Calculation of Photonuclear Data for ~(180,182,183,184,186)W

Based on available experimental data of neutron and photonuclear reaction, a set of neutron optical potential parameter and giant resonance parameters of γ for W were obtained. The photonuclear reaction data for ~(180,182,183,184,186)W were calculated and compared with experimental data.     

The Sub-Library of Giant Dipole Resonance Parameters for γ-Ray (CENPL-GDP-1)

The data file and management-retrieval code system of the giant dipole resonance parameter sub-library (CENPL-GDR) are described. Because there are no giant dipole resonance parameters obtained from the experimental data for many nuclei, a treatment method in the management-retrieval code system was presented. Some problem on the giant dipole parameters are discussed in the report.     

Evaluation and Calculation of Photonuclear Reaction Data for ~(209)Bi below 30 MeV

Based on available experimental data of neutron and photonuclear reaction,both neutron optical potential parameter and giant resonance parameters of gamma for ~(209)Bi were obtained. The photonuclear reaction data for ~(209)Bi were calculated, compared with experimental data and recommended below 30 MeV.     

Simulation and test of the SLEGS TOF spectrometer at SSRF

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 LaBr3detectors. Geant4 was used to sim...     

Calculations of the Gamma Energy Spectra from Neutron Radiative Capture Reactions for ~(197)Au

The aim of this paper is to theoretically explain the abnormal protuberances near and above 5.5 MeV in the gamma spectra of the (n,γ) reactions of the nuclei within the nuclear mass regions from 110 to 140 and from 180 to 210, respectively. Supposing that in the primary and cascade gamma de-excitation processes of the compound nucleus, in addition to the giant dipole resonance model, there exist the de-excitation processes of the excited states of ~6He, ~6Li, ~6Be, ~7Li and ~7Be particle cliques, for which the gamma-ray strength function was developed. The (n,γ)reaction cross sections and the gamma energy spectra at the neutron incident energies from 0.01 MeV to 3 MeV for ~(197)Au were calculated and the results are in better coincidence with the experimental data. Especially for the gamma energy spectra, the abnormal protuberances near and above 5.5 MeV were reproduced very well.     

THE EVALUATION OF~(59)Co(n,γ)~(60)Co REACTION CROSS SECTION AND ITS COVARIANCE DATA

~(59)Co(n,γ)~(60)Co reaction cross section is of importance for dosimetry appli-cation.The evaluation and its covariance for ENDF/B-V were performed byS.Mughabghab in 1977.Since then,there are no any newly measured data.Al-though the resonance parameters measured by Spencer et al. was publishedbefore that of the evaluation for ENDF/B-V,only the data in the unresolvedresonance region measured by Spencer and Macklin were adopted in theevaluation for BNL-325.The present evaluation including the covariance isalso carried out based on the same data body.     

Evaluation of Cross Sections for ~(197)Au(n,3n) and ~(197)Au(n,4n) Reactions from Threshold to 50 MeV

The measured data of cross sections for ~(197)Au(n,3n) and ~(197)Au(n,4n) reactions were collected and analysed. The theoretical calculations of above mentioned reactions were carried out to predict the data in higher energy region. The sets of cross sections for ~(197)Au(n,3n) and ~(197)Au(n,4n) reactions from threshold to 50 MeV were recommended on the basis of the experimental and calculated data.     

Evaluation of Cross Sections of Photonuclear Reactions for ~(90,91,92,94,96)Zr Below 30 MeV

The study of the properties of nuclei near to the closed neutron shell at N=50 is a subject of widespread interest. The accurate photonuclear data play an important role in nuclear science and technology. In this work, the experimental data of photonuclear up to 30 MeV for ~(90,91,92,94,96)Zr were evaluated which is impotant to radiation damage, radiation safety, reactor dosimetry. The theoretical calculation were used for supplement to some energy where the measured photonuclear data are scarce. The recommended photonuclear data for ~(90,91,92,94,96)Zr were obtained based on evaluated and calculated data and compared with existing measured data.     

The Calculations of Photonuclear Data

The photonuclear reaction data with the approximate energies up to 30 MeV have been calculated. The formulations are described. The photonuclear reactions include the scattering, absorption and particle production of photons induced on nuclei. For example, the photonuclear data of ~(27)Al, ~(54)Fe and ~(209)Bi were calculated and compared with experimental data.     

