being studied. Our calculated barrier heights are consistent with experimental data, and we propose using the odd-even mass difference(ground-state properties) and barrier height(excited-state properties) as experimentally observable quantities to determine the pairing interaction strengths in the fission process.
Structure and α Decay of Superheavy Nucleus 296Og
Fengzhu XING, Jianpo CUI, Yonghao GAO, Liqian QI, Yanzhao WANG, Jianzhong GU
2023, 40(4): 511-518.   doi: 10.11804/NuclPhysRev.40.2023059
Abstract(241) HTML(60) PDF (2006KB)(57)
The nuclear ground state properties of the superheavy nucleus 296Og, such as the potential energy surface, single-particle energy spectrum, two-neutron separation energy and α-decay energy, are studied with the volume, surface and mixed pairings based on the SLy4 interaction in the framework of the deformed Skyrme-Hartree-Fock-Bogoliubov(SHFB) theory. It is found that 1) The ground state shape of 296Og is nearly spherical with the volume and mixed pairings. However, the shape coexistence of 296Og is predicted with the surface pairing. 2) The super-deformed states are predicted by all of the three kinds of pairings. The binding energy, potential well depth and excitation energy of the super-deformed states are influenced by the pairings. At the same time, the surface pairing effect on the properties of the super-deformed states is the most evident. 3) The pairings have certain influence on the shell structure, two-neutron separation energy, α-decay energy and α-decay half-life of 296Og and the impact from the surface pairing is the strongest. Moreover, the order of magnitude of α-decay half-life is varied occasionally owing to the change of the α-decay energy caused by the pairings.
Structural Investigation in A ≈ 90 Mass Region and Comparison in Its Vicinity
Yiheng WU, Jingbin LU, Zhen REN
2023, 40(4): 519-526.   doi: 10.11804/NuclPhysRev.40.2022110
Abstract(68) HTML(15) PDF (2239KB)(10)
In the investigations of the level structure of $A \approx 90$ nuclei, whose numbers of protons and neutrons are close to the $Z = 40$ semimagic number and $N = 50$ magic number, have become a hot spot in nuclear physics. The aim of this work is to further probe the characteristics of single-particle excitation, core breaking, high-$j$ intruder states and isomeric states in the $A\approx 90$ mass region based on the existing experimental results. Investigations show that the low energy levels of the odd-$A$ nuclei originate from their neighboring even-even nuclei coupled to a valence nucleon. The systematics of the $2_{1}^{+}$ excitation energies and the values of ${\rm{E}}_{4_{1}^{+}}$/${\rm{E}}_{2_{1}^{+}}$ indicate that the $N = 56$ subshell closure may appear at $Z = 40$ (41) and disappear for $Z > 42$ nuclei. Furthermore, in this mass region, the strong ${\rm{E}}2$ transitions at low or medium spins are interpreted as the recoupling of the pure protons in ($f_{5/2}^{}$, $p_{3/2}^{}$, $p_{1/2}^{}$, $g_{9/2}^{}$) orbits, and the strong $M1$ transitions are explicated by moving proton from the ($f_{5/2}^{}$, $p_{3/2}^{}$, $p_{1/2}^{}$) orbits to the $g_{9/2}^{}$ orbit, coupling to a neutron excitation from the $g_{9/2}^{}$ orbit across $N = 50$ closed shell into the $d_{5/2}^{}$ orbit. The isomeric states in odd-$A$ nuclei with $N = 50 $ (51) can be interpreted as a spin-aligned configuration in which a single neutron or proton couples with a fully aligned proton pair in the $\pi g_{9/2}^{}$ orbit.
