Low energy nuclear reactions are possible in condensed matter because of image forces. They result from induced charges at the surface of metals or very polarizable media. The height and width of the Coulomb barrier i...Low energy nuclear reactions are possible in condensed matter because of image forces. They result from induced charges at the surface of metals or very polarizable media. The height and width of the Coulomb barrier in free space can thus be reduced. Nuclear fusion requires also the formation of a compound nucleus in one of its excited states, but two deuterons yield an α particle that has 2 excited states. They are respectively accessible at high or low energies. Since the reduction of the Coulomb barrier depends on the local curvature of the interface, cold fusion becomes autocatalytic, but heat production is controllable. Even microbes, plants and animals can produce transmutations. They are also due to image forces. This solves a basic problem in nuclear physics and there are possible applications: facilitated synthesis of superheavy elements and development of a new type of energy sources. They are moderate, but safe.展开更多
The dissipation phenomenon in the heavy-ion reaction at incident energy near the Fermi energy is studied by simulating the reaction ^129Xe+^129Sn with the isospin-dependent quantum molecular dynamics model. The calcu...The dissipation phenomenon in the heavy-ion reaction at incident energy near the Fermi energy is studied by simulating the reaction ^129Xe+^129Sn with the isospin-dependent quantum molecular dynamics model. The calculations involving a proper prescription of implementing the Pauli exclusion principle show that the isotropy ratio measured by free protons emitted in the reaction at energy slightly higher than the Fermi energy is in agreement with the experimental data recently released by the INDRA collaboration. A feasible value of the Pauli-blocking factor is estimated by comparing the theoretical results with the experimental data for the energy range considered here.展开更多
We investigate the impact of inelastic collisions between dark matter(DM)and heavy cosmic ray(CR)nuclei on CR propagation.We approximate the fragmentation cross-sections for DM-CR collisions using collider-measured pr...We investigate the impact of inelastic collisions between dark matter(DM)and heavy cosmic ray(CR)nuclei on CR propagation.We approximate the fragmentation cross-sections for DM-CR collisions using collider-measured proton-nuclei scattering cross-sections,allowing us to assess how these collisions affect the spectra of CR boron and carbon.We derive new CR spectra from DM-CR collisions by incorporating their cross-sections into the source terms and solving the diffusion equation for the complete network of reactions involved in generating secondary species.In a specific example with a coupling strength of b_(χ)=0.1 and a DM mass of m_(χ)=0.1 GeV,considering a simplified scenario where DM interacts exclusively with oxygen,a notable modification in the boron-to-carbon spectrum due to the DM-CR interaction is observed.Particularly,the peak within the spectrum,spanning from 0.1 to 10 GeV,experiences an enhancement of approximately 1.5 times.However,in a more realistic scenario where DM particles interact with all CRs,this peak can be amplified to twice its original value.Utilizing the latest data from AMS-02 and DAMPE on the boron-to-carbon ratio,we estimate a 95%upper limit for the effective inelastic cross-section of DM-proton as a function of DM mass.Our findings reveal that at m_(χ)?2 MeV,the effective inelastic cross-section between DM and protons must be less than O(10^(-32))cm^(2).展开更多
Based on the theory of relativistic superstrong magnetic fields (SMFs), by using the method of Thomas-Fermi-Dirac approximations, we investigate the problem of strong electron screening (SES) in SMFs and the influ...Based on the theory of relativistic superstrong magnetic fields (SMFs), by using the method of Thomas-Fermi-Dirac approximations, we investigate the problem of strong electron screening (SES) in SMFs and the influence of SES on the nuclear reaction of 23Mg (p, Y)24A1. Our calculations show that the nuclear reaction will be markedly effected by the SES in SMFs in the surface of magnetars. Our calculated screening rates can increase two orders of magnitude due to SES in SMFs.展开更多
In this work,we explore the use of an iterative Bayesian Monte Carlo(iBMC)method for nuclear data evaluation within a TALYS Evaluated Nuclear Data Library(TENDL)framework.The goal is to probe the model and parameter s...In this work,we explore the use of an iterative Bayesian Monte Carlo(iBMC)method for nuclear data evaluation within a TALYS Evaluated Nuclear Data Library(TENDL)framework.The goal is to probe the model and parameter space of the TALYS code system to find the optimal model and parameter sets that reproduces selected experimental data.The method involves the simultaneous variation of many nuclear reaction models as well as their parameters included in the TALYS code.The‘best’model set with its parameter set was obtained by comparing model calculations with selected experimental data.Three experimental data types were used:(1)reaction cross sections,(2)residual production cross sections,and(3)the elastic angular distributions.To improve our fit to experimental data,we update our‘best’parameter set—the file that maximizes the likelihood function—in an iterative fashion.Convergence was determined by monitoring the evolution of the maximum likelihood estimate(MLE)values and was considered reached when the relative change in the MLE for the last two iterations was within 5%.Once the final‘best’file is identified,we infer parameter uncertainties and covariance information to this file by varying model parameters around this file.In this way,we ensured that the parameter distributions are centered on our evaluation.The proposed method was applied to the evaluation of p+^(59)Co between 1 and 100 MeV.Finally,the adjusted files were compared with experimental data from the EXFOR database as well as with evaluations from the TENDL-2019,JENDL/He-2007 and JENDL-4.0/HE nuclear data libraries.展开更多