Progress on Chinese Evaluated Nuclear Parameter Library (Ⅴ)

A new edition of MCC-1.1 (1995 Version) sub-library has been completed. It contains the atomic mass data for 4771 nuclides ranging from Z=0, A=1 to Z=122, A=328, including the measured and systematics mass excesses, atomic masses and total binding energies for 2650 nuclides compiled and recommended by Audi and Wapstra in 1993 and mass excesses of 2121 nuclides calculated by Moller et al. in 1994. A few of them (181 nuclides)     

Tests of the GIC and Measurements of Angular Distributions and Energy Spectra for ~(58)Ni(n,p)~(58)Co Reaction at 4.1 MeV

On the basis of measurements of double differential cross sections for (n,α) reactions in 5-7 MeV neutron energy region using gridded ionization chamber (GIC), we constructed a new GIC which, compared with the old ones, can bear higher pressure and makes it possible to measure (n,p) reactions up to 6 MeV and (n,xα) reactions up to 20 MeV. To test the new chamber, the saturation property for argon and krypton mixed with a few percent CO_2 was studied using ~(241)Am and compound Pu α source and tritium from ~6Li(n_(th),t)~4He, and the two dimensional spectra for ~(241)Am and Pu α source, ~6Li(n_(th),t)~4He and H(n,p) reactions were measured. The measured energy spectra and angular distributions for α and tritium are reasonable, and the derived data for α, proton and tritium in argon and krypton from the measured spectra data were compared with the calculated ones. They are in good agreement. The angular distributions and energy spectra for ~(58)Ni(n,p)~(58)Co reaction at 4.1 MeV neutron energy were m     

Soft Giant Dipole Modes in Ca Isotopes in the Relativistic RPA

The purpose of this work is to apply the fully consistent RRPA method to the collective giant resonance of nuclei far from the p-stability line. The isovector giant dipole resonance in Ca isotopes is investigated in the framework of the fully consistent RRPA. The calculations are performed in an effective Lagrangian with a parameter set NL3, which was proposed for satisfactorily describing nuclear ground state properties as well as the isospin giant monopole resonance, i.e. nuclear breathing mode. The response functions of IVGDR for various Ca isotopes are plotted in Fig.1. The solid and dotted curves are full RRPA and unperturbed strengths, respectively. The dashed curves represent the     

Sub-library of Updated Fission Barrier Parameters(CENPL-FBP2)

The fission barrier parameters are important to determine the fission character of a nucleus. The fission barrier parameters and fission level densities are key ingredients in calculations of not only fission cross section but also various cross sections, and spectra for the fissile nuclides, even heavy nuclides at higher incident energies. It is necessaries that the accuracy of fission barrier parameters requires even higher, and nuclides with fission barrier parameters can cover even wider nuclear range.     

Indirect Measurement of 58 keV Resonance of ~(25)Mg(p,γ)~(26)Al via(~7Li,~6He)Reaction

正~(25)Mg(p,γ)~(26)Al is one of the key reactions for Mg-Al cycle in explosive hydrogen burning of stars.Its cross sections at star energies are essential to understand the problem of ~(26)Al and ~(26)Mg abundances.It is very difficult to direct measure the 58 keV resonance in ~(25)Mg(p,γ)~(26)Al reaction.Because of the interference of the     

Theoretical Calculation of n ~(59)Co Reaction in Energy Region up to 100 MeV

A set of neutron optical potential parameters for ~(59)Co in energy region of 2～100 MeV was obtained based on concerned experimental data. Various cross sections of n ~(59)Co reactions were calculated and predicted. The calculated results show that the activation products ~(58,57)Co, ~(59)Fe, and ~(56)Mn are main neutron monitor reaction products for n ~(59)Co reaction in energy range up to 100 MeV. ~(54)Mn production reaction can be a promising neutron monitor reaction in the energy region from 30 to 100 MeV.     