Intermittency and Fractals in Fragmenting Processes
Wenxia WANG, Yongzhong XING, Hongfei ZHANG, Yiyan ZHAO
2023, 40(4): 527-533.   doi: 10.11804/NuclPhysRev.40.2022101
Abstract(119) HTML(44) PDF (1875KB)(27)
In order to understand more comprehensively the dynamical mechanism of the multifragmentation taking place in heavy ion collision at intermediate energies, in the present paper, with help of the factorial moment method, we analyze the concrete behaviors of intermittent chaos and fractal in the distributions of the fragments in the reaction final states and the primary fragments formed during the fragmentation process, by simulating some collisions within the framework of the isospin dependent quantum molecular dynamics model. Our results show that 1) the fluctuations of the distribution of these fragments multiplicity are multi-fractal rather than mono-fractal, and 2) the intermittent exponent reaches its maximum at the stage of the multi-fragmentation taking place during the collisions. The universality of these features is verified by studying the similar colliding systems with the same analysis method. These new features we have revealed here not only help us to deepen our understanding of the dynamic mechanism of the multifragmentation, but also enrich our knowledge of nonlinear dynamics.
Beam Dynamic Design of IH-DTL with Built-in Permanent Magnet Quadrupole Lens
Bo ZHANG, Yao YANG, Yu TANG, Yuhan ZHAI, Huanyu ZHAO
2023, 40(4): 534-540.   doi: 10.11804/NuclPhysRev.40.2022025
Abstract(128) HTML(167) PDF (8118KB)(112)
Based on KONUS dynamics, the beam dynamic design of a compact IH-DTL with built-in permanent magnet quadrupole lens was completed. The DTL consists 37 acceleration cells and two sets of permanent magnet quadrupole lenses, enabling the acceleration of C6+ ion beam of 20 emA from 0.5 MeV/u to 4.0 MeV/u. Throughout the design process, significant focus was placed on optimizing the voltage of the acceleration gap, the parameters of the quadrupole magnet, the phase setting of the beam injection, and the energy and phase setting of the 0-degree reference particle to control the transverse and longitudinal emittance growth of the high-current ion beam in the low-energy range. Consequently, transverse normalized RMS acceptance of the IH-DTL reaches 0.37 πmm · mrad, and the transmission efficiency exceeds 95%.
Simulation on Temperature Field of Laser-annealed Copper-based Niobium Thin Film by Finite Element Analysis Method
Changlin WANG, Teng TAN, Pingran XIONG, Didi LUO, Tongtong ZHU, Qingwei CHU
2023, 40(4): 541-546.   doi: 10.11804/NuclPhysRev.40.2022086
Abstract(128) HTML(35) PDF (2447KB)(91)
Copper-based niobium thin film cavity is one kind of superconducting radio frequency(SRF) cavities developed from bulk niobium cavity. This new type of cavity has similar SRF properties to the pure niobium cavities but is more economical, mechanically stable, and thermally stable, making it promising for industrial SRF applications. However, the inevitable surface defects of niobium film on the surface of Nb/Cu cavities induce extra power dissipation, and require post-treatment before cavity operation. Near-surface annealing of SRF cavity by nanosecond high-intensity pulsed laser is an emerging surface treatment technology for SRF cavity. Using high power and short pulsed laser with peak power flux exceeding 100 MW/cm2 to locally recrystallize the surface can reduce the surface roughness, increase the grain size and eliminates some surface defects, so as to obtain better surface RF properties. At present, the type of laser selected in this direction is mainly the solid-state laser with high peak power, which has a very low average power, not practical for the actual superconducting cavity with an m2 inner wall surface area. To solve this issue, a whole-cavity laser processing system based on a kW-level power nanosecond pulse fiber laser has been established by the Surface Treatment Research Team of the Institute of Modern Physics. In this study, finite element simulation was conducted with the parameters of the system to investigate the temperature distribution on the surface and inside the material under near-actual working conditions. Combined with the material properties, the laser surface treatment effect of pure niobium material was simulated. This study preliminarily confirms the feasibility of using nanosecond pulse laser for complete annealing of the inner wall of superconducting cavities, and provides an effective method for achieving better RF superconducting performance.
