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Cross section measurement for the^(232)Th(n,f)reaction in the 4.50−5.40 MeV region using a time projection chamber

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Chinese physics C 2024年第10期48卷 157-167页

作者： Haofan Bai Han Yi Yankun Sun Yiwei Hu Jie Liu Zepeng Wu Cong Xia Wenkai Ren Wentian Cao Tieshuan Fan Guohui Zhang Ruirui Fan Yang Li Wei Jiang Yonghao Chen You Lv Changjun Ning Weihua Jia Zhiyong Zhang Haolei Chen Zhen Chen Maoyuan Zhao Changqing Feng Shubin Liu State Key Laboratory of Nuclear physics and Technology Institute of Heavy Ion PhysicsPeking UniversityBeijing 100871China Institute of High Energy physics Chinese Academy of SciencesBeijing 100049China Spallation Neutron Source Science Center Dongguan 523803China National Key Laboratory of Intense Pulsed radiation Simulation and Effect Northwest Institute of Nuclear TechnologyXi'an 710024China Department of Nuclear Science and Technology School of Energy and Power EngineeringXi’an Jiaotong UniversityXi’an 710049China State Key Laboratory of Particle Detection and Electronics University of Science and Technology of ChinaHefei 230026China Department of Modern physics University of Science and Technology of ChinaHefei 230026China

Accurate cross sections of neutron induced fission reactions are required in the design of advanced nuclear systems and the development of fission *** projection chambers(TPCs),with their track reconstruction and particle identification capabilities,are considered the best detectors for high-precision fission cross section *** TPC developed by the back-streaming white neutron source(Back-n)team of the China Spallation Neutron Source(CSNS)was used as the fission fragment detector in *** this study,the cross sections of the ^(232)Th(n,f)reaction at five neutron energies in the 4.50−5.40 MeV region were *** fission fragments and α particles were well identified using our TPC,which led to a higher detection efficiency of the fission fragments and smaller uncertainty of the measured cross *** is the first measurement of the ^(232)Th(n,f)reaction using a TPC for the detection of fission *** uncertainties less than 5%,our cross sections are consistent with the data in different evaluation libraries,including JENDL-4.0,ROSFOND-2010,CENDL-3.2,ENDF/B-VⅢ.0,and BROND-3.1,whose uncertainties can be reduced after future improvement of the measurement.

关键词： ^(232)Th(n,f)fission cross section time projection chamber(TPC) ^(232)Th

Annealing-induced gradient nanostructured FeCrAlTiMo high-entropy alloy coatings with significantly enhanced wear resistance

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Tungsten 2024年第3期6卷 544-548页

作者： Jian Yang Ming-Yang Zhou Ji-Jun Yang Key Laboratory of radiation physics and Technology of Ministry of Education Institute of Nuclear Science and Technology Sichuan University Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China

Recently, the amorphous high-entropy alloy(HEA) coatings exhibit an impressive resistance to the lead–bismuth eutectic(LBE) corrosion and ion irradiation, showing great application potential for lead-cooled fast reac...

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Lead-free metal halide scintillator materials for imaging applications

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Science China(Information Sciences) 2024年第8期67卷 85-101页

作者： Junzhe LIN Dan GUO Tianrui ZHAI Department of physics and Optoelectronic Engineering Beijing University of Technology

High-energy radiation detection and imaging technology has significant applications in highenergy physics research, medical imaging, and industrial monitoring. Lead-free metal halides exhibit exceptional potential for conducting indirect detection of high-energy radiation due to their characteristics of low toxicity, strong stability, high light yield, and large Stokes shift. This paper reviews the most recent advances in lead-free metal halide scintillator materials for X-ray imaging. Subsequently, it lists the most important parameters of scintillator performance and introduces the production procedures for single crystal, powder,and nanocrystal scintillators. Furthermore, it discusses the manufacturing of scintillator films with improved performance, focusing on large-area flexible scintillator films and the coupling with microstructures. Finally,it discusses current challenges and opportunities for enhancing X-ray imaging using lead-free metal halide scintillator materials.

关键词： lead-free metal halide scintillators imaging film luminescence

A deep learning interatomic potential suitable for simulating radiation damage in bulk tungsten

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Tungsten 2024年第2期6卷 304-322页

作者： Chang-Jie Ding Ya-Wei Lei Xiao-Yang Wang Xiao-Lin Li Xiang-Yan Li Yan-Ge Zhang Yi-Chun Xu Chang-Song Liu Xue-Bang Wu Key Laboratory of Materials physics Institute of Solid State PhysicsHFIPSChinese Academy of SciencesHefei 230031China Science Island University of Science and Technology of ChinaHefei 230026China Laboratory of Computational physics Institute of Applied Physics and Computational MathematicsBeijing 100088China