The cross section calculation of ~(112)Sn(α,γ) ~(116)Te reaction with different nuclear models at the astrophysical energy range

The theoretical cross section calculations for the astrophysical p process are needed because most of the related reactions are technically very difficult to be measured in the laboratory. Even if the reaction was measured,most of the measured reactions have been carried out at the higher energy range from the astrophysical energies.Therefore, almost all cross sections needed for p process simulation have to be theoretically calculated or extrapolated to the astrophysical energies.~(112)Sn(α,γ)~(116)Te is an important reaction for the p process nucleosynthesis. The theoretical cross section of ~(112)Sn(α,γ)~(116)Te reaction was investigated for different global optical model potentials,level density, and strength function models at the astrophysically interested energies. Astrophysical S factors were calculated and compared with experimental data available in the EXFOR database. The calculation with the optical model potential of the dispersive model by Demetriou et al., and the back-shifted Fermi gas level density model and Brink-Axel Lorentzian strength function model best served to reproduce experimental results at an astrophysically relevant energy region. The reaction rates were calculated with these model parameters at the p process temperature and compared with the current version of the reaction rate library Reaclib and Starlib.     

The Evaluations of ~(59)Co and ~(55)Mn Neutron Data from 10~(-5) eV to 20 MeV

The evaluated data are given in ENDF/B-4 format.They include thermalneutron cross sections,resonance parameters,fast neutron cross sections,anglardistributions and energy distributions of secondary neutrons.The experimentaldata are used up to the end of 1985 for ~(59)Co and up to the beginning of 1988for ~(55)Mn.The data are obtained from the nuclear model calculations when the     

Atomic Mass and Characteristic Constant of Nuclear Ground State (CENPL.MCC) (Ⅰ)

Atomic mass and characteristic constants for nuclear ground states are basic data for nuclear physics, and necessary ones for basic researches, theoretical calculations, as well as many applied researches. The atomic mass of exotic nuclei quite far from the valley stability are also very important for astrophysics researches. The above-requirement is paid attention to in our setting up this file. The recent and as many as possible data (such as the half-lives of the new nuclides ~(202)Pt, ~(208)Hg and ~(185)Hf and the mass excess of ~(199)Ir, which were produced and distinguished by Chinese scientists ) have been collected, and put into the computer-based data file in brief table format.     

Response of multi-step compound pre-equilibrium reaction cross sections for the (p,n) reactions to forms of optical model parameters

In furtherance to improving agreement between calculated and experimental nuclear data, the nuclear reaction code GAMME was used to calculate the multistep compound(MSC) nucleus double differential cross sections(DDCs) for proton-induced neutron emission reactions using the Feshbach-Kerman-Koonin(FKK) formalism. The cross sections were obtained for reactor structural materials involving ~(52)Cr(p, n)~(52)Mn,~(56)Fe(p,n)~(56)Co, and ~(60)Ni(p, n)~(60)Cu reactions at 22.2 MeV incident energy using the zero-range reaction mechanism. Effective residual interaction strength was 28 MeV, and different optical potential parameters were used for the entrance and exit channels of the proton-neutron interactions. The calculated DDCs were fitted to experimental data at the same backward angle of 150°, where the MSC processes dominate. The calculated and experimental data agree well in the region of pre-equilibrium(MSC) reaction dominance against a weaker fit at the lower emission energies. We attribute underestimations to contributions from the other reaction channels and disagreement at higher outgoing energies to reactions to collectively excited states. Contrary to the FKK multi-step direct calculations, contributions from the higher stages to the DDCs are significant. Different sets of parameters resulted in varying levels of agreement of calculated and experimental data for the considered nuclei.     

Evaluation of Activation Cross Sections for Fission Product Nuclides of ~(140,141,142,144)Ce below 20 MeV

The activation cross sections were evaluated for fission product nuclides of ~(144,141,142,144)Ce below 20 MeV to provide data for reactor design. Evaluation was made on the basis of experimental data up to 1998 and nuclear mode calculation. The experimental data for ~(140,142)Ce(n, 2n), ~(140,142)Ce(n,γ) from threshold energy to 20 MeV and ~(140,142)Ce(n, p), ~(142)Ce(n,α)reactions at some energys points were adopted in this work. The evaluated data of ~(140,141,142,144)Ce were compared with other evaluated data from ENDF/B-6, JENDL-3 and BROND-2 Libraries.