The Development of BTracker, a Simulation Code for Beam Losses From Magnet Power Failure
Hang REN, Jiancheng YANG, Geng WANG, Guodong SHEN, Liping YAO, Jie LIU, Shuang RUAN, Lina SHENG
2023, 40(4): 547-554.   doi: 10.11804/NuclPhysRev.40.2022100
Abstract(96) HTML(19) PDF (3632KB)(23)
The booster ring(BRing) of High Intensity heavy-ion Accelerator Facility(HIAF) is characterized by high intensity and high energy. Failures of key equipment such as magnets and RF system will lead to significant beam losses and damage to the accelerator. A beam dynamics simulation code BTracker is developed to study beam losses under equipment failures and beam dynamics during beam dumping for the HIAF machine protrection. With this code, beam loss distribution under power failure of dipole and quadrupole magnets is simulated, and the results are benchmarked with MAD-X code. In addition, BTracker provides user-friendliness, interface flexibility and high performance to meet the requirements of machine protection simulation for HIAF-BRing.
Nuclear Technology
Studies on the add-back Performance of a Clover Type HPGe Detector
Pengcong MA, Pengsong ZHENG, Quanbo ZENG, Hao HUANG, Fanfei ZENG, Jilehu GADA, Xin MA, Yunhua QIANG, Jianguo WANG, Guangshun LI
2023, 40(4): 555-559.   doi: 10.11804/NuclPhysRev.40.2023023
Abstract(124) HTML(34) PDF (1816KB)(12)
High Purity Germanium(HPGe) detectors have been widely used in γ spectroscopy. The add-back performance of Clover type HPGe detector is studied based on Monte Carlo simulation. We have simulated the energy spectrum from a single crystal and the Compton scattering probability of γ ray between different crystals. Good agreements have been achieved between the simulated results and experimental data. Afterwards the add-back performance is further studied in terms of γ ray multiplicity and the distance between γ source and the detector. The studies revealed that the higher multiplicity ($M = 6 $) affects slightly on the add-back factor at 25 cm distance, mainly in the low energy region. With the distance decreases, the add-back factor changes dramatically. Typically, in the situation of 5 cm distance and $M = 6 $, the add-back analysis is not recommended.
Compact AMS Measurement Technology for 129I
Wenhui ZHANG, Qingzhang ZHAO, Ming HE, Chengli XIU, Kangning LI, Yiwen BAO, Wei GUO, Jianliang LI, Shengyong SU, Qubo YOU
2023, 40(4): 560-565.   doi: 10.11804/NuclPhysRev.40.2023110
Abstract(78) HTML(30) PDF (3799KB)(10)
A new compact accelerator mass spectrometer(AMS) facility, used for 14C, 129I, 239Pu, etc. measurement, has been successfully established by China Institute of Atomic Energy(CIAE) recently. As 129I is a commonly used nuclide for environmental tracing, the performance of 129I measurement is crucial for the applications of the facility. After systematic research, 129I measurement technologies of the compact AMS has been established. The measurement sensitivity and the measurement accuracy of 129I/127I reached to 1.5×10-14 and 0.81%, respectively. The measurement results show that the compact AMS has reached the international advanced level and can lay the solid foundation for the application of 129I in fields like nuclear environmental monitoring and marine pollution tracing.
Design and Verification of Fluorescence Detector for Rapidly Acquiring the Bragg Peak Position of Carbon Ion Beam
Yujie KANG, Yazhou LI, Jingfen YANG, Xinguo LIU, Zhongying DAI, Pengbo HE, Qiang LI
2023, 40(4): 566-571.   doi: 10.11804/NuclPhysRev.40.2022128
Abstract(93) HTML(20) PDF (1648KB)(9)
A design scheme of fluorescence detector was proposed for rapidly acquiring the Bragg peak position of carbon ion beam in scintillator material. Based on the characteristic of scintillator emitting fluorescence under the irradiation of carbon ion beam, CMOS camera is applied to acquire the image of fluorescent intensity distribution on the side of a thin scintillator, and then the Bragg peak position of carbon ion beam in the scintillator material is quickly obtained by analyzing the fluorescent image. According to the scheme, a fluorescence detector was developed and then used for experimental measurement under the irradiation of carbon-ion uniform fields and pencil beams with different energies. The experimental results showed that the Bragg peak position of the carbon ion beams could be clearly observed from the fluorescent image obtained by the detector. Moreover, the method of Monte Carlo simulation was used to calculate the depth dose distribution of carbon ion beams under the experimental conditions mentioned above. It was found that there was a penetration depth difference between the measured and calculated Bragg peak positions of carbon ion beam in the scintillator material by the fluorescence detector and the Monte Carlo simulation due to the difference between their settings, but the differences under the various irradiation conditions were nearly the same. Therefore, the experimental measurements and Monte Carlo simulations verified that the fluorescence detector scheme could be used for quickly acquiring the Bragg peak position of carbon ion beam in the scintillator material definitely, which provides a substantial basis for establishing a fast fluorescence detector-based quality assurance measurement method in carbon ion radiotherapy.