Hundred years after the conjecture of the British astronomer Eddington that the sun is powered by nuclear fusion of hydrogen, new physics theory may help make energy harvesting by nuclear fusion soon a reality. Resear...Hundred years after the conjecture of the British astronomer Eddington that the sun is powered by nuclear fusion of hydrogen, new physics theory may help make energy harvesting by nuclear fusion soon a reality. Researchers as well as investors funding fusion megaprojects are asked to deal with new relativistic corrections for mass and energy proposed by Suleiman in his Information Relativity Theory (IRT). These corrections were calculated in this contribution. It will help to decide whether a venture will be successful and to save big investments when in doubt. The assumed optimal kinetic energy for controlled nuclear fusion must be corrected to a somewhat higher level. At very high kinetic energy in the upper GeV range, it remains not enough baryonic mass to be transformed in energy. The fusion probability faded out to zero already at the golden limit of the recession speed of between target nucleon and projectile nucleon. Cold nuclear fusion, if ever possible, is recommended for protons rather than deuterons at highest experimental possible temperatures around 1000 (K) and needs fine-tuned kinetic nucleon energy. It would be also of interest whether a golden ratio based nuclear fuel confinement chamber could be beneficial. In this connection, also cold nuclear fusion setups should be discussed. Nature is governed by the golden ratio and criticality of physical systems influenced by it, and nuclear physics is not an exception. Computer simulations of the underlying controlled nuclear fusion processes should gain profit from IRT corrected starting information and may tackle anew possible low energy nuclear transmutations considering the wave-like dark components of matter and energy.展开更多
Tritium (3^H) in excess of the atmospheric values was found at volcanic Lakes Pavin (France), Laacher (Germany) and Nemrut (Turkey), as well as Kilauea Volcano at Hawaii (USA) and other volcanoes. Because 3^...Tritium (3^H) in excess of the atmospheric values was found at volcanic Lakes Pavin (France), Laacher (Germany) and Nemrut (Turkey), as well as Kilauea Volcano at Hawaii (USA) and other volcanoes. Because 3^H has a short half-life of 12.3 years, the tritium and the resulting 3^He must have formed recently in the Earth. The result suggests that nuclear reactions may generate a significant amount of tritium in the interior of the Earth, although we have not yet learned what the reaction mechanism may be responsible. The nuclear reaction that can be responsible for tritium production in the Earth is probably a new research field in physics science. Nuclear reactions that generate tritium might be a source of "missing" energy (heat) in the interior of the Earth. Finding in-situ 3^H in the mantle may exhibit an alternative explanation of 3^He origin in the deep Earth.展开更多
This paper reports on an experiment for testing natural nuclear fusion at low temperature searching for evidence of the origin of 3He from natural nuclear fusion in deep Earth. The experiment was carried out using deu...This paper reports on an experiment for testing natural nuclear fusion at low temperature searching for evidence of the origin of 3He from natural nuclear fusion in deep Earth. The experiment was carried out using deuterium-loaded titanium foil samples and powder sample. Detection of charged particle was carried out using a low-level charged particle spectrometer. An A1 foil was used as an energy absorber for identification of charged particle. Although the counting rate is very low in the experiment, the emission of energetic particle from the sample is observed and the particle is identified as a proton having energy about 2.8 MeV after exiting the titanium sample. This work provides a positive result for the emission of charged particle in the deuterium-loaded titanium foil samples at low temperature, but a negative result for the deuterium-loaded titanium powder sample. The average reaction yield is deduced to be (0.46±0.08) protons/h for the foil samples. With the suggestion that the proton originates from d-d reaction, we calculate the reaction rate for d-d reaction, and the obtained result is 1.4×10^-24 fusion/d-d.sec. The negative result of the deuterium-loaded titanium powder sample suggests that the reaction yield might be correlated with the density or microscopic variables of deuterium-loaded titanium materials. The negative result also indicates that d-d reaction catalysed by μ-meson from cosmic ray can be excluded in the samples in this experiment.展开更多
Fluorine contaminates the environment. The study of fluorine contamination profile can be made easy by the use of nuclear analytic method. Measurement of prompt gamma emitted from bombarding fluorine polluted environm...Fluorine contaminates the environment. The study of fluorine contamination profile can be made easy by the use of nuclear analytic method. Measurement of prompt gamma emitted from bombarding fluorine polluted environmental sample with proton beam from accelerator provides rapid assessment of fluorine contamination. In this paper, 340 keV proton beam induced F 19 (P,αγ) O 16 reaction is performed, measurement of prompt gamma 6130 keV gives fluorine content in the soil and leaves of plants (parasol, cotton and glossy privet), taken from the fluorine polluted area.展开更多
The interaction of the charged particles in the new Unitary Quantum theory isconsidered. It is shown that the distance of approachment of deuterons to each other verystrongly depends on the phase of the wave function ...The interaction of the charged particles in the new Unitary Quantum theory isconsidered. It is shown that the distance of approachment of deuterons to each other verystrongly depends on the phase of the wave function and not only upon the energy. This thesis isnot discussed in the conventional quantum theory. It can easily explain the experiments on thecold nuclear fusion.展开更多