So far, it has been a challenge for existing interatomic potentials to accurately describe a wide range of physical properties and maintain reasonable efficiency. In this work, we develop an interatomic potential for simulating radiation damage in body-centered cubic tungsten by employing deep potential, a neural network-based deep learning model for representing the potential energy surface. The resulting potential predicts a variety of physical properties consistent with first-principles calculations, including phonon spectrum, thermal expansion, generalized stacking fault energies, energetics of free surfaces, point defects, vacancy clusters, and prismatic dislocation loops. Specifically, we investigated the elasticity-related properties of prismatic dislocation loops, i.e., their dipole tensors, relaxation volumes, and elastic interaction energies. This potential is found to predict the maximal elastic interaction energy between two 1/2 loops better than previous potentials, with a relative error of only 7.6%. The predicted threshold displacement energies are in reasonable agreement with experimental results, with an average of 128 eV. The efficiency of the present potential is also comparable to the tabulated gaussian approximation potentials and modified embedded atom method potentials, meanwhile, can be further accelerated by graphical processing units. Extensive benchmark tests indicate that this potential has a relatively good balance between accuracy, transferability, and efficiency.

关键词： Machine learning Deep learning Interatomic potential radiation damage Tungsten

Finely regulated luminescent Ag-In-Ga-S quantum dots with green-red dual emission toward white light-emitting diodes

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Opto-Electronic Advances 2024年第9期7卷 54-63页

作者： Zhi Wu Leimeng Xu Jindi Wang Jizhong Song Key Laboratory of Materials physics of Ministry of Education Laboratory of Zhongyuan LightSchool of PhysicsZhengzhou UniversityDaxue Road 75Zhengzhou 450052China

Ag-In-Ga-S(AIGS)quantum dots(QDs)have recently attracted great interests due to the outstanding optical properties and eco-friendly components,which are considered as an alternative replacement for toxic Pb-and Cd-based ***,enormous attention has been paid to how to narrow their broadband spectra,ignoring the application advantages of the broadband *** this work,the AIGS QDs with controllable broad green-red dual-emission are first reported,which is achieved through adjusting the size distribution of QDs by controlling the nucleation and growth of AIGS ***,the AIGS QDs exhibit broad dual-emission at green-and red-band evidenced by photoluminescence(PL)spectra,and the PL relative intensity and peak position can be finely ***,the dual-emission is the intrinsic characteristics from the difference in confinement effect of large particles and tiny particles confirmed by temperature-dependent PL ***,the AIGS QDs(the size consists of 17 nm and 3.7 nm)with 530 nm and 630 nm emission could successfully be synthesized at 220°*** combining the blue light-emitting diode(LED)chips and dual-emission AIGS QDs,the constructed white light-emitting devices(WLEDs)exhibit a continuous and broad spectrum like natural sunlight with the Commission Internationale de l’Eclairage(CIE)chromaticity coordinates of(0.33,0.31),a correlated color temperature(CCT)of 5425 K,color rendering index(CRI)of 90,and luminous efficacy of radiation(LER)of 129 lm/W,which indicates that the AIGS QDs have huge potential for lighting applications.

关键词： quantum dots Ag-In-Ga-S dual emission white light-emitting diodes

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核物质中张量力效应的相对论第一性原理研究

Science Bulletin 2024年第14期69卷 2166-2169页

作者：王锶博童辉王宸璨赵强 Peter Ring 孟杰 Department of physics and Chongqing Key Laboratory for Strongly Coupled physics Chongqing UniversityChongqing 401331China Helmholtz Institute for radiation and Nuclear physics University of BonnBonn D-53115Germany School of physics and Astronomy Sun Yat-sen UniversityZhuhai 519082China Center for Exotic Nuclear Studies Institute for Basic ScienceDaejeon 34126South Korea Department of physics Technical University of MunichGarching D-85747Germany State Key Laboratory of Nuclear physics and Technology School of PhysicsPeking UniversityBeijing 100871China

As a crucial ingredient of the nucleon-nucleon(NN)interaction,the tensor force has an important impact on the structural and dynamical properties of the nuclear many-body system,particularly the properties of exotic nuclei far away from the stability,which are crucial for understanding the nucleosynthesis in nuclear *** efforts have been devoted to studying the influence of the tensor force in the effective NN interaction in the nuclear medium within the configuration interaction shell model[1]and the density functional theories(DFTs)[2].Due to the difference of modeling the effective NN interaction and the difficulty of determining the tensor-force strengths in finite nuclei,the tensorforce effects in nuclear physics still need to be fully settled.

关键词：张量力核物质 tensor

Cone-beam computed tomography noise reduction method based on U-Net with convolutional block attention module in proton therapy

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Nuclear Science and Techniques 2024年第7期35卷 89-100页

作者： Xing-Yue Ruan Xiu-Fang Li Meng-Ya Guo Mei Chen Ming Lv Rui Li Zhi-Ling Chen Shanghai Institute of Applied physics Chinese Academy of SciencesShanghai201800China University of Chinese Academy of Sciences Beijing100049China Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai201210China Department of radiation Oncology Ruijin HospitalShanghai Jiao Tong University School of MedicineShanghai200025China Shanghai Key Laboratory of Proton therapy Shanghai201801China