Research on Intelligent Optimization of Reactor Radiation Shielding Design Based on FCNN-NSGA-Ⅲ
Xiaomeng LI, Zhifeng LI, Yingming SONG, Song HAN, Long GUI
2023, 40(4): 572-578.   doi: 10.11804/NuclPhysRev.40.2022118
Abstract(120) HTML(50) PDF (3655KB)(6)
In order to solve the problems of low efficiency and high error in traditional radiation shielding design, an intelligent optimization method for reactor shielding design based on the coupling of the fully connected neural network (FCNN) and the third generation non dominated sorting genetic algorithm (NSGA-III) was proposed. Taking a molten salt reactor as an example, the reactor shielding optimization model is established and Monte Carlo software is used to calculate a large number of samples. FCNN is used to machine learn the calculation data, and the multi-dimensional nonlinear mapping relationship between input layer parameters and output layer parameters is established. The neural network prediction results are used as the basis for calculating the fitness function. Based on NSGA-III, multi-objective optimization is carried out to obtain the Pareto optimal solution for multi-objective optimization of radiation shielding design. The results show that the FCNN coupled NSGA-III method performs well in solving multi-objective optimization problems and can be applied to reactor shielding design.
Testing and Evaluation of a Waveform Digitization System Based on TIADC Technique
Yi CAO, Jiajun QIN, Lei ZHAO, Qi AN
2023, 40(4): 579-588.   doi: 10.11804/NuclPhysRev.40.2022102
Abstract(68) HTML(19) PDF (4948KB)(2)
Time-Interleaved Analog-to-Digital Conversion(TIADC) is one of the most important techniques in the design of high-speed waveform digitization systems, it can multiple the sampling rate of a sampling system. However, there are mismatch errors between different sampling channels, which will make the dynamic performance of a TIADC system significantly lower than that of a single ADC. Therefore, mismatch errors should be corrected in TIADC system design. To evaluate the quality of the system design and promote the next optimization design, it is necessary to conduct scientific performance test and evaluation on the TIADC system. In this work, aiming at the test and evaluation, the performance indexes and test methods of TIADC system are introduced in detail, a series of performance tests of the system are completed, and mismatch errors are corrected based on perfect reconstruction algorithm. The test results show that the system can achieve an equivalent 5 Gsps sampling rate and can realize mismatch error correction in a wide band based on the proposed mismatch error correction method. After correction, the dynamic performance of the TIADC system is significantly enhanced compared with that without correction. For example, the Effective Number of Bits(ENOB) of the proposed system reaches 9.2 bits at 247 MHz, 8.9 bits at 857 MHz, which is equivalent to the performance index of a single ADC.
Design of Multi-channel High Voltage Protection System for High Purity Germanium Detector
Jingzhe ZHANG, Wenkai LI, Xiaorui WANG, Linbo MA, Bo ZHANG, Jinfeng XIAO, Meiyang LIU, Xiangxiang GOU, Jiuyao ZHAO, Chengcheng SHI
2023, 40(4): 589-598.   doi: 10.11804/NuclPhysRev.40.2023017
Abstract(100) HTML(29) PDF (2411KB)(9)
High purity germanium detectors are widely employed for gamma ray measurements in nuclear spectroscopy experiments at the moment. The application of high voltage during operation necessitates stringent monitoring and control conditions. Traditional manual observation-based monitoring methods prove inefficient and slow in response, often resulting in varying degrees of detector damage. To address this issue, real-time temperature changes in the high purity germanium detector are converted into resistance value measurements using Pt100 sensors. Subsequently, a high-voltage module controller is designed and implemented to establish a protection system for the high purity germanium detector's high voltage supply. The hardware and logic of the controller are meticulously designed, while noise reduction algorithms are studied to enhance performance. Finally, circuit tests validate that the developed system automatically cuts off the high voltage when the detector temperature exceeds an upper threshold and restores it when the temperature falls below a lower threshold. This system effectively meets real-time protection requirements for high-voltage applications with respect to high purity germanium detectors.
