共查询到8条相似文献,搜索用时 0 毫秒
1.
The (n, α) reaction cross-sections from threshold to ∼20 MeV on some important nuclides 42Ca, 50,53Cr, 56,57Fe, 58,62Ni, and 63,65Cu involved in the reactor shielding design have been calculated using the Hauser–Feshbach statistical model with preequilibrium effects by involving PCROSS option in Empire 2.19. The transmission coefficients for neutrons in the entrance channel are calculated using the optical model potential of Koning. In the exit channel optical model potential of Avrigeanu has been used. The experimental values have been chosen carefully for all the isotopes, from EXFOR data base. The calculations are compared with existing experimental data as well as with evaluated data files (ENDF/B-VI.0 and JENDL-3.3). A good agreement between the calculated and experimental data validates the nuclear model approaches with increased predictive power to supplement and extend the nuclear database that is required for several applications. 相似文献
2.
The cross sections for the 175Lu(n, α)172Tm, 176Lu(n, α)173Tm and 175Lu(n, p)175m+gYb reactions have been measured in the neutron energy range of 13.5–14.8 MeV using the activation technique. The first data for 175Lu(n, α)172Tm reaction cross sections are presented. In our experiment, the fast neutrons were produced via the 3H(d, n)4He reaction on K-400 Neutron Generator at Chinese Academy of Engineering Physics (CAEP). Induced gamma activities were measured by a high-resolution (1.69 keV at 1332 keV for 60Co) gamma-ray spectrometer with high-purity germanium (HPGe) detector. Measurements were corrected for gamma-ray attenuations, random coincidence (pile-up), dead time and fluctuation of neutron flux. The neutron fluences were determined by the cross section of 93Nb(n, 2n)92mNb or 27Al(n, α)24Na reactions. The neutron energy in the measurement was by the cross section ratios of 90Zr(n, 2n)89m+gZr and 93Nb(n, 2n)92mNb reactions. The results were discussed and compared with experimental data found in the literature and with results of published empirical formulae. 相似文献
3.
Accurate measurements have been made to determine radiation transmission of concretes produced with barite, colemanite and normal aggregate by using beam transmission method for 0.663 MeV γ-rays energy of 137Cs radioactive isotopes by using NaI(Tl) scintillation detector. Linear and mass attenuation coefficients of thirteen heavy- and four normal-weight concretes were calculated. It was determined that the linear attenuation coefficient (μ, cm−1) decreased with colemanite concentration and increased with barite concentration in both type of the concretes. Mass attenuation coefficient values of our concretes were compared with the values proposed by the United States National Institute of Standards and Technology (NIST). 相似文献
4.
Pritty RaoSanjiv Kumar S. VikramkumarV.S. Raju 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2011,269(21):2557-2562
The paper reports the widths and differential cross-sections of resonances at 3.089, 3.379 and 3.717 MeV in the 32S(p,p′γ)32S nuclear reaction. The cross-sections are computed at 0° and 90° angles (relative to the beam direction) from thick target excitation curves constructed by measuring 2230 keV γ-rays, characteristic of the reaction. The differential cross-sections of resonances are about 18, 64 and 70 mb/sr respectively at 0° angle and decrease by about half around an angle of 90°. The first resonance, the sharpest among the three, exhibits a width of about 400 eV while those at 3.379 and 3.717 MeV are in 1.0-1.5 keV range. The widths of the resonances are extracted from the respective thick target excitation curves by an interquartile separation method and also by simulating their leading edges. A study of thick target yields in the 3.0-4.0 MeV proton energy region for several sulphide forming elements shows the absence of any significant interference. These resonances, as a result, can be effectively utilised for sensitive and high resolution depth profile measurements of sulphur in films and materials surfaces. 相似文献
5.
E.P. Ivanova 《Atomic Data and Nuclear Data Tables》2009,95(6):786-804
Relativistic perturbation theory with a model potential is used for the calculation of energy levels of the states 4f5/2, 4f7/2, 5s1/2, 5p1/2, 5p3/2, 5d3/2, 5d5/2, 5f5/2, and 5f7/2 above the 1s22s22p63s23p63d104s24p64d10 core, with one vacancy , in the same core, in the silver and rhodium isoelectronic sequences with the maximum nuclear charge Z = 86. The method of extrapolation of the model potential parameter is applied to calculate one-electron and one-vacancy wavefunctions. The wavefunctions of Ag- and Rh-like ions were used to calculate the energies of resonance transitions to the ground state 1S0 in Pd-like ions. Good agreement between the theoretical and the experimental energies of the resonance transitions in Pd-like ions indicates the reliability of the results obtained. 相似文献
6.
Junhua Luo Fei Tuo Xiangzhong Kong 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2008,266(22):4862-4868
Three new semi-empirical formulae for the calculation of the (n,α), (n,p) and (n,2n) cross-sections at neutron energy 14.5 MeV were obtained on the basis of experimental data measured by Lanzhou University. Derived from the statistical model with consideration of the Q-value dependence, the new formulae include three, three and four parameters for (n,α), (n,p) and (n,2n) reactions, respectively. The obtained relations are compared with other recently proposed systematics based on the statistical model as well as on the asymmetry parameter dependence. 相似文献
7.
Changlin Lan Xiaosan Xu Kaihong Fang Gang Liu Xiangzhong Kong Rong Liu Li Jiang 《Annals of Nuclear Energy》2008
Activation cross sections at the neutron energy about 14 MeV on germanium isotopes have been measured, employing the activation technique and γ-ray spectrometry. The data of the cross section are reported for the (n, 2n), (n, p) and (n, α) reactions. The neutron flux was determined using the monitor reactions 27Al (n, α) 24Na and the neutron energies were measured by the method of cross section ratios for 90Zr (n, 2n) 89Zr to 93Nb (n, 2n) 92mNb reactions. The measured results were compared with the other measurements. 相似文献
8.
《Annals of Nuclear Energy》2002,29(17):2019-2027
Cross sections were measured at neutron energies from 13.6 to 14.9 MeV for the reactions 23Na(n,p)23Ne and 23Na(n,α)20F, and 26Mg(n,p)26Na leading to short-lived products. The production of short-lived nuclei and the spectra accumulation have been carried out by cyclic activation method. Corrections were made for the effects of gamma ray attenuation, coincidence summing, pulse pile-up, dead time, neutron flux fluctuations and scattered low energy neutrons. 相似文献