Physics design of 14 MeV neutron generator facility at the Institute for Plasma Research

A high energy and high yield neutron source is a prime requirement for technological studies related to fusion reactor development. It provides a high-energy neutron environment for small-scale fusion reactor components research and testing such as tritium breeding, shielding, plasmafacing materials, reaction cross-section data study for fusion materials, etc. Along with ITER participation, the Institute of Plasma Research, India is developing an accelerator-based 14 MeV neutron source with a yield of 10^(12)n s^(-1). The design of the source is based on the deuterium–tritium fusion reaction. The deuterium beam is accelerated and delivered to the tritium target to generate 14 MeV neutrons. The deuterium beam energy and tritium availability in the tritium target are the base parameters of the accelerator-based neutron source design. The paper gives the physics design of the neutron generator facility of the Institute for Plasma Research. It covers the requirements, design basis, and physics parameters of the neutron generator. As per the analytical results generator can produce more than 1 × 10^(12)n s^(-1)with a 110 keV D^(+) ion beam of 10 mA and a minimum 5 Ci tritium target. However, the detailed simulation with the more realistic conditions of deuteron ion interaction with the tritium titanium target shows that the desired results cannot be achieved with 110 keV. The safe limit of the ion energy should be 300 keV as per the simulation. At 300 keV ion energy and 20 mA current, it reaches 1.6 × 10^(12)n s^(-1). Moreover, it was found that to ensure sufficiently long operation time a tritium target of more than 20 Ci should be used. The scope of the neutron source is not limited to the fusion reactor research studies, it is extended to other areas such as medical radioisotopes research, semiconductor devices irradiations, and many more.

Selected topics of quantum computing for nuclear physics

Nuclear physics,whose underling theory is described by quantum gauge field coupled with matter,is fundamentally important and yet is formidably challenge for simulation with classical computers.Quantum computing provides a perhaps transformative approach for studying and understanding nuclear physics.With rapid scaling-up of quantum processors as well as advances on quantum algorithms,the digital quantum simulation approach for simulating quantum gauge fields and nuclear physics has gained lots of attention.In this review,we aim to summarize recent efforts on solving nuclear physics with quantum computers.We first discuss a formulation of nuclear physics in the language of quantum computing.In particular,we review how quantum gauge fields(both Abelian and non-Abelian)and their coupling to matter field can be mapped and studied on a quantum computer.We then introduce related quantum algorithms for solving static properties and real-time evolution for quantum systems,and show their applications for a broad range of problems in nuclear physics,including simulation of lattice gauge field,solving nucleon and nuclear structures,quantum advantage for simulating scattering in quantum field theory,non-equilibrium dynamics,and so on.Finally,a short outlook on future work is given.

Nucleus++:a new tool bridging AME and NuBAsE for advancing nuclear data analysis

The newly developed software,Nucleus++,is an advanced tool for displaying basic nuclear physics properties from NubAsE and integrating comprehensive mass information for each nuclide from Atomic Mass Evaluation.Additionally,it allows users to compare experimental nuclear masses with predictions from different mass models.Building on the success and learning experiences of its predecessor,Nucleus,this enhanced tool introduces improved functionality and compatibility.With its user-friendly interface,Nucleus++was designed as a valuable tool for scholars and practitioners in the field of nuclear science.This article offers an in-depth description of Nucleus++,highlighting its main features and anticipated impacts on nuclear science research.

MY WORK IN THE FIELD OF NUCLEAR PHYSICS

After graduating from the physics department of Qinghua University in 1952, I started working in the development of nuclear detectors (including cloud chambers and scintillometers) under the instruction of Profs. Yang Chengzhong and Dai Chuanzeng at the CAS Institute of Modern Physics.From 1956 to 1958,I studied at Lebedev’s Institute of Physics under the Soviet Academy

Calibration of CR-39 solid-state track detectors for study of laser-driven nuclear reactions

It is of particular interest to investigate nuclear fusion reactions generated by high-intensity lasers in plasma environments that are similar to real astrophysical conditions.We have experimentally investigated2H(d,p)3H,one of the most crucial reactions in big bang nucleosynthesis models,at the Shenguang-Ⅱlaser facility.In this work,we present a new calibration of CR-39 solidstate track detectors,which are widely employed as the main diagnostics in this type of fusion reaction experiment.We measure the dependence of the track diameter on the proton energy.It is found that the track diameters of protons with different energies are likely to be identical.We propose that in this case,the energy of the reaction products can be obtained by considering both the diameters and gray levels of these tracks.The present results would be very helpful for analyzing the2 H(d,p)3H reaction products recorded with the same batch of CR-39 solid-state track detectors.