Testing of a 10 bit 20 MSPS Pipeline ADC
Tianliang DU, Yi QIAN, Qianshun SHE, Tianlei PU, Hongyun ZHAO, Jie KONG, Mingyu YANG, Zhikun SUN, Zhipeng SUN, Junwei YAN, Jiapeng XU
2023, 40(4): 599-606.   doi: 10.11804/NuclPhysRev.40.2023002
Abstract(96) HTML(27) PDF (10281KB)(5)
For the low power and digital readout requirements of plastic scintillation detector(PSD), a multi-channel 10 bit 20 MSPS Pipeline Analog-to-Digital Converter(ADC) chip is developed. In order to evaluate the performance of the ADC chip, a systematic test is needed. In the work of this paper, a test system is developed, which included the hardware design of the circuits, the design of the FPGA firmware and the analysis programme. The ADC chip was systematically tested and analysed according to IEEE standards.The test results indicate that, when the input signal frequency is in baseband range, the performance of the ADC chip meets the design requirements, and the Effective Number of Bit(ENOB) is close to 8.0 bit. The Integral nonlinearity(INL) is 0.75 LSB, and the differential nonlinearity(DNL) is 1.09 LSB, which provides strong support for future optimization design and parameter improvement of the ADC chips.
Cross Discipline
Biological Effects of High-Energy Carbon Ion Beam Irradiation on Seedlings of Scutellaria baicalensis
Linghui GE, Yuanmeng WANG, Xiao LIU, Yan DU, Jingmin CHEN, Xuehu LI, Man WANG, Yifan ZHANG, Fusheng WANG, Ling JIN, Libin ZHOU
2023, 40(4): 607-618.   doi: 10.11804/NuclPhysRev.40.2022120
Abstract(115) HTML(38) PDF (2857KB)(8)
To explore the effects of high-energy heavy ion beams irradiation on the physiological and growth characteristics of Scutellaria baicalensis Georgi seedlings, different doses of carbon ion beam with total energy of 967 MeV were selected to irradiate seedlings to measure the survival rate, seedling height, number of leaves, number of branches, biomass, root-shoot ratio, antioxidant enzyme activity, photosynthetic characteristics and content of secondary metabolites. The results showed that the semi-lethal dose of seedlings was 32.82 Gy. The seedling height, number of leaves, number of branches, and biomass of Scutellaria baicalensis increased under 5 and 10 Gy, but decreased under 30 Gy compared with the control group. The activities of superoxide dismutase (SOD) and peroxidase (POD) in all treatment groups increased to reduce the damage of reactive oxygen species caused by irradiation. The content of chlorophyll in leaves decreased with the dose within 6 weeks after irradiation; the content of total chlorophyll, net photosynthetic rate and stomatal conductance of leaves increased under 5 and 10 Gy in 9 weeks after irradiation. In addition, the accumulation of total flavonoids and baicalein in the root were promoted under 10 Gy. These results indicated that 10 Gy heavy ion beams not only stimulated the growth, but also increased the content of medicinal ingredients in Scutellaria baicalensis. The study explored the contemporary biological effects of heavy ion beams radiation on Scutellaria baicalensis Georgi, which provides a basis for the follow-up research on irradiation stimulation effects and radiation breeding of Scutellaria baicalensis Georgi.
