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Electromagnetic fields in ultra-peripheral relativistic heavy-ion collisions

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Nuclear Science and Techniques 2024年第2期35卷 103-109页

作者： Jie Zhao Jin-Hui Chen Xu-Guang Huang Yu-Gang Ma Key Laboratory of Nuclear Physics and Ion-beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai 200433China Shanghai Research Center for Theoretical Nuclear Physics NSFC and Fudan UniversityShanghai 200438China Physics Department and Center for Particle Physics and Field Theory Fudan UniversityShanghai 200438China

Ultra-peripheral heavy-ion collisions(UPCs)offer unique opportunities to study processes under strong electromagnetic fields.In these collisions,highly charged fast-moving ions carry strong electromagnetic fields that can be effectively treated as photon fluxes.The exchange of photons can induce photonuclear and two-photon interactions and excite ions.This excitation of the ions results in Coulomb dissociation with the emission of photons,neutrons,and other particles.Additionally,the electromagnetic fields generated by the ions can be sufficiently strong to enforce mutual interactions between the two colliding ions.Consequently,the two colliding ions experience an electromagnetic force that pushes them in opposite directions,causing a back-to-back correlation in the emitted neutrons.Using a Monte Carlo simulation,we qualitatively demonstrate that the above electromagnetic effect is large enough to be observed in UPCs,which would provide a clear means to study strong electromagnetic fields and their effects.

关键词： Electromagnetic fields neutrons Ultra-peripheral relativistic heavy-ion collisions(UPC)

neutrons in a nanosecond low-pressure discharge in deuterium

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Matter and Radiation at Extremes 2016年第4期1卷 207-212页

作者： Victor F.Tarasenko Mikhail I.Lomaev Dmitry A.Sorokin Boris A.Nechaev Vladimir N.Padalko Gennady N.Dudkin Laboratory of Optical Radiation of the Institute of High Current Electronics SB RAS Tomsk 634055Russia Physical Technical Institute National Research Tomsk Polytechnic UniversityTomsk 634050Russia National Research Tomsk State University Tomsk 634050Russia

Stable neutron generation with a yield of ~1.2×10^(4) neutrons per pulse was obtained during d(d,n)^(3)He reaction initiated by the high-voltage nanosecond discharge in a gap with a potential tungsten cylinder(anode)and a grounded deuterated zirconium plate(cathode)filled with deuterium at a pressure of ~10^(2) Pa.Estimated duration of the neutron pulse was ~1.5 ns.Less intensive neutron emission was registered without deuterated plate.Splashing of material of the tungsten electrode was observed during the high-voltage nanosecond discharge in the deuterium,hydrogen,helium and argon at pressures of 10^(2)-10^(4) Pa.

关键词： neutrons Deuterium High-voltage nanosecond discharge Low-pressure Thermonuclear reaction

Analysis of displacement damage effects on bipolar transistors irradiated by spallation neutrons

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Chinese Physics B 2019年第6期28卷 372-377页

作者：刘岩陈伟贺朝会苏春垒王晨辉金晓明李俊霖薛院院 School of Nuclear Science and Technology Xi’an Jiaotong UniversityXi’an 710049China State Key Laboratory of Intense Pulsed Radiation Simulation and Effect(Northwest Institute of Nuclear Technology) Xi’an 710024China

Displacement damage induced by neutron irradiation in China Spallation Neutron Source(CSNS) is studied on bipolar transistors with lateral PNP, substrate PNP, and vertical NPN configurations, respectively. Comparison of the effects on different type transistors is conducted based on displacement damage factor, and the differences are analyzed through minority carrier lifetime calculation and structure analysis. The influence of CSNS neutrons irradiation on the lateral PNP transistors is analyzed by the gate-controlled method, including the oxide charge accumulation, surface recombine velocity,and minority carrier lifetime. The results indicate that the total ionizing dose in CSNS neutron radiation environment is negligible in this study. The displacement damage factors based on 1-MeV equivalent neutron flux of different transistors are consistent between Xi’an pulse reactor(XAPR) and CSNS.