An online physical simulation method for enhanced oil recovery by air injection in shale oil

In order to understand the mechanism of air flooding shale oil, an online physical simulation method for enhanced shale oil recovery by air injection was established by integrating CT scanning and nuclear magnetic resonance(NMR). The development effect of shale oil by air flooding under different depletion pressures, the micro-production characteristics of pore throats with different sizes and the mechanism of shale oil recovery by air flooding were analyzed. The effects of air oxygen content, permeability, gas injection pressure, and fractures on the air flooding effect in shale and crude oil production in pores with different sizes were analyzed. The recovery of shale oil can be greatly improved by injecting air into the depleted shale reservoir, but the oil displacement efficiency and the production degree of different levels of pore throats vary with the injection timing. The higher the air oxygen content and the stronger the low-temperature oxidation, the higher the production degree of pores with different sizes and the higher the shale oil recovery. The higher the permeability and the better the pore throat connectivity, the stronger the fluid flow capacity and the higher the shale oil recovery. As the injection pressure increases, the lower limit of the production degree of pore throats decreases, but gas channeling may occur to cause a premature breakthrough;as a result, the recovery increases and then decreases. Fractures can effectively increase the contact area between gas and crude oil, and increase the air sweep coefficient and matrix oil drainage area by supplying oil to fractures through the matrix, which means that a proper fracturing before air injection can help to improve the oil displacement effect under a reasonable production pressure difference.

Spatial and spectral measurement of laser-driven protons through radioactivation

The simultaneous measurement of the spatial profile and spectrum of laser-accelerated protons is important for further optimization of the beam qualities and applications.We report a detailed study regarding the underlying physics and regular procedure of such a measurement through the radioactivation of a stack composed of aluminum,copper,and CR-39 plates as well as radiochromic films(RCFs).After being radioactivated,the copper plates are placed on imaging plates(IPs)to detect the positrons emitted by the reaction products through contact imaging.The spectrum and energy-dependent spatial profile of the protons are then obtained from the IPs and confirmed by the measured ones from the RCFs and CR-39 plates.We also discuss the detection range,influence of electrons,radiation safety,and spatial resolution of this measurement.Finally,insights regarding the extension of the current method to online measurements and dynamic proton imaging are also provided.

The Nuclear Clock Correction for Universal Gravitation

Science is losing some fixed references shifting from universality to relativity: time and space become space time, the meter is related to the velocity of light and the second is fixed by the ticketing of a Cesium atom. In the case of Gravity, Nature was so friendly to Newton to allow him the writing of the Universal Gravitational Law, that changed the view of the Universe for the last three centuries. However, the way matter generates Gravity was unknown to Newton and the problem is still nowadays ignored by most scientists and remains the ultimate question mark of physics. We paid attention to the ticketing of all existing nuclides and found that the parameters of the neutronproton transformations are so precise, in describing these reactions, that can be considered universal constants. Instead, the emitted neutrino flux Fo is almost constant with a mean value of 6.668E20 neutrino per gram and second over the wide range of all nuclides with some deviation for lighter nuclei. This is the reason why Newton was able to find his Universal Gravitational Law and allows us today to state a relation of this flux with the Gauss constant G on the basis of nuclear properties. Moreover, it explains the mechanism that bodies use for their mutual attraction with a simplification of the three-body problem in celestial bodies computation. We have to remember that Newton model, with a fixed gravitational Gauss constant G, or the equivalent with a fixed neutrino flux Fo, have been used for the determination of the mass of the celestial bodies in motion with the implicit assumption that the gravitational and inertial mass are the same. In this paper we recognize the big difference in composition of the Sun and the gaseous planets compared to the terrestrial ones and show how the relatively small difference of the neutrino flux can change our vision of the Universe.