Influence of Cell Survival Experiment Data Processing on the Calculated Values of Biological Dose Distribution in Carbon Ion Radiotherapy
Xingzhu DUAN, Yuanyuan MA, Hui ZHANG, Zhongying DAI, Qiang LI, Xinguo LIU
2023, 40(4): 619-627.   doi: 10.11804/NuclPhysRev.40.2022127
Abstract(77) HTML(24) PDF (1923KB)(6)
The influence of different data processing methods on the fitting values of linear square(LQ) model parameters and the calculated values of biological dose distribution used in treatment planning were investigated in the cell cloning survival experiment. Four sets of LET-α and LET-β data were obtained based on the LQ model fitted to the data from the clonogenic survival experiments of carbon ion irradiated cells from T98G cells, according to whether the standard deviation of the cell survival rate was taken into account, and the plating efficiency was taken into account in two different ways, respectively, and three of them were selected to build the basedata of three datasets of the matRad treatment planning system for the treatment planning study. When only the 0 Gy plating efficiency was considered, whether the fitting considered the standard deviation of survival rate had little influence on the α value when the LET was low, but had a greater influence on the β value; With the LET getting larger, it had a greater impact on the α value and a lesser impact on the β value. When considering the standard deviation of survival rate, the deviations of fitting results in 2 different ways to consider the plating efficiency were small. Except for 200 keV/μm, the relative deviation of α values between the two groups did not exceed ±10%. Planset2 always overestimated Dmax, Dmin and D95 compared to Planset1. The results illustrate that whether the standard deviation of survival rate were considered or not had a greater influence on the fitted α, β coefficients than considering the plating efficiency in 2 different ways. The relative deviation range of biological dose distribution’s calculation values among different datasets in the treatment planning system was smaller than the relative deviation range of α and β values of each group obtained by fitting the experimental data.
An Investigation of the SEU Response of SRAM in a 22 nm FDSOI Technology
Jinhu YANG, Peixiong ZHAO, Liang WANG, Yajiao LIU, Zhenhua ZHANG, Yang JIAO, Shiwei ZHAO, Pengfei ZHAI, Youmei SUN, Jie LIU
2023, 40(4): 628-635.   doi: 10.11804/NuclPhysRev.40.2022121
Abstract(100) HTML(50) PDF (12463KB)(7)
The Fully Depleted Silicon on Insulator(FDSOI) process is considered an ideal semiconductor technology for producing highly reliable aerospace electronic devices. Therefore, a comprehensive understanding of the single event effects mechanism in FDSOI devices is of theoretical significance for radiation-hardened design. This paper focuses on 22 nm FDSOI SRAM test devices and investigates the impact patterns and physical mechanisms of different heavy ions and electrical parameters on the sensitivity of Single Event Upset(SEU) in the devices. Experimental results indicate that in regions with high Linear Energy Transfer(LET) values, the proportion of Multi-Cell Upset(MCU) can reach 20%. Additionally, the core voltage has a relatively minor impact on the type proportion and occurrence probability of SEU. The incidence angle of heavy ions significantly increases the SEU cross-section of the devices, with a 130% difference observed when heavy ions are incident along parallel and perpendicular directions to the substrate well region. Therefore, when modeling Single Event Effect in FDSOI devices and designing for radiation hardening, it is imperative to consider the influence of non-direct diffusion charge sharing mechanisms and substrate potential distortion-triggered parasitic current mechanisms on the transient ionization charge collection process.
UV Spectral Lines and X-ray Spectra Induced by 129Xe20+ Impacting on the Ta Surface
Yijun WANG, Ying ZHANG, Xiaoan ZHANG, Xianming ZHOU, Cexiang MEI, Changhui LIANG, Lixia ZENG, Yaozong LI, Yu LIU, Qianlan XIANG, Hui MENG, Yanning ZHANG
2023, 40(4): 636-642.   doi: 10.11804/NuclPhysRev.40.2023037
Abstract(94) HTML(33) PDF (2040KB)(117)
Using 129Xe20+ ions with kinetic energy of 100~500 keV and 1.2~6.0 MeV respectively incident on the Ta target, the spectral lines of transition radiation are measured between complex electronic configurations of excited atoms or ions during the interaction of incident ions at different velocities with the Ta surface. The ultraviolet spectral lines of the deexcitation radiation from multiple high Rydberg states to low energy state 5p5(2P°3/2)6s of Xe atoms are measured as the kinetic energy of Xe20+ranges from 100 to 500 keV, the principal quantum number of valence electrons of Rydberg states is $n = 15 $, 13, 11, and 8, respectively. The results show that as the incident ion velocity increases, the single particle fluorescence yield of the the high Rydberg states spectral line of Xe atoms decreases. During this collision process, the single particle fluorescence yield increases of the spectral lines of the excited target atoms and ions with the increase of the incident ion velocity. When the ion kinetic energy increases to 1.2~6.0 MeV, the single particle yield of the Ta characteristic X-rays (Mα1, Mα2) increases with the velocity of the incident ions. When the kinetic energy of the incident ion is 6 MeV, the L X-ray spectra are measured of the Xe atom during the collision between Xe20+and the target atom.