The Shanghai laser electron gamma source(SLEGS)is a powerful tool for exploring photonuclear physics,such as giant dipole resonance(GDR)and pygmy dipole resonance,which are the main mechanisms of collective nuclear mo...The Shanghai laser electron gamma source(SLEGS)is a powerful tool for exploring photonuclear physics,such as giant dipole resonance(GDR)and pygmy dipole resonance,which are the main mechanisms of collective nuclear motion.The goal of the SLEGS neutron time-of-flight(TOF)spectrometer is to measure GDR and specific nuclear structures in the energy region above the neutron threshold.The SLEGS TOF spectrometer was designed to hold 20 sets of EJ301 and LaBr3 detectors.Geant4 was used to simulate the efficiency of each detector and the entire spectrometer,which provides a reference for the selection of detectors and layout of the SLEGS TOF spectrometer.Under the events of 208Pb,implementations of coincidence and time-of-flight technology for complex experiments are available;thus,and neutron decay events can be separated.The performance of SLEGS TOF spectrometer was systematically evaluated using offline experiments,in which the time resolution reached approximately 0.9 ns.展开更多
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 under...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.展开更多
The experimental data of elastic scattering angular distributions for 9Be,10B,11B,12C,13C,15N,and 16O targets from 4.5 to 131.8 MeV and 7Li target from 8.0 to 42.0 MeV are fitted to realize the global phenomenological...The experimental data of elastic scattering angular distributions for 9Be,10B,11B,12C,13C,15N,and 16O targets from 4.5 to 131.8 MeV and 7Li target from 8.0 to 42.0 MeV are fitted to realize the global phenomenological optical potentials(GPOPs)for the 7Li-induced reactions on 1p-shell nuclei.Thus,the 7Li elastic scattering from the 1p-shell nuclei can be systematically described using the established GPOPs.The elastic scattering angular distributions are also reanalyzed using a microscopic method within the framework of the new version of double folding S?o Paulo potential(SPP2).To better describe the elastic scattering at backward angles,the contribution of elastic transfer is further estimated by the distorted wave Born approximation(DWBA)method.Based on the obtained GPOPs,the inelastic scattering angular distributions are also obtained through the coupled channels(CC)method for the different excited states.展开更多
Fast radio bursts (FRBs) are puzzling, millisecond, energetic radio transients with no discernible source; observations show no counterparts in other frequency bands. The birth of a quark star from a parent neutron ...Fast radio bursts (FRBs) are puzzling, millisecond, energetic radio transients with no discernible source; observations show no counterparts in other frequency bands. The birth of a quark star from a parent neutron star experiencing a quark nova - previously thought undetectable when born in isolation - provides a natural explanation for the emission characteristics of FRBs. The generation of unstable r-process elements in the quark nova ejecta provides millisecond exponential injection of electrons into the surrounding strong magnetic field at the parent neutron star's light cylinder via β-decay. This radio synchrotron emission has a total duration of hundreds of milliseconds and matches the observed spectrum while reducing the inferred dispersion measure by approximately 200 cm-3 pc. The model allows indirect measurement of neutron star magnetic fields and periods in addition to providing astronomical measurements of β-decay chains of unstable neutron rich nuclei. Using this model, we can calculate expected FRB average energies (- 1041 erg) and spectral shapes, and provide a theoretical framework for determining distances.展开更多
The steady equilibrium conditions for a mixed gas of neutrons, protons, electrons, positrons and radiation fields (abbreviated as npe^± gas) with or without external neutrino flux are investigated, and a genera...The steady equilibrium conditions for a mixed gas of neutrons, protons, electrons, positrons and radiation fields (abbreviated as npe^± gas) with or without external neutrino flux are investigated, and a general chemical potential equilibrium equation μn = μp + Cμe is obtained to describe the steady equilibrium at high temperatures (T 〉 10^9 K). An analytic fitting formula of coefficient C is presented for the sake of simplicity, when neutrinos and antineutrinos are transparent. It is a simple method to estimate the electron fraction for the steady equilibrium npe^± gas that adopts the corresponding equilibrium condition. As an example, we apply this method to the GRB accretion disk and confirm that the composition in the inner region is approximately in equilibrium when the accretion rate is low. For the case with external neutrino flux, we calculate the initial electron fraction of neutrino-driven wind from the proto-neutron star model M15-l1-r1. The results show that the improved equilibrium condition makes the electron fraction decrease significantly more than the case μn = μp + μe when the time is less than 5s post bounce, which may be useful for r-process nucleosynthesis models.展开更多
Dramatic extensions of experimental possibilities (spacecraft RHESSI, CORONAS-F and others) in solar gamma-ray astronomy call for urgent, detailed theoretical consideration of a set of physical problems of solar activ...Dramatic extensions of experimental possibilities (spacecraft RHESSI, CORONAS-F and others) in solar gamma-ray astronomy call for urgent, detailed theoretical consideration of a set of physical problems of solar activity and solar-terrestrial relationships that earlier may have only been outlined. Here we undertake a theoretical analysis of issues related to the production of gamma-radiation in the processes of interactions of energetic (accelerated) heavy and middle nuclei with the nuclei of the solar atmosphere (the so-called i-j interactions). We also make an estimate of the contribution of these interactions to the formation of nuclear and isotopic abundances of the solar atmosphere in the range of light and rare elements. The analysis is carried out for solar flares in the wide range of their intensities. We compare our theoretical estimates with RHESSI observations for the flare of 2002 July 23. It was shown that the 24Mg gamma-ray emission in this event was produced by the newly generated Mg nuclei. With a high probability, the gamma-ray line emission of 28Si nuclei from this flare was generated by the same processes.展开更多