中国原子能科学研究院核物理基础研究最新进展与展望

核物理是物质科学研究的基础研究前沿和重大应用领域之一,对人类探索物质结构的微观层次、国家的地位与安全发挥了重大作用。中国原子能科学研究院(简称原子能院)核物理基础研究团队依托北京放射性核束装置、HI-13串列加速器、锦屏深地核天体物理加速器等实验设施,开展了核物理基础相关实验与理论研究,在质子晕核破裂机制、不稳定核衰变新模式、核天体反应深地高精度测量、激光驱动核反应等方面取得了多项创新研究成果。本文评述了“十四五”期间原子能院在核物理基础研究方面取得的一些最新进展,并展望了原子能院未来在核物理大科学装置、特色中小型装置、核理论、新型实验技术、学科交叉融合等方面的发展思路。

复合助剂对低温喷雾干燥蓝靛果粉理化性质的影响

为保证低温喷雾干燥后蓝靛果粉品质,采用黄金分割法研究复合助剂(麦芽糊精、β-环糊精和乳清蛋白)对喷雾干燥蓝靛果粉理化性质的影响,分析低温进风温度(50~90℃)对蓝靛果粉花青素保留率、集粉率和含水率的影响规律。结果表明,在麦芽糊精、β-环糊精的质量比例为85.4%、14.6%时,集粉率高达37.96%;随进料溶液中麦芽糊精质量比例增加,蓝靛果粉玻璃化转变温度、水溶性指数、堆积密度、亮度L^(*)值、红度a^(*)值和色差值ΔE呈增加趋势,含水率、花青素含量和黄度b^(*)值呈下降趋势;在麦芽糊精、β-环糊精和乳清蛋白质量比例为72.9%、12.5%、14.6%时,集粉率达到最高(40.11%);随料液中乳清蛋白质量比例增加,蓝靛果粉含水率、花青素含量呈上升趋势,其玻璃化转变温度、水溶性指数、亮度L^(*)值、红度a^(*)值、黄度b^(*)值和色差值ΔE等指标呈下降趋势;复合助剂显著提高蓝靛果粉集粉率(P<0.05),对其中的花青素起到较强保护作用,其含水率、水溶性指数、堆积密度等理化指标均接近于最优水平。低温喷雾干燥研究发现,随进风温度上升,集粉率和含水率呈负相关,在进风温度90℃时,集粉率最高的配方中可实现较高花青素保留率(89.94%)。低频核磁共振波谱以及质子密度图像信息分析表明,加入的助剂与蓝靛果果汁中水分通过氢键、静电结合力和疏水作用等分子间作用力,形成稳定性高水合物、增强液滴聚结抵抗力,提高料液玻璃态转换温度,从而实现高集粉率和高花青素保留率的蓝靛果果粉低温喷雾干燥;红外光谱分析表明,复合助剂可在蓝靛果果粉中形成分子间氢键,并对花青素等活性物质进行固定包埋保护。研究结果可为蓝靛果粉喷雾干燥加工生产提供理论支撑和参考依据。

苏联氢弹研制科学理论基础的奠定——核聚变理论工作(1946—1953)

1946—1953年间,苏联4个科研团队的核聚变理论工作,既是苏联氢弹研制的首要工作,也是苏联核计划的重要组成部分,为氢弹研制奠定了科学理论基础。库尔恰托夫团队负责分析情报信息并向政府提供建议,对其他小组的工作进行管理并开展了少许的理论研究工作;泽利多维奇小组是苏联最早对轻核聚变可行性进行研究的团队,开展了与“管式构型”氢弹相关的核聚变理论工作;朗道小组从工作伊始就探索核聚变理论的实际应用问题,就两种构型的氢弹开展了重要的理论计算工作;塔姆小组提出并完善了“层式构型”氢弹的设计构想,并开展了与此相关的核聚变理论工作,在苏联首枚氢弹的研制中发挥了关键作用。他们开展的核聚变理论工作为苏联氢弹研制的设计理论、技术理论等理论问题提供了科学依据,在热核装药的选择、引爆问题、爆炸过程、能量释放以及试爆工作等实际问题的解决中起到了极其重要的理论指导作用。核聚变理论工作不仅为苏联氢弹研制的成功提供了理论保障,而且在某种程度上还加深了核裂变理论的相关研究,进而构建并强化了苏联核武体系的科学理论基础,而且还进一步改进了对原子弹、氢弹的研发工作,大大增强了苏联的国防力量。

