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Electronic effects on radiation damage inα-iron:A molecular dynamics study

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Chinese physics B 2024年第3期33卷 521-529页

作者：江林李敏付宝勤崔节超侯氢 Key Laboratory for radiation physics and Technology Institute of Nuclear Science and TechnologySichuan UniversityChengdu 610064China

Iron(Fe)-based alloys,which have been widely used as structural materials in nuclear reactors,can significantly change their microstructure properties and macroscopic properties under high flux neutron irradiation during operation,thus,the problems associated with the safe operation of nuclear reactors have been put forward *** this work,a molecular dynamics simulation approach combined with electronic effects is developed for investigating the primary radiation damage process inα-***,the influence of electronic effects on the collision cascade in Fe is systematically evaluated based on two commonly used interatomic potentials for *** simulation results reveal that both electronic stopping(ES)and electron-phonon coupling(EPC)can contribute to the decrease of the number of defects in the thermal spike *** application of ES reduces the number of residual defects after the cascade evolution,whereas EPC has a reverse *** introduction of electronic effects promotes the formation of the dispersive subcascade:ES significantly changes the geometry of the damaged region in the thermal spike phase,whereas EPC mainly reduces the extent of the damaged ***,the incorporation of electronic effects effectively mitigates discrepancies in simulation outcomes when using different interatomic potentials.

关键词： radiation damage electronic effects molecular dynamics simulation α-iron

The biochemical behavior and mechanism of uranium(Ⅵ)bioreduction induced by natural Bacillus thuringiensis

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Journal of Environmental Sciences 2024年第2期136卷 372-381页

作者： Shunzhang Chen Junyuan Gong Yanxia Cheng Yuqi Guo Feize Li Tu Lan Yuanyou Yang Jijun Yang Ning Liu Jiali Liao Key Laboratory of radiation physics and Technology of the Ministry of Education Institute of Nuclear Science and TechnologySichuan UniversityChengdu 610064China

For a broader understanding of uranium migration affected by microorganisms in natural anaerobic environment,the bioreduction of uranium(Ⅵ)(U(Ⅵ))was revealed in Bacillus thuringiensis,a dominant bacterium strain with potential of uranium-tolerant isolated from uranium contaminated *** reduction behavior was systematically investigated by the quantitative analysis of U(Ⅳ)in bacteria,and mechanism was inferred from the pathway of electron *** anaerobic conditions,appropriate biomass and sodium lactate as electron donor,reduction behavior of U(Ⅵ)induced by *** was restricted by the activity of lactate dehydrogenase,which was directly affected by the initial pH,temperature and initial U(Ⅵ)concentration of bioreduction *** of U(Ⅵ)was driven by the generation of nicotinamide adenine dinucleotide(NADH)from enzymatic reaction of sodium lactate with various *** transmission of the electrons from bacteria to U(Ⅵ)was mainly supported by the intracellular NADH dehydrogenase-ubiquinone system,this process could maintain the biological activity of cells.

关键词： Uranium Bacillus thuringiensis Bioreduction Electron transmission

Designing highly transparent cerium doped Y2O3 ceramics with high mechanical and thermal properties for UV-shielding in extreme conditions

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Journal of Advanced Ceramics 2024年第7期13卷 1032-1042页

作者： Cong Zhang Jianqi Qi Xiaolan Zhou Zhonghua Lu Tiecheng Lu College of physics Sichuan UniversityChengdu 610064China Key Laboratory of High Energy Density physics of Ministry of Education Sichuan UniversityChengdu 610064China Key Laboratory of radiation physics and Technology of the Ministry of Education Sichuan UniversityChengdu 610064China

Ultraviolet(UV)radiation poses risks to both human health and *** response to the urgent demand for UV-shielding across various applications,extensive endeavors have been dedicated to developing UV-shielding materials spanning from wide-bandgap semiconductors to organo-inorganic composite ***,existing UV shielding materials,though suitable for daily use,cannot meet the demands of extreme *** this work,we incorporated CeO_(2)as a UV absorber into Y_(2)O_(3)transparent ceramics for *** effect of CeO_(2)concentration on the optical,mechanical,and thermal properties of Y_(2)O_(3)ceramics was systematically *** findings indicate that CeO_(2)serves not only as a UV absorber but also as an effective sintering aid for Y_(2)O_(3)transparent *** 5 at%Ce-doped Y_(2)O_(3)transparent ceramics exhibit the optimal optical quality,with in-line transmittance of~77%at 800 *** introduction of Ce shifted the UV cutoff edge of Y_(2)O_(3)transparent ceramics from 250 to 375 nm,which was attributed to the visible band absorption of Ce^(4+).This shift grants UV shielding capabilities to Y_(2)O_(3)transparent ceramics,resulting in 100%shielding for ultraviolet C(UVC,100-280 nm)and ultraviolet B(UVB,280-320 nm)and~95%shielding for ultraviolet A(UVA,320-400 nm).The service stability(optical properties)under various corrosive conditions(acid,alkali,UV irradiation,and high temperature)was investigated,confirming the excellent stability of this transparent ceramic UV-shielding material.A comparison of the performance parameters of transparent ceramics with those of traditional UV shielding materials such as glasses,films,and coatings was *** work provides innovative design concepts and an effective solution for UVshielding materials for extreme conditions.