关键词： displacement damage China Spallation Neutron Source(CSNS) reactor neutrons bipolar transistors

Regulating the Nuclear Reactor through Changes of the Fraction of Delayed neutrons: Theoretical Probabilities

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Journal of Modern Physics 2010年第6期1卷 379-384页

作者： Dmitry V. Filippov Leonid I. Urutskoev Valery I. Rachkov Olga I. Gadzaova Larion A. Lebedev 不详

In recent years а significant number of both theoretical and experimental works devoted to the influence of external electromagnetic fields and ionization on the probability of beta decays have been published. The present work investigates the feasibility of using this physical effect as the main mechanism for controlling the reactor. In this paper a system of equations is written and studied that allows one to describe the work of a nuclear reactor in the case where the probability of beta decay and, therefore, the fraction of delayed neu-trons is a function of time. It is shown that in the case of a constant fraction of delayed neutrons, the pro-posed system of equations is identical to the known system. As can be seen from analysis of a solution of the new system of equations for the proposed method of reactor control, acceleration by instantaneous neutrons is impossible even theoretically.

关键词： Fraction of Delayed neutrons Bound-State Beta-Decay Kinetic Equation

Generation of high-energy neutrons with the 300-ps-laser system PALS

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High Power Laser Science and Engineering 2014年第3期2卷 72-77页

作者： J.Krsa D.Klír A.Velyhan E.Krousky M.Pfeifer K.Rez J.Cikhardt K.Turek J.Ullschmied K.Jungwirth Institute of Physics AS CR182 21 Prague 8Czech Republic Czech Technical University in Prague FEE166 27 PragueCzech Republic Nuclear Physics Institute AS CR180 00 Prague 8Czech Republic Institute of Plasma Physics AS CR182 00 Prague 8Czech Republic

The laser system PALS,as a driver of a broad-beam ion source,delivered deuterons which generated neutrons with energies higher than 14 Me V through the 7Li(d,n)8 Be reaction.Deuterons with sub-Me V energy were accelerated from the front surface of a massive CD2 target in the backward direction with respect to the laser beam vector.Simultaneously,neutrons were emitted from the primary CD2 target and a secondary Li F catcher.The total maximum measured neutron yield from 2D(d,n)3He,7Li(d,n)8Be,12C(d,n)13N reactions was ～3.5(±0.5) × 108 neutrons/shot.

关键词： beam–target fusion deuterons laser ion sources lithium neutrons

Development and performance characterization of a compact plasma focus based portable fast neutron generator

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Plasma Science and Technology 2020年第11期22卷 127-135页

作者： Rishi VERMA Ekansh MISHRA Prosenjit DHANG Basanta Kumar DAS Manraj MEENA Lakshman RONGALI Archana SHARMA Pulsed Power&Electromagnetics Division Bhabha Atomic Research Centre FacilityAtchutapuramVishakhapatnam 531011.India Homi Bhabha National Institute AnushaktinagarMumbai 400094India Raja Ramanna Centre for Advanced Technology Rajendra NagarIndore 452013India Variable Energy Cyclotron Centre BidhannagarKolkata 700064India

The design details and performance characterization results of a newly developed plasma focus based compact and portable system(0.5 m×0.5 m×1.2 m,weighing≈100 kg)that produces an average neutron yield of^2×10^8 neutrons/shot(of fast D-D neutrons with typical energy^2.45 Me V)at^1.8 k J energy discharge are reported.From the detailed analysis of the experimental characterization and simulation results of this system,it has been conclusively revealed that specifically in plasma focus devices with larger static inductance:(i)pinch current is a reliable and more valid neutron yield scaling parameter than peak current,(ii)the ratio of pinch/peak current improves as static inductance of the system reduces,(iii)the benign role of the higher static/pinch inductance ratio enables the supply of inductively stored energy in densely pinched plasma with a larger time constant and it is well depicted by the extended dip observed in the discharge current trace,(iv)there is the need to redefine existing index values of the pinch(Ipinch^4.7)and peak(Ipeak^3.9)currents in neutron yield scaling equations to higher values.