Taking into account the effect of electron screening on electron energy and electron capture threshold energy, by using the method of Shell-Model Monte Carlo and random phase approximation theory, we investigate the c...Taking into account the effect of electron screening on electron energy and electron capture threshold energy, by using the method of Shell-Model Monte Carlo and random phase approximation theory, we investigate the capture rates of chromium isotopes with strong electron screening according to the linear response theory screening model. Strong screening rates can decrease by about 40.43% (e.g., for 6Cr at T9 = 3.44, Ye = 0.43). Our conclusions may be helpful to researches on supernova explosions and related numerical simulation methods.展开更多
When a daughter nucleus produced by electron capture takes part in a level transition from an excited state to its ground state in accreting neutron star crusts, ther- mal energy will be released and heat the crust, i...When a daughter nucleus produced by electron capture takes part in a level transition from an excited state to its ground state in accreting neutron star crusts, ther- mal energy will be released and heat the crust, increasing crust temperature and chang- ing subsequent carbon ignition conditions. Previous studies show that the theoretical carbon ignition depth is deeper than the value inferred from observations because the thermal energy is not sufficient. In this paper, we present the de-excited energy from electron capture of rp-process ash before carbon ignition, especially for the initial evo- lution stage of rp-process ash, by using a level-to-level transition method. We find the theoretical column density of carbon ignition in the resulting superbursts and compare it with observations. The calculation of the electron capture process is based on a more reliable level-to-level transition, adopting new data from experiments or theo- retical models (e.g., large-scale shell model and proton-neutron quasi-particle random phase approximation). The new carbon ignition depth is estimated by fitting from previous results of a nuclear reaction network. Our results show the average de-excited energy from electron capture before carbon ignition is -0.026 MeV/u, which is significantly larger than the previous results. This energy is beneficial for enhancing the crust's temperature and decreasing the carbon ignition depth of superbursts.展开更多
Neutrinos play an important role in stellar evolution.They are produced by nuclear reactions or thermal processes.Using the stellar evolution code Modules for Experiments in Stellar Astrophysics(MESA),we study stellar...Neutrinos play an important role in stellar evolution.They are produced by nuclear reactions or thermal processes.Using the stellar evolution code Modules for Experiments in Stellar Astrophysics(MESA),we study stellar neutrino luminosity with different masses.The neutrino luminosities of stars with different initial masses at different evolutionary stages are simulated.We find that the neutrino flux of a star with 1 M⊙ mass at an evolutionary age of 4.61×10^9 yr is consistent with that of the Sun.In general,neutrinos are produced by nuclear reactions,and the neutrino luminosity of stars is about one or two magnitudes lower than the photo luminosity.However,neutrino luminosity can exceed photo luminosity during the helium flash which can occur for stars with a mass lower than 8 M⊙.Although the helium flash does not produce neutrinos,plasma decay,one of the thermal processes,can efficiently make neutrinos during this stage.Due to the high mass-loss rate,a star with a mass of 9 M⊙ does not undergo the helium flash.Its neutrinos mainly originate from nuclear reactions until the end of the AGB stage.At the end of the AGB stage,its neutrino luminosity results from plasma decay which is triggered by the gravitational energy release because of the stellar core contracting.展开更多
Based on the shell-model Monte Carlo method and random phase approximation theory, the neutrino energy spectrum (NES) and the electron capture (EC) of ^56Fe, ^56Co, ^56Ni, ^56Mn, ^56Cr and ^56V are investigated in...Based on the shell-model Monte Carlo method and random phase approximation theory, the neutrino energy spectrum (NES) and the electron capture (EC) of ^56Fe, ^56Co, ^56Ni, ^56Mn, ^56Cr and ^56V are investigated in presupemova surroundings. The results show that the EC rates are affected greatly at different densities and temperatures. The rates increase greatly and even exceed six orders of magnitude at lower temperature. On the other hand, the NES is very sensitive to stellar temperature and electron energy. The higher the temperature and the lower the electron energy, the larger the influence on NES is. For example, the maxima of NES in the ground state are 9.02, 160, 80, 24.01, 0.44, 1.42 me c^2 for ^56Fe, ^56Co, ^56Ni, ^56Mn, ^56Cr and ^56V respectively at ρ7 = 10.7, Ye = 0.45 and T9 = 15. Furthermore, the influence on NES due to EC for different nuclei has some otherness because of different Qo-values. For example, the spectrum of ^56Co shows a double bump structure.展开更多
文摘Low energy nuclear reactions are possible in condensed matter because of image forces. They result from induced charges at the surface of metals or very polarizable media. The height and width of the Coulomb barrier in free space can thus be reduced. Nuclear fusion requires also the formation of a compound nucleus in one of its excited states, but two deuterons yield an α particle that has 2 excited states. They are respectively accessible at high or low energies. Since the reduction of the Coulomb barrier depends on the local curvature of the interface, cold fusion becomes autocatalytic, but heat production is controllable. Even microbes, plants and animals can produce transmutations. They are also due to image forces. This solves a basic problem in nuclear physics and there are possible applications: facilitated synthesis of superheavy elements and development of a new type of energy sources. They are moderate, but safe.