重离子加速器中的原子核碰撞虚拟仿真实验的建设与应用

利用虚拟仿真技术,结合教学团队的科研成果,设计开发了重离子加速器中的原子核碰撞等一系列实验教学项目.这些实验项目能够在电脑上再现真实的实验场景,解除了实验场地、费用、防护等方面的限制,为培养学生的实验探究设计能力、开拓学生视野提供了重要支撑.结合虚拟仿真技术的特点,教师团队采用适应的教学方法进行授课,建立了完善的评价体系.经过3年的课程建设,该课程在学生培养、教师教学质量、推广应用方面取得了良好的效果.

一体化快堆全锕系核素循环的物理可行性分析

一体化快堆是一体化闭式循环快堆核能系统的简称,由钠冷快堆、金属燃料制造设施、乏燃料处理设施和废物整备设施组成,是快堆及其燃料循环系统的高级发展阶段,能够实现铀资源的高效利用和废物最小化,显著提升闭式核燃料循环的质量和效率。一体化快堆的最主要特征是核燃料的快速循环和多次循环,且核燃料的组成包括铀、钚和次锕系核素,可以称为全锕系核素循环。本文从反应堆核设计、燃料制造燃料成分控制方法、乏燃料处理回收率要求、燃料循环过程中物料辐射特性等方面,分析评估了一体化快堆全锕系核素循环的物理可行性。

基质裂缝耦合下的致密油/页岩油动态渗流实验

基于核磁共振和CT扫描技术建立了动态驱渗结合的物理模拟实验方法,分析了致密油/页岩油动态渗吸微观孔喉动用机制及影响动态渗吸开发效果的因素,模拟了致密油/页岩油压裂—焖井—返排—开采一体化的动态渗流过程,明确了不同开发阶段的生产动态特征及对采出程度的贡献。研究表明:致密油/页岩油储层的渗流可分为大孔隙与裂缝间驱替快速产出的强驱替弱渗吸、小孔隙逆向渗吸缓慢采出的弱驱替强渗吸、动态平衡时的弱驱替弱渗吸3个阶段。驱替压力越大,驱替采出程度越高,渗吸采出程度越低,但驱替压力过大注入水易突破前缘,降低采出程度。渗透率越高,渗吸、驱替采出程度越大,渗吸平衡时间越短,最终采出率越高。裂缝可有效加大基质与水的渗吸接触面积,降低油水渗流阻力,促进基质、裂缝间的油水置换,提高基质排油速度和采收率。压裂后进行焖井有利于流体的渗吸置换与增能蓄能,有效利用返排液的携带、开采阶段的排驱置换作用是提高采收率的关键。

Reactor field reconstruction from sparse and movable sensors using Voronoi tessellation-assisted convolutional neural networks

The aging of operational reactors leads to increased mechanical vibrations in the reactor interior.The vibration of the incore sensors near their nominal locations is a new problem for neutronic field reconstruction.Current field-reconstruction methods fail to handle spatially moving sensors.In this study,we propose a Voronoi tessellation technique in combination with convolutional neural networks to handle this challenge.Observations from movable in-core sensors were projected onto the same global field structure using Voronoi tessellation,holding the magnitude and location information of the sensors.General convolutional neural networks were used to learn maps from observations to the global field.The proposed method reconstructed multi-physics fields(including fast flux,thermal flux,and power rate)using observations from a single field(such as thermal flux).Numerical tests based on the IAEA benchmark demonstrated the potential of the proposed method in practical engineering applications,particularly within an amplitude of 5 cm around the nominal locations,which led to average relative errors below 5% and 10% in the L_(2) and L_(∞)norms,respectively.