关键词： ultraviolet(UV)-shielding transparent ceramics bandgap engineering thermal properties optical properties

A compact X-band backward traveling-wave accelerating structure

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Nuclear Science and Techniques 2024年第5期35卷 13-29页

作者： Xian-Cai Lin Hao Zha Jia-Ru Shi Qiang Gao Fang-Jun Hu Qing-Zhu Li Huai-Bi Chen Department of Engineering physics Tsinghua UniversityBeijing 100084China Key Laboratory of Particle and radiation Imaging(Tsinghua University) Ministry of EducationBeijing 100084China

Very high-energy electrons(VHEEs)are potential candidates for FLASH radiotherapy for deep-seated *** proposed a compact VHEE facility based on an X-band high-gradient high-power *** this study,we investigated and realized the first X-band backward traveling-wave(BTW)accelerating structure as the buncher for a VHEE facility.A method for calculating the parameters of single cell from the field distribution was introduced to simplify the design of the BTW ***-domain circuit equations were applied to calculate the transient beam parameters of the buncher in the unsteady state.A prototype of the BTW structure with a thermionic cathode-diode electron gun was designed,fabricated,and tested at high power at the Tsinghua X-band high-power test *** structure successfully operated with 5-MW microwave pulses from the pulse compressor and outputted electron bunches with an energy of 8 MeV and a pulsed current of 108 mA.

关键词： Backward traveling-wave accelerating structure Equivalent circuit model High-power test Very high-energy electron radiotherapy

Towards full-stack deep learning-empowered data processing pipeline for synchrotron tomography experiments

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The Innovation 2024年第1期5卷 127-138页

作者： Zhen Zhang Chun Li Wenhui Wang Zheng Dong Gongfa Liu Yuhui Dong Yi Zhang National Synchrotron radiation Laboratory University of Science and Technology of ChinaHefei 230029China Beijing Synchrotron radiation Facility Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China

Synchrotron tomography experiments are transitioning into multifunctional,cross-scale,and dynamic characterizations,enabled by new-generation synchrotron light sources and fast developments in beamline ***,with the spatial and temporal resolving power entering a new era,this transition generates vast amounts of data,which imposes a significant burden on the data processing ***,as a highly accurate and efficient data processing method,deep learning shows great potential to address the big data challenge being encountered at future synchrotron *** this review,we discuss recent advances employing deep learning at different stages of the synchrotron tomography data processing *** also highlight how applications in other data-intensive fields,such as medical imaging and electron tomography,can be migrated to synchrotron ***,we provide our thoughts on possible challenges and opportunities as well as the outlook,envisioning selected deep learning methods,curated big models,and customized learning strategies,all through an intelligent scheduling solution.

关键词： processing pipeline outlook

Two-dimensional particle-in-cell modeling of blow-off impulse by X-ray irradiation

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Nuclear Science and Techniques 2024年第3期35卷 53-69页

作者： Ruibo Li Jin-Long Jiao Hui Luo Dezhi Zhang Dengwang Wang Kai Wang Graduate School of China Academy of Engineering physics Beijing 100193China Zhejiang Institute of Modern physics Institute of AstronomySchool of PhysicsZhejiang UniversityHangzhou 310027China National Key Laboratory of Intense Pulsed radiation Simulation and Effect Northwest Institute of Nuclear TechnologyXi’an 710024China

Space objects such as spacecraft or missiles may be exposed to intense X-rays in outer space,leading to severe *** reinforcement of these objects to reduce the damage caused by X-ray irradiation is a significant *** blow-off impulse(BOI)is a crucial physical quantity for investigating material damage induced by X-ray ***,the accurate calculation of BOI is challenging,particularly for large deformations of materials with complex *** this study,we develop a novel two-dimensional particle-in-cell code,Xablation2D,to calculate BOIs under far-field X-ray *** significantly reduces the dependence of the numerical simulation on the grid *** reliability of this code is verified by simulation results from open-source codes,and the calculated BOIs are consistent with the experimental and analytical results.