基金Supported by the National Natural Science Foundation Of China under Grant Nos 11265013,11175074,11264033 and 11464040
文摘The dissipation phenomenon in the heavy-ion reaction at incident energy near the Fermi energy is studied by simulating the reaction ^129Xe+^129Sn with the isospin-dependent quantum molecular dynamics model. The calculations involving a proper prescription of implementing the Pauli exclusion principle show that the isotropy ratio measured by free protons emitted in the reaction at energy slightly higher than the Fermi energy is in agreement with the experimental data recently released by the INDRA collaboration. A feasible value of the Pauli-blocking factor is estimated by comparing the theoretical results with the experimental data for the energy range considered here.
基金supported by the National Key Research and Development Program of China(2022YFF0503304,2020YFC2201600,2018YFA0404504 and 2018YFA0404601)the Ministry of Science and Technology of China(2020SKA0110402,2020SKA0110401 and 2020SKA0110100)+4 种基金the National Natural Science Foundation of China(11890691,12205388 and 12220101003)the CAS Project for Young Scientists in Basic Research(YSBR-061,YSBR-092)the China Manned Space Project with No.CMS-CSST-2021(A02,A03 and B01)the Major Key Project of PCLthe 111 project(B20019)。
文摘We investigate the impact of inelastic collisions between dark matter(DM)and heavy cosmic ray(CR)nuclei on CR propagation.We approximate the fragmentation cross-sections for DM-CR collisions using collider-measured proton-nuclei scattering cross-sections,allowing us to assess how these collisions affect the spectra of CR boron and carbon.We derive new CR spectra from DM-CR collisions by incorporating their cross-sections into the source terms and solving the diffusion equation for the complete network of reactions involved in generating secondary species.In a specific example with a coupling strength of b_(χ)=0.1 and a DM mass of m_(χ)=0.1 GeV,considering a simplified scenario where DM interacts exclusively with oxygen,a notable modification in the boron-to-carbon spectrum due to the DM-CR interaction is observed.Particularly,the peak within the spectrum,spanning from 0.1 to 10 GeV,experiences an enhancement of approximately 1.5 times.However,in a more realistic scenario where DM particles interact with all CRs,this peak can be amplified to twice its original value.Utilizing the latest data from AMS-02 and DAMPE on the boron-to-carbon ratio,we estimate a 95%upper limit for the effective inelastic cross-section of DM-proton as a function of DM mass.Our findings reveal that at m_(χ)?2 MeV,the effective inelastic cross-section between DM and protons must be less than O(10^(-32))cm^(2).
基金supported in part by the National Natural Science Foundation of China through grant No. 11565020the Natural Science Foundation of Hainan province under grant No. 114012the Undergraduate Innovation Program of Hainan province under grant No. 20130139
文摘Based on the theory of relativistic superstrong magnetic fields (SMFs), by using the method of Thomas-Fermi-Dirac approximations, we investigate the problem of strong electron screening (SES) in SMFs and the influence of SES on the nuclear reaction of 23Mg (p, Y)24A1. Our calculations show that the nuclear reaction will be markedly effected by the SES in SMFs in the surface of magnetars. Our calculated screening rates can increase two orders of magnitude due to SES in SMFs.
基金Funding Open Access funding provided by Lib4RI–Library for the Research Institutes within the ETH Domain:Eawag,Empa,PSI&WSLthe Paul Scherrer Institute through the NES/GFA-ABE Cross Project.
文摘In this work,we explore the use of an iterative Bayesian Monte Carlo(iBMC)method for nuclear data evaluation within a TALYS Evaluated Nuclear Data Library(TENDL)framework.The goal is to probe the model and parameter space of the TALYS code system to find the optimal model and parameter sets that reproduces selected experimental data.The method involves the simultaneous variation of many nuclear reaction models as well as their parameters included in the TALYS code.The‘best’model set with its parameter set was obtained by comparing model calculations with selected experimental data.Three experimental data types were used:(1)reaction cross sections,(2)residual production cross sections,and(3)the elastic angular distributions.To improve our fit to experimental data,we update our‘best’parameter set—the file that maximizes the likelihood function—in an iterative fashion.Convergence was determined by monitoring the evolution of the maximum likelihood estimate(MLE)values and was considered reached when the relative change in the MLE for the last two iterations was within 5%.Once the final‘best’file is identified,we infer parameter uncertainties and covariance information to this file by varying model parameters around this file.In this way,we ensured that the parameter distributions are centered on our evaluation.The proposed method was applied to the evaluation of p+^(59)Co between 1 and 100 MeV.Finally,the adjusted files were compared with experimental data from the EXFOR database as well as with evaluations from the TENDL-2019,JENDL/He-2007 and JENDL-4.0/HE nuclear data libraries.