液态金属冷却快堆堆芯物理分析软件LoongSARAX的验证与确认

NECP-SARAX是西安交通大学核工程计算物理实验室自主开发的先进反应堆中子学分析计算系统。在此基础上,西安交通大学针对液态金属冷却快堆的堆芯物理工程设计与安全审评,定制开发了LoongSARAX。为了实现LoongSARAX的工程应用,规范性、系统性的验证与确认是该过程的重要一环。为此,本文针对LoongSARAX验证与确认研究,在搜集整理国际上关于液态金属冷却快堆物理计算基准题的基础上,建立了其验证与确认矩阵,并将程序分成不同模块,分别进行了模块验证、子系统验证和系统确认,范围涵盖冷却剂为钠和铅的快堆,如JOYO、ZPPR17A等。程序验证与确认表明LoongSARAX程序对于液态金属冷却快堆具有较高的计算精度,同时针对中国实验快堆(CEFR)开展了不确定度量化研究。结果表明,在99%置信度下,有效增殖因数计算结果的不确定度有90%的概率落在[-389 pcm,300 pcm]以内。

放射性去污技术应用特点与发展方向

放射性去污是保障核工业可持续发展的重要技术手段。放射性去污不仅关系到核电站和放射性矿产资源开发等设施运行管理过程的综合成本,还关系到人员安全与社会环境安全,应引起足够重视。在对国内外核设施退役与检修过程常用放射性污染清除技术总结的基础上,分析了物理去污、化学去污、电氧化去污、微生物去污以及熔炼去污技术的使用条件和优缺点,提出了放射性去污的技术痛点与发展方向。

Machine learning in nuclear physics at low and intermediate energies

Machine learning(ML)is becoming a new paradigm for scientific research in various research fields due to its exciting and powerful capability of modeling tools used for big-data processing tasks.In this review,we first briefly introduce the different methodologies used in ML algorithms and techniques.As a snapshot of many applications by ML,some selected applications are presented,especially for low-and intermediate-energy nuclear physics,which include topics on theoretical applications in nuclear structure,nuclear reactions,properties of nuclear matter,and experimental applications in event identification/reconstruction,complex system control,and firmware performance.Finally,we present a summary and outlook on the possible directions of ML use in low-intermediate energy nuclear physics and possible improvements in ML algorithms.

不同类型花生浸种过程物理特性变化及内部水分迁移规律

探究高油酸、高蛋白和普通花生在不同温度(25℃和31℃)和浸泡时间(0、3、6、9、12 h)下的浸种特性,利用低场核磁共振成像技术动态监测种子水分相态和迁移,明确不同类型花生种子浸种过程的物理特性变化和吸水动态,旨在探寻不同类型花生适宜的浸种时间和温度,降低花生萌发时种皮破损率。结果表明,不同温度和浸泡时间处理下,3种类型花生种子的质量增加率、体积增加率、含水率增加率及总信号幅值等与花生浸泡时间和温度呈显著正相关(P<0.05)。高蛋白花生YH9326的蛋白质与高蛋白标准比值(P/P标)最高(1.37),在25℃浸种12 h后质量增加率最高(58.91%),与31℃处理无显著差异;25℃下浸种3、6 h含水率增加率较31℃分别下降22%、6%;2种温度下非结合水信号幅值增加率在浸种12 h显著高于浸种9 h,显示出种子持续吸水状态;与31℃浸种相比,25℃下浸种3 h总水和结合水信号幅值增加率分别提高42%和10.0倍。普通花生HY38的油酸与亚油酸比值(OA/LA)最低(1.30),31℃浸种3、6、9 h后,其体积增加率显著提高,分别较25℃浸种时提高8%、17%、25%;浸种9 h后含水率增加率比25℃提高20%;浸种3、6 h,其结合水信号幅值增加率较25℃分别下降35%和29%,但非结合水信号幅值增加率显著提高99%和55%;在31℃浸种6、9 h,非结合水信号幅值增加率无显著差异。高油酸花生YH37的油酸与亚油酸比值(OA/LA)最高(11.1),在25℃下浸种3 h体积增加率(46.13%)高于YH9326和HY38,相较于31℃浸种3、6 h后,其非结合水信号幅值增加率分别降低13%、9%,结合水信号幅值增加率显著提高3.5倍和1.3倍。在25℃浸种,高油酸花生YH37和高蛋白花生YH9326的非结合水信号幅值增加率虽表现持续吸水到浸种12 h,但在浸种6、9 h无显著差异。高蛋白花生YH9326及高油酸花生YH37适宜在25℃浸种6 h,可完成初始快速吸胀吸水;普通花生种子HY38适宜31℃浸种6 h,基本完成初始快速吸胀吸水。