Cone-beam computed tomography(CBCT) is mostly used for position verification during the treatment process. However,severe image artifacts in CBCT hinder its direct use in dose calculation and adaptive radiation therapy re-planning for proton therapy. In this study, an improved U-Net neural network named CBAM-U-Net was proposed for CBCT noise reduction in proton therapy, which is a CBCT denoised U-Net network with convolutional block attention modules. The datasets contained 20 groups of head and neck images. The CT images were registered to CBCT images as ground truth. The original CBCT denoised U-Net network, sCTU-Net, was trained for model performance comparison. The synthetic CT(SCT) images generated by CBAM-U-Net and the original sCTU-Net are called CBAM-SCT and U-Net-SCT images, respectively. The HU accuracies of the CT, CBCT, and SCT images were compared using four metrics: mean absolute error(MAE), root mean square error(RMSE), peak signal-to-noise ratio(PSNR), and structure similarity index measure(SSIM). The mean values of the MAE, RMSE, PSNR, and SSIM of CBAM-SCT images were 23.80 HU, 64.63 HU, 52.27 dB, and 0.9919, respectively,which were superior to those of the U-Net-SCT images. To evaluate dosimetric accuracy, the range accuracy was compared for a single-energy proton beam. The γ-index pass rates of a 4 cm × 4 cm scanned field and simple plan were calculated to compare the effects of the noise reduction capabilities of the original U-Net and CBAM-U-Net on the dose calculation results. CBAM-U-Net reduced noise more effectively than sCTU-Net, particularly in high-density tissues. We proposed a CBAM-U-Net model for CBCT noise reduction in proton therapy. Owing to the excellent noise reduction capabilities of CBAM-U-Net, the proposed model provided relatively explicit information regarding patient tissues. Moreover, it maybe be used in dose calculation and adaptive treatment planning in the future.

关键词： Proton therapy Cone-beam CT CBAM-U-Net γ-index

Experimental observation of Fermi-level flat band in novel kagome metal CeNi_(5)

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Chinese physics B 2024年第8期33卷 467-472页

作者：陈学智王乐张帅张任杰程以伟胡裕栋孟承诺刘正太吕佰晴黄耀波 Shanghai Institute of Applied physics Chinese Academy of SciencesShanghai 201800China Tsung-Dao Lee Institute Shanghai Jiao Tong UniversityShanghai 200240China University of Chinese Academy of Sciences Beijing 100049China Shenzhen Institute for Quantum Science and Engineering Southern University of Science and TechnologyShenzhen 518055China International Quantum Academy Shenzhen 518048China Institute of Theoretical physics Chinese Academy of SciencesBeijing 100190China Beijing National Laboratory for Condensed Matter physics and Institute of physics Chinese Academy of SciencesBeijing 100190China School of physics and Astronomy Shanghai Jiao Tong UniversityShanghai 200240China Zhangjiang Institute for Advanced Study Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Synchrotron radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China

Kagome materials are a class of material with a lattice structure composed of corner-sharing triangles that produce various exotic electronic phenomena,such as Dirac fermions,van Hove singularities,and flat ***,most of the known kagome materials have a flat band detached from the Fermi energy,which limits the investigation of the emergent flat band *** this work,by combining soft x-ray angle-resolved photoemission spectroscopy(ARPES)and the first-principles calculations,the electronic structure is investigated of a novel kagome metal CeNi_(5) with a clear dispersion along the kz direction and a Fermi level flat band in theΓ–K–M–Γ***,resonant ARPES experimental results indicate that the valence state of Ce ions is close to 4^(+),which is consistent with the transport measurement *** results demonstrate the unique electronic properties of CeNi_(5) as a new kagome metal and provide an ideal platform for exploring the flat band physics and the interactions between different types of flat bands by tuning the valence state of Ce ions.

关键词： ARPES kagome lattice band structure flat band

Possibilities for the synthesis of superheavy element Z=121 in fusion reactions

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Nuclear Science and Techniques 2024年第6期35卷 90-100页

作者： Ming-Hao Zhang Yu-Hai Zhang Ying Zou Xiu-Xiu Yang Gen Zhang Feng-Shou Zhang The Key Laboratory of Beam Technology of Ministry of Education College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China Institute of radiation Technology Beijing Academy of Science and TechnologyBeijing 100875China School of Physical Science and Technology Guangxi UniversityNanning 530004China National Laboratory of Heavy Ion Accelerator of Lanzhou Center of Theoretical Nuclear PhysicsLanzhou 730000China

Based on the dinuclear system model,the calculated evaporation residue cross sections matched well with the current experimental *** synthesis of superheavy elements Z=121 was systematically studied through combinations of stable projectiles with Z=21-30 and targets with half-lives exceeding 50 *** influence of mass asymmetry and isotopic dependence on the projectile and target nuclei was investigated in *** reactions^(254)Es(^(46)Ti,3n)^(297)121 and^(252)Es(^(46)Ti,3n)^(295)121 were found to be experimentally feasible for synthesizing superheavy element Z=121,with maximal evaporation residue cross sections of 6.619 and 4.123 fb at 219.9 and 223.9 MeV,respectively.

关键词： Superheavy nuclei Dinuclear system model Fusion reaction Evaporation residue cross section