关键词： X-ray irradiation Energy deposition Blow-off impulse Particle in cells

Isoscaling properties for neutron-rich fragments in highly asymmetric heavy ion collision systems

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Chinese physics C 2024年第6期48卷 136-144页

作者：彭丹马春旺乔春源刘星泉魏慧玲 Institute of Particle and Nuclear physics College of PhysicsHenan Normal UniversityXinxiang 453007China Institute of Nuclear Science and Technology Henan Academy of SciencesZhengzhou 450046China Key Laboratory of radiation physics and Technology of the Ministry of Education Sichuan UniversityChengdu 610064China

Traditionally,isoscaling has been interpreted and applied within the framework of the grand canonical ensemble,based on the assumption that fragment production occurs following the attainment of a statistical equilibrium ***,the influence of the symmetry energy can lead to differences in the neutron and density distribution in neutron-rich *** in turn may impact the iso scaling parameters(usually denoted byαandβ).We examine the isoscaling properties for neutron-rich fragments produced in highly asymmetric systems on inverse kinematics,namely^(40,48)Ca and ^(58,64)Ni+^(9)Be at 140 MeV per *** evaluate α and β values and sort them as a function of the neutron excess I≡*** significant differences in a extracted from fragments within different ranges of I emphasize the importance of understanding the dependence of isoscaling parameters on fragments generated in various collision ***,the|β(N)|/α(Z)value for a specific fragment in small size and highly iso spin asymmetry systems can serve as a probe to detect the variations in neutron density and proton density in different regions of the nucleus and indicate the limitations of theoretical models in investigating these issues.

关键词： isoscaling symmetry energy nuclear density neutron-rich fragment heavy ion collision

Mismatch analysis of all-fiber coherent beam combiners based on the self-imaging effect

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High Power Laser Science and Engineering 2024年第2期12卷 1-15页

作者： Yuefang Yan Yu Liu Haoyu Zhang Yuwei Li Chao Guo Qiang Shu Wenhui Huang Feng Jing Rumao Tao Laser Fusion Research Center China Academy of Engineering PhysicsMianyangChina Key Laboratory of Particle&radiation Imaging(Tsinghua University) Ministry of EducationBeijingChina

All-fiber coherent beam combiners based on the self-imaging effect can achieve a near-perfect single laser beam,which can provide a promising way to overcome the power limitation of a single-fiber *** of the key points is combining efficiency,which is determined by various mismatches during fabrication.A theoretical model has been built,and the mismatch error is analyzed numerically for the first *** mismatch errors have been numerically studied with the beam quality and combining efficiency being chosen as the evaluation *** tolerance of each mismatch error for causing 1%loss is calculated to guide the design of the beam *** simulation results are consistent with the experimental results,which show that the mismatch error of the square-core fiber is the main cause of the efficiency *** results can provide useful guidance for the fabrication of all-fiber coherent beam combiners.

关键词： all-fiber coherent beam combination mismatch analysis self-imaging

Five-view three-dimensional reconstructionfor ultrafast dynamic imaging of pulsedradiation sources

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Matter and radiation at Extremes 2024年第2期9卷 63-73页

作者： Jianpeng Gao Liang Sheng Xinyi Wang Yanhong Zhang Liang Li Baojun Duan Mei Zhang Yang Li Dongwei Hei Department of Engineering physics Tsinghua UniversityBeijing 100084China National Key Laboratory of Intense Pulsed radiation Simulation and Effect Northwest Institute of Nuclear TechnologyXi’an 710024China

Multiaxial neutron/x-ray imaging and three-dimensional (3D) reconstruction techniques play a crucial role in gaining valuable insights intothe generation and evolution mechanisms of pulsed radiation sources. Owing to the short emission time (∼200 ns) and drastic changes of thepulsed radiation source, it is necessary to acquire projection data within a few nanoseconds in order to achieve clear computed tomography3D imaging. As a consequence, projection data that can be used for computed tomography image reconstruction at a certain moment are oftenavailable for only a few angles. Traditional algorithms employed in the process of reconstructing 3D images with extremely incomplete datamay introduce significant distortions and artifacts into the final image. In this paper, we propose an iterative image reconstruction methodusing cylindrical harmonic decomposition and a self-supervised denoising network algorithm based on the deep image prior method. Weaugment the prior information with a 2D total variation prior and a 3D deep image prior. Single-wire Z-pinch imaging experiments have beencarried out at Qin-1 facility in five views and four frames, with a time resolution of 3 ns for each frame and a time interval of 40 ns betweenadjacent frames. Both numerical simulations and experiments verify that our proposed algorithm can achieve high-quality reconstructionresults and obtain the 3D intensity distribution and evolution of extreme ultraviolet and soft x-ray emission from plasma.

关键词： frames image sources