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New Opportunities for neutrons in Environmental and Biological Sciences

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Frontiers of Environmental Science & Engineering 2024年第7期18卷 179-186页

作者： Alexander Johs Shuo Qian Leighton Coates Brian H.Davison James G.Elkins Xin Gu Jennifer Morrell-Falvey Hugh O'Neill Jeffrey M.Warren Eric M.Pierce Kenneth Herwig Oak Ridge National Laboratory Oak RidgeTN37831USA

The use of neutron methods in environmental and biological sciences is rapidly emerging and accelerating with the development of new instruments at neutron user *** article,based on a workshop held at Oak Ridge National Laboratory(ORNL),offers insights into the application of neutron techniques in environmental and biological *** highlight recent advances and identify key challenges and potential future research *** include soil and rhizosphere processes,root water dynamics,plant-microbe interactions,structure and dynamics of biological systems,applications in synthetic biology and enzyme engineering,next-generation bioproducts,biomaterials and bioenergy,nanoscale structure,and fluid dynamics of porous materials in *** provide an outlook on emerging opportunities with an emphasis on new capabilities that will be enabled at the Spallation Neutron Source Second Target Station currently under design at *** mission of scientific neutron user facilities worldwide is to enable science using state-of-the-art neutron *** aim to encourage researchers in the environmental and biological research community to explore the unique capability afforded by neutrons at these facilities.

关键词： neutrons Environment Biology Neutron imaging Neutron scattering Second Target Station(STS)

Response of C_(2)H_(2)F_(4)superheated emulsion to quasi-mono-energetic neutrons at low frequency

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Radiation Detection Technology and Methods 2024年第2期8卷 1202-1207页

作者： V.Kumar M.Das S.Ali N.Biswas R.Shil K.Banerjee P.Pallav M.Nandy Saha Institute of Nuclear Physics Kolkata700064India Homi Bhabha National Institute Training School ComplexAnushakti NagarMumbai400094India Physics Department Jadavpur UniversityKolkata700032India Physics Department Visva BharatiSantiniketanWB731235India Variable Energy Cyclotron Centre Kolkata700064India Physics Department Victoria College InstitutionKolkata700009India

Background The response of superheated emulsion detector with different halocarbons as active liquid to poly-energetic and mono-energetic neutrons has been carried out by different *** C_(2)H_(2)F_(4)detectors have not been explored *** liquid has shown the potentiality of sensitivity to low-mass dark *** previous calibration of this liquid was carried out with the poly-energetic *** In the present work,to better characterize the detector with neutrons,it is irradiated with quasi-mono-energetic neutrons and the results are compared with neutrons from *** run the detector for the dark matter search,it is required to calibrate it with neutrons,preferably with mono-energetic *** mono-energetic neutron is not available at all establishments;hence,it was calibrated with quasi-mono-energetic *** The response of superheated emulsion consisting of the droplets of C_(2)H_(2)F_(4)has been studied using the quasi-mono-energetic *** superheated droplets have been fabricated in a visco-elastic gel *** shock waves generated by the passage of the energetic particles are detected by the acoustic sensors coupled to the *** measurement has also been carried out for the blank target and beam-off *** and conclusion It is observed that the(Pvar)response of the emulsion in the low-frequency range is sharper for the quasi-mono-energetic neutrons from 7Li(p,n)reaction and wider for the poly-energetic neutrons from *** fundamental frequency associated with bubble nucleation(FF values)is similar for the neutrons from 7Li-target and 241Am-Be *** precise characterization of such detector is required for the application in neutron measurement as well as for the dark matter search experiment apart from the basic understanding of the radiation-induced bubble nucleation.

关键词： Superheated emulsion Bubble nucleation-Low frequency Quasi-mono-energetic neutrons

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) *** duration of the neutron pulse was ~1.5 *** intensive neutron emission was registered without deuterated *** 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

Nucleation of Supercooled Water by neutrons: Latitude Dependence and Implications for Cloud Modelling

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Atmospheric and Climate Sciences 2024年第2期14卷 221-232页

作者： Peter W. Wilson Elizabeth Wilson-Park Abraham G. Wilson Department of Physics The University at Albany SUNY Albany USA Scripps Institution of Oceanography University of California San Diego USA Philanthropy Australia Sydney Australia The King’ s Institute The King&#8217s School Parramatta Australia

It has recently been shown that incident particles, neutrons, can initiate the freezing in a supercooled water volume. This new finding may have ramifications for the interpretation of both experimental data on the nucleation of laboratory samples of supercooled water and perhaps more importantly on the interpretation of ice nucleation involved in cloud physics. For example, if some fraction of the cloud nucleation previously attributed to dust, soot, or aerosols has been caused by cosmogenic neutrons, fresh consideration is required in the context of climate models. Moreover, as cosmogenic neutrons, most being muon-induced, have much greater flux at high latitudes, estimates of ice nucleates in these regions may be larger than required to accurately model cloud and condensation properties. This discrepancy has been pointed out in IPCC reports. Our paper discusses the connection between the new concept of neutrons nucleating supercooled water and the need for a new source of nucleation in high latitude clouds, ideally causing others to review current data, or to analyse future data with this idea in mind. .

关键词： Climate Models Ice Nucleation neutrons Supercooling

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

Exploiting the unique interaction characteristics of fast neutrons for improved cancer therapy:A radiobiological perspective

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Radiation Medicine and Protection 2024年第1期5卷 24-29页

作者： Festo Kiragga Konstantin Brazovskiy Tomsk Polytechnic University School of Nuclear Power and Electrical Engineering30Lenina AvenueTomsk 634050Russian Federation

Fast neutrons have sufficient energy to liberate recoil protons,alpha particles,and other products when they interact with the nuclei of the target material through scattering and absorption *** interactions with biological tissues occur mainly with hydrogen nuclei and as the protons interact with the hydrogen in tissues,they create dense ionization chains along their tracks thus depositing *** neutron therapy was pioneered by Robert Stone in 1938 a few years after the discovery of the *** main advantage is the limited sensitivity to hypoxia and treatment of slow-growing tumors hence better local *** is where photon therapy has yet to have much *** deposition by fast neutrons in living tissues is higher than in conventional radiotherapy using mega voltage(MV)photon *** higher energy deposition gives fast neutrons a higher relative biological effectiveness(RBE)in dealing with certain *** neutrons also have a higher linear energy transfer(LET)and can reach deep-sited tumors better than photon *** main challenge with Fast neutron therapy has been extreme toxicity in late-reacting ***,fast neutron therapy holds potential for the treatment of certain tumors by leveraging the unique interaction characteristics of fast neutrons with biological *** review therefore intends to bring this uniqueness to light to enhance the understanding of the radiobiological properties of fast neutrons and the advantages associated with its therapy.

关键词： neutrons Radiation therapy Energy Double-strand break(DSB)

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 *** 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 ***,neutrons were emitted from the primary CD2 target and a secondary Li F *** 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

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 *** these collisions,highly charged fast-moving ions carry strong electromagnetic fields that can be effectively treated as photon *** exchange of photons can induce photonuclear and two-photon interactions and excite *** excitation of the ions results in Coulomb dissociation with the emission of photons,neutrons,and other ***,the electromagnetic fields generated by the ions can be sufficiently strong to enforce mutual interactions between the two colliding ***,the two colliding ions experience an electromagnetic force that pushes them in opposite directions,causing a back-to-back correlation in the emitted *** 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)

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 *** 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