Nuclear Energy and Nuclear Data
Application of First Principles in Calculation of Thermal Neutron Scattering Cross Section
Lipeng WANG, Xinyi ZHANG, Duoyu JIANG, Tianliang HU, Lu CAO
2023, 40(4): 643-650.   doi: 10.11804/NuclPhysRev.40.2022115
Abstract(110) HTML(31) PDF (4224KB)(9)
The calculation of thermal neutron cross section for thermal neutron scattering materials in the field of nuclear engineering is based on the first principle. This study utilizes Al and Bi metals as examples for the determination of thermal neutron cross sections. The frozen phonon method and density functional perturbation method are applied to calculate the thermal neutron cross sections for Al and Bi, respectively. Phonon dispersion relation and phonon density of state are computed using VASP and PHONONY. Subsequently, coherent scattering for Bi is incorporated into LEAPR using NJOY to generate the thermal neutron scattering cross-section libraries for Al and Bi. The results reveal that, in the case of Al, the thermal neutron scattering cross section obtained using the density functional perturbation theory is in better agreement with ENDF8.0 compared to the frozen phonon method. Conversely, for Bi, the density functional perturbation method eliminates the imaginary frequency phenomenon observed in the frozen phonon method, resulting in thermal neutron scattering results that align well with experimental data. The paper proposes a more fundamental and predictable method for generating thermal neutron cross-sections by exploring the internal characteristic mechanism of the material, thus laying a theoretical foundation for studying the thermal mechanisms of new reactor nuclear materials..
Study on Coupled Heat Transfer Between ADS Spallation Target and Subcritical Reactor
Jian SONG, Huan JIA, Hanjie CAI, Xunchao ZHANG, Yuan HE
2023, 40(4): 651-659.   doi: 10.11804/NuclPhysRev.40.2022091
Abstract(91) HTML(53) PDF (4306KB)(7)
Through the thermal coupling between ADS liquid lead bismuth target and lead based subcritical reactor, this paper studies the effect of whether a thermal barrier layer is added between the target and the reactor, the thermal conductivity and thickness of the layer, and when a gas thermal barrier layer is added, gas pressure on the heat flow between target and reactor. The study found that adding a thermal barrier layer can reduce the heat flow after coupling. Adding a gas layer can significantly reduce the heat flow, and allow the flow velocity of lead-bismuth in both target and reactor and the temperature difference between target and reactor to fluctuate over a wider range. The heat flow is proportional to the thermal conductivity of the thermal barrier layer and inversely proportional to the thickness of the layer. The thickness of the gas layer can be selected between 0.06 m and 0.08 m. The pressure of the gas thermal barrier is in the range of 0.1 to 10 Pa, and the heat flow varies significantly with the pressure. Therefore, the pressure of the gas thermal barrier layer can be selected to be about 0.1 Pa.