文摘Hundred years after the conjecture of the British astronomer Eddington that the sun is powered by nuclear fusion of hydrogen, new physics theory may help make energy harvesting by nuclear fusion soon a reality. Researchers as well as investors funding fusion megaprojects are asked to deal with new relativistic corrections for mass and energy proposed by Suleiman in his Information Relativity Theory (IRT). These corrections were calculated in this contribution. It will help to decide whether a venture will be successful and to save big investments when in doubt. The assumed optimal kinetic energy for controlled nuclear fusion must be corrected to a somewhat higher level. At very high kinetic energy in the upper GeV range, it remains not enough baryonic mass to be transformed in energy. The fusion probability faded out to zero already at the golden limit of the recession speed of between target nucleon and projectile nucleon. Cold nuclear fusion, if ever possible, is recommended for protons rather than deuterons at highest experimental possible temperatures around 1000 (K) and needs fine-tuned kinetic nucleon energy. It would be also of interest whether a golden ratio based nuclear fuel confinement chamber could be beneficial. In this connection, also cold nuclear fusion setups should be discussed. Nature is governed by the golden ratio and criticality of physical systems influenced by it, and nuclear physics is not an exception. Computer simulations of the underlying controlled nuclear fusion processes should gain profit from IRT corrected starting information and may tackle anew possible low energy nuclear transmutations considering the wave-like dark components of matter and energy.
基金supported by President Foundation of the China Institute of Atomic Energy (No.YZ-0704)
文摘Tritium (3^H) in excess of the atmospheric values was found at volcanic Lakes Pavin (France), Laacher (Germany) and Nemrut (Turkey), as well as Kilauea Volcano at Hawaii (USA) and other volcanoes. Because 3^H has a short half-life of 12.3 years, the tritium and the resulting 3^He must have formed recently in the Earth. The result suggests that nuclear reactions may generate a significant amount of tritium in the interior of the Earth, although we have not yet learned what the reaction mechanism may be responsible. The nuclear reaction that can be responsible for tritium production in the Earth is probably a new research field in physics science. Nuclear reactions that generate tritium might be a source of "missing" energy (heat) in the interior of the Earth. Finding in-situ 3^H in the mantle may exhibit an alternative explanation of 3^He origin in the deep Earth.
基金Project supported by President Foundation of China Institute of Atomic Energy (Grant No YZ0714)
文摘This paper reports on an experiment for testing natural nuclear fusion at low temperature searching for evidence of the origin of 3He from natural nuclear fusion in deep Earth. The experiment was carried out using deuterium-loaded titanium foil samples and powder sample. Detection of charged particle was carried out using a low-level charged particle spectrometer. An A1 foil was used as an energy absorber for identification of charged particle. Although the counting rate is very low in the experiment, the emission of energetic particle from the sample is observed and the particle is identified as a proton having energy about 2.8 MeV after exiting the titanium sample. This work provides a positive result for the emission of charged particle in the deuterium-loaded titanium foil samples at low temperature, but a negative result for the deuterium-loaded titanium powder sample. The average reaction yield is deduced to be (0.46±0.08) protons/h for the foil samples. With the suggestion that the proton originates from d-d reaction, we calculate the reaction rate for d-d reaction, and the obtained result is 1.4×10^-24 fusion/d-d.sec. The negative result of the deuterium-loaded titanium powder sample suggests that the reaction yield might be correlated with the density or microscopic variables of deuterium-loaded titanium materials. The negative result also indicates that d-d reaction catalysed by μ-meson from cosmic ray can be excluded in the samples in this experiment.
文摘Fluorine contaminates the environment. The study of fluorine contamination profile can be made easy by the use of nuclear analytic method. Measurement of prompt gamma emitted from bombarding fluorine polluted environmental sample with proton beam from accelerator provides rapid assessment of fluorine contamination. In this paper, 340 keV proton beam induced F 19 (P,αγ) O 16 reaction is performed, measurement of prompt gamma 6130 keV gives fluorine content in the soil and leaves of plants (parasol, cotton and glossy privet), taken from the fluorine polluted area.
文摘The interaction of the charged particles in the new Unitary Quantum theory isconsidered. It is shown that the distance of approachment of deuterons to each other verystrongly depends on the phase of the wave function and not only upon the energy. This thesis isnot discussed in the conventional quantum theory. It can easily explain the experiments on thecold nuclear fusion.