关键词： plasma focus neutrons time of flight pinch current peak current plasma pinch pseudospark switch

Deuterated polyethylene nanowire arrays for high-energy density physics

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High Power Laser Science and Engineering 2021年第2期9卷 262-268页

作者： M.G.Capeluto A.Curtis C.Calvi R.Hollinger V.N.Shlyaptsev J.J.Rocca electrical and computer engineering department colorado state universityfort collinsco 80523usa departamento de física universidad de buenos aires-ifiba1428 buenos airesargentina physics department colorado state universityfort collinsco 80523usa

The interaction of intense,ultrashort laser pulses with ordered nanostructure arrays offers a path to the efficient creation of ultra-high-energy density(UHED)matter and the generation of high-energy particles with compact lasers.Irradiation of deuterated nanowires arrays results in a near-solid density environment with extremely high temperatures and large electromagnetic fields in which deuterons are accelerated to multi-megaelectronvolt energies,resulting in deuterium–deuterium(D–D)fusion.Here we focus on the method of fabrication and the characteristics of ordered arrays of deuterated polyethylene nanowires.The irradiation of these array targets with femtosecond pulses of relativistic intensity and joule-level energy creates a micro-scale fusion environment that produced 2×10^(6)neutrons per joule,an increase of about 500 times with respect to flat solid CD2 targets irradiated with the same laser pulses.Irradiation with 8 J laser pulses was measured to generate up to 1.2×10^(7)D–D fusion neutrons per shot.

关键词： deuterated nanowires arrays fusion neutrons ultra-high-energy density plasmas

Using LiF crystals for high-performance neutron imaging with micron-scale resolution

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High Power Laser Science and Engineering 2015年第4期3卷 1-9页

作者： A.Faenov M.Matsubayashi T.Pikuz Y.Fukuda M.Kando R.Yasuda H.Iikura T.Nojima T.Sakai M.Shiozawa R.Kodama Y.Kato Institute for Academic Initiatives Suita Osaka University Joint Institute for High Temperatures Russian Academy of Sciences Quantum Beam Science Center Japan Atomic Energy Agency PPC and Graduate School of Engineering Suita Osaka University Nippon SOKEN Inc. The Graduate School for the Creation of New Photonics Industries

This paper describes an overview of our recent discovery – clear demonstration that Li F crystals can be efficiently used as a high-performance neutron imaging detector based on optically stimulated luminescence of color centers generated by neutron irradiation. It is shown that the neutron images we have obtained are almost free from granular noise, have a spatial resolution of～5.4 μm and a linear response with a dynamic range of at least 103. The high contrast and good sensitivity of Li F crystals allow us to distinguish two holes with less than 2% transmittance difference. We propose to use such detectors in areas where high spatial resolution with high image gradation resolution is needed, including diagnostics of different plasma sources such as laser and z-pinch produced plasmas.

关键词： color centers Li F crystals neutron imaging neutrons plasma diagnostics

Calculation of Cross Section of Radiative Halo—Neutron Capture by ^12C at Stellar Energy with the Asymptotic Normalization Coefficient Method

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Chinese Physics Letters 2003年第1期20卷 49-52页

作者：吴开谡陈永寿等 ChinaInstituteofAtomicEnergy POBox275Beijing102413 ChinaInstituteofAtomicEnergy POBox275Beijing102413 InstituteofTheoreticalPhysics ChineseAcademyofSciencesBeijing100080

The cross section of the direct neutron capture reaction 12C(n,γ)13C(1/2+) is calculated with the asymptotic normalization coefficient method. The result is in good agreement with a recent experiment at low energy. An enormous enhancement of cross section is found for this direct neutron capture in which a p-wave neutron is captured into an 2s1/2 orbit with neutron halo. The possible effect of the neutron halo structure presented in this reaction on the s-process in astrophysics is discussed in general.

关键词： neutrons