Development of a Heat Exchanger Module for a Transient Safety Analysis MPC_LBE Program for Lead-bismuth Reactors
Qiwen PAN, Wenlan OU, Zhixing GU, Zhengyu GONG, Jianing DAI
2023, 40(4): 660-667.   doi: 10.11804/NuclPhysRev.40.2022125
Abstract(270) HTML(120) PDF (3091KB)(10)
As one of the fourth-generation advanced nuclear energy systems, Lead-Bismuth Eutectic(LBE) cooled reactor has excellent neutron economy and inherent safety. To improve its compactness and safety, the main coolant system of LBE-cooled reactor tends to adopt the integrated pool structure design concept, but this design concept also introduces complex thermal hydraulic problems. To solve the above issues, the multi-physics coupling transient safety analysis code for LBE-cooled reactor MPC_LBE was developed, but this code uses a constant temperature simplified model which are not able to simulate the heat exchange process between the first and second circuits, and the accident transient simulation is rather conservative which deviating from the actual condition. To solve this problem, the numerical simulation method of the heat exchanger module for LBE-cooled reactor was carried out in this paper. A one-dimensional numerical calculation models were employed for the primary side, pipe wall and secondary side of heat exchanger, and the numerical heat transfer model was constructed. Finally, the heat exchanger module was coupled with the MPC_LBE code by external explicit means. For the heat exchanger numerical calculation module, steady-state verification and time step sensitivity analysis were performed separately, and the results show that the time step sensitivity of the explicit coupling strategy is large, while the time step setting of the implicit coupling strategy has almost no effect on the simulation results. For the new MPC_LBE program coupled with the numerical calculation module of the heat exchanger, the steady-state simulation application of the natural cycle lead-bismuth reactor was carried out.
Physical Design Analysis of Offshore Stationary Lead Reactor Based on OpenMC
Yujie TAO, Wei JIANG, Cunfeng YAO, Long GU, Lu ZHANG
2023, 40(4): 668-675.   doi: 10.11804/NuclPhysRev.40.2022129
Abstract(77) HTML(40) PDF (5432KB)(10)
The offshore nuclear energy platform, characterized by low operating costs, reliable energy supply, and environmental friendliness, can provide stable and reliable energy for the development of offshore oil and gas resources and the livelihood support of personnel. The offshore fixed lead-cooled reactor platform, addressing the demand for stable energy supply in China's maritime regions, aims to propose a conceptual design for a reactor with an electrical power output of 20 MW, a service life of 40 years, and no need for replacement of materials throughout its entire lifespan. This paper uses the CAR-3600 benchmark and validates the applicability of the burnup module of the open-source Monte Carlo program OpenMC in a lead-cooled fast reactor. A comparison of the calculation results for the offshore fixed lead-cooled reactor core between the OpenMC and MCNP programs is conducted, analyzing the differences in results obtained using different nuclear databases in the OpenMC program and exploring possible reasons for these differences. The research results indicate that the burnup module of the OpenMC program is applicable in fast reactors. The calculation results of OpenMC and MCNP programs are close, and a comparative validation of the design scheme for the offshore fixed lead-cooled reactor is carried out using different simulation software. The simulation also reveals that due to differences in capture cross-sections of 235U and 238U, the reactivity fluctuations obtained from the ENDF/B-VIII.0 library and the JEFF-3.3 library are larger than the design target of $ 1\; \$$, requiring further optimization of the scheme to reduce burnup reactivity fluctuations.
Development and Validation of Resonance Self-shielding Cross Section Calculation Module of the Unresolved Energy Region in AXSP Program
Feng ZHOU, Xubo MA, Chen ZHANG, Yongwei YANG
2023, 40(4): 676-683.   doi: 10.11804/NuclPhysRev.40.2022126
Abstract(252) HTML(37) PDF (2049KB)(7)
In the unresolved energy region, due to the dense distribution of resonance peaks, the precise resonance parameter data cannot be obtained due to the resolution limitation of the nuclear measuring instrument. For this energy region, the Evaluation Nuclear Data Files only provides the average values and distribution functions of the resonance parameters. In order to consider the resonance self-shielding effect in the unresolved resonance energy region, it is necessary to calculate the effective self-shielding cross-section based on these parameters with probability distribution properties. For the treatment of resonance self-shielding effect in the unresolved resonance energy region, a probability table module PUnresXS and an effective self-shielding cross-section calculation module UnresXS were developed in the advanced nuclear cross-section processing program AXSP based on the "Ladder Sampling" and integral statistics principle method. The algorithms in the probability table calculation module were also improved. By comparing with the reference solution obtained from NJOY2016 calculations, the PUnresXS and UnresXS modules were independently validated. The results showed that the efficiency of the probability table module was improved by more than 60%, the keff and neutron spectrum were in good agreement with the reference solution. The developed resonance self-shielding cross-section calculation module exhibited similar accuracy to NJOY2016, demonstrating the correctness of these two modules developed in the AXSP program.


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