基金supported by the National Natural Science Foundation of China (Nos.12275338,12005280,11905274 and 11875311)the Key Laboratory of Nuclear Data foundation (JCKY2022201C152)+1 种基金National key research and development program (No.2022YFA1602404)the Strategic Priority Research Program of the CAS (No.XDB34030000).
文摘The Shanghai laser electron gamma source(SLEGS)is a powerful tool for exploring photonuclear physics,such as giant dipole resonance(GDR)and pygmy dipole resonance,which are the main mechanisms of collective nuclear motion.The goal of the SLEGS neutron time-of-flight(TOF)spectrometer is to measure GDR and specific nuclear structures in the energy region above the neutron threshold.The SLEGS TOF spectrometer was designed to hold 20 sets of EJ301 and LaBr3 detectors.Geant4 was used to simulate the efficiency of each detector and the entire spectrometer,which provides a reference for the selection of detectors and layout of the SLEGS TOF spectrometer.Under the events of 208Pb,implementations of coincidence and time-of-flight technology for complex experiments are available;thus,and neutron decay events can be separated.The performance of SLEGS TOF spectrometer was systematically evaluated using offline experiments,in which the time resolution reached approximately 0.9 ns.
基金supported by the Institute for Basic ScienceKorea under the project code IBS-R012-D1by the Ultrashort Quantum Beam Facility(UQBF)operation program(No.140011)through APRI,GIST。
文摘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.
基金Supported by the National Natural Science Foundation of China(11405099,11575291,12065003)the Natural Science Foundation of Shanxi Province,China(202103021224309,201901D111317)a part of IAEA Coordinated Research Projects(CRPs)on Recommended Input Parameter Library(RIPL)for Fission Cross Section Calculations(20464)。
文摘The experimental data of elastic scattering angular distributions for 9Be,10B,11B,12C,13C,15N,and 16O targets from 4.5 to 131.8 MeV and 7Li target from 8.0 to 42.0 MeV are fitted to realize the global phenomenological optical potentials(GPOPs)for the 7Li-induced reactions on 1p-shell nuclei.Thus,the 7Li elastic scattering from the 1p-shell nuclei can be systematically described using the established GPOPs.The elastic scattering angular distributions are also reanalyzed using a microscopic method within the framework of the new version of double folding S?o Paulo potential(SPP2).To better describe the elastic scattering at backward angles,the contribution of elastic transfer is further estimated by the distorted wave Born approximation(DWBA)method.Based on the obtained GPOPs,the inelastic scattering angular distributions are also obtained through the coupled channels(CC)method for the different excited states.
文摘Fast radio bursts (FRBs) are puzzling, millisecond, energetic radio transients with no discernible source; observations show no counterparts in other frequency bands. The birth of a quark star from a parent neutron star experiencing a quark nova - previously thought undetectable when born in isolation - provides a natural explanation for the emission characteristics of FRBs. The generation of unstable r-process elements in the quark nova ejecta provides millisecond exponential injection of electrons into the surrounding strong magnetic field at the parent neutron star's light cylinder via β-decay. This radio synchrotron emission has a total duration of hundreds of milliseconds and matches the observed spectrum while reducing the inferred dispersion measure by approximately 200 cm-3 pc. The model allows indirect measurement of neutron star magnetic fields and periods in addition to providing astronomical measurements of β-decay chains of unstable neutron rich nuclei. Using this model, we can calculate expected FRB average energies (- 1041 erg) and spectral shapes, and provide a theoretical framework for determining distances.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10733010, 10673010 and 10573016)the National Basic Research Program of China (2009CB824800)+2 种基金the Scientific Research Funds of Sichuan Provincial Education Department (10ZC014, 2009ZB087)China West Normal University(09A004)Graduate Innovation Funds of USTC
文摘The steady equilibrium conditions for a mixed gas of neutrons, protons, electrons, positrons and radiation fields (abbreviated as npe^± gas) with or without external neutrino flux are investigated, and a general chemical potential equilibrium equation μn = μp + Cμe is obtained to describe the steady equilibrium at high temperatures (T 〉 10^9 K). An analytic fitting formula of coefficient C is presented for the sake of simplicity, when neutrinos and antineutrinos are transparent. It is a simple method to estimate the electron fraction for the steady equilibrium npe^± gas that adopts the corresponding equilibrium condition. As an example, we apply this method to the GRB accretion disk and confirm that the composition in the inner region is approximately in equilibrium when the accretion rate is low. For the case with external neutrino flux, we calculate the initial electron fraction of neutrino-driven wind from the proto-neutron star model M15-l1-r1. The results show that the improved equilibrium condition makes the electron fraction decrease significantly more than the case μn = μp + μe when the time is less than 5s post bounce, which may be useful for r-process nucleosynthesis models.
基金Supported by the National Natural Science Foundation of China.
文摘Dramatic extensions of experimental possibilities (spacecraft RHESSI, CORONAS-F and others) in solar gamma-ray astronomy call for urgent, detailed theoretical consideration of a set of physical problems of solar activity and solar-terrestrial relationships that earlier may have only been outlined. Here we undertake a theoretical analysis of issues related to the production of gamma-radiation in the processes of interactions of energetic (accelerated) heavy and middle nuclei with the nuclei of the solar atmosphere (the so-called i-j interactions). We also make an estimate of the contribution of these interactions to the formation of nuclear and isotopic abundances of the solar atmosphere in the range of light and rare elements. The analysis is carried out for solar flares in the wide range of their intensities. We compare our theoretical estimates with RHESSI observations for the flare of 2002 July 23. It was shown that the 24Mg gamma-ray emission in this event was produced by the newly generated Mg nuclei. With a high probability, the gamma-ray line emission of 28Si nuclei from this flare was generated by the same processes.
基金supported in part by the National Natural Science Foundation of China (Grant Nos. 11565020 and 10773005)the Counterpart Foundation of Sanya (Grant 2016PT43)+2 种基金the Special Foundation of Science and Technology Cooperation for Advanced Academy and Region of Sanya (Grant 2016YD28)the Scientific Research Starting Foundation for 515 Talented Project of Hainan Tropical Ocean University (Grant RHDRC201701)the Natural Science Foundation of Hainan Province (Grant No. 114012)
文摘Taking into account the effect of electron screening on electron energy and electron capture threshold energy, by using the method of Shell-Model Monte Carlo and random phase approximation theory, we investigate the capture rates of chromium isotopes with strong electron screening according to the linear response theory screening model. Strong screening rates can decrease by about 40.43% (e.g., for 6Cr at T9 = 3.44, Ye = 0.43). Our conclusions may be helpful to researches on supernova explosions and related numerical simulation methods.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11273020, 11305133 and U1331121)China Scholarship (Grant No. 2011851096)the Science Foundation of China West Normal University (Grant No. 11B007)
文摘When a daughter nucleus produced by electron capture takes part in a level transition from an excited state to its ground state in accreting neutron star crusts, ther- mal energy will be released and heat the crust, increasing crust temperature and chang- ing subsequent carbon ignition conditions. Previous studies show that the theoretical carbon ignition depth is deeper than the value inferred from observations because the thermal energy is not sufficient. In this paper, we present the de-excited energy from electron capture of rp-process ash before carbon ignition, especially for the initial evo- lution stage of rp-process ash, by using a level-to-level transition method. We find the theoretical column density of carbon ignition in the resulting superbursts and compare it with observations. The calculation of the electron capture process is based on a more reliable level-to-level transition, adopting new data from experiments or theo- retical models (e.g., large-scale shell model and proton-neutron quasi-particle random phase approximation). The new carbon ignition depth is estimated by fitting from previous results of a nuclear reaction network. Our results show the average de-excited energy from electron capture before carbon ignition is -0.026 MeV/u, which is significantly larger than the previous results. This energy is beneficial for enhancing the crust's temperature and decreasing the carbon ignition depth of superbursts.
基金support of the National Natural Science Foundation of China(Grant Nos.11763007,11473024,11463005,11863005,11803026 and 11503008)the Tianshan Youth Project of Xinjiang(2017Q014)
文摘Neutrinos play an important role in stellar evolution.They are produced by nuclear reactions or thermal processes.Using the stellar evolution code Modules for Experiments in Stellar Astrophysics(MESA),we study stellar neutrino luminosity with different masses.The neutrino luminosities of stars with different initial masses at different evolutionary stages are simulated.We find that the neutrino flux of a star with 1 M⊙ mass at an evolutionary age of 4.61×10^9 yr is consistent with that of the Sun.In general,neutrinos are produced by nuclear reactions,and the neutrino luminosity of stars is about one or two magnitudes lower than the photo luminosity.However,neutrino luminosity can exceed photo luminosity during the helium flash which can occur for stars with a mass lower than 8 M⊙.Although the helium flash does not produce neutrinos,plasma decay,one of the thermal processes,can efficiently make neutrinos during this stage.Due to the high mass-loss rate,a star with a mass of 9 M⊙ does not undergo the helium flash.Its neutrinos mainly originate from nuclear reactions until the end of the AGB stage.At the end of the AGB stage,its neutrino luminosity results from plasma decay which is triggered by the gravitational energy release because of the stellar core contracting.
基金supported by the Natural Science Foundation of Hainan province (Grant No.114012)
文摘Based on the shell-model Monte Carlo method and random phase approximation theory, the neutrino energy spectrum (NES) and the electron capture (EC) of ^56Fe, ^56Co, ^56Ni, ^56Mn, ^56Cr and ^56V are investigated in presupemova surroundings. The results show that the EC rates are affected greatly at different densities and temperatures. The rates increase greatly and even exceed six orders of magnitude at lower temperature. On the other hand, the NES is very sensitive to stellar temperature and electron energy. The higher the temperature and the lower the electron energy, the larger the influence on NES is. For example, the maxima of NES in the ground state are 9.02, 160, 80, 24.01, 0.44, 1.42 me c^2 for ^56Fe, ^56Co, ^56Ni, ^56Mn, ^56Cr and ^56V respectively at ρ7 = 10.7, Ye = 0.45 and T9 = 15. Furthermore, the influence on NES due to EC for different nuclei has some otherness because of different Qo-values. For example, the spectrum of ^56Co shows a double bump structure.