52Cr Reaction Research Articles

Calculations and analysis of n+52Cr reactions below 20 MeV

ABSTRACT Chromium is one of the important structural materials in the process of nuclear reaction, and the precise nuclear data of n + 52Cr reaction is very important. On the basis of the spherical optical model, the unified Hauser–Feshbach theory and exciton model, all reaction cross sections, angular distributions, energy spectra, and double-differential cross sections were calculated and analysed for n + 52Cr reactions below 20 MeV. The theoretical calculations were compared with the available experimental data and other evaluation data from ENDF/B-VIII.0 and JENDL-5.

Cross sections of 56Fe(n, p)56Mn, 55Mn(n, p)55Cr, 52Cr(n, p)52V, 56Fe(n, α)53Cr, 55Mn(n, α)52V and 52Cr(n, α)49Ti reactions using phenomenological level density models from threshold to 20 MeV

56Fe(n,p)56Mn, 55Mn(n,p)55Cr, 52Cr(n,p)52V, 56Fe(n, α)53Cr, 55Mn(n, α)52V and 52Cr(n, α)49Ti reactions are evaluated using four phenomenological nuclear level density models from reaction threshold to 20 MeV. The calculated data is compared with the experimental nuclear reaction data from EXFOR database. Statistical factors H, D and R are computed to identify the best fit. Level density parameters are adjusted for further improvement of the fitting. Back shifted Farmi-gas model gives a resemblance of neutron-induced 56Fe, 55Mn and constant temperature Fermi-gas model gives a closeness for 52Cr reaction with our new parameter values.

Channel cross correlation and intermediate resonance in the 55Mn(p,p)55Mn and 55Mn(p, alpha )52Cr reactions.

The excitation functions for the \ensuremath{\alpha} particles and protons from the reactions $^{55}\mathrm{Mn}$(p,p${)}^{55}$Mn and $^{55}\mathrm{Mn}$(p,\ensuremath{\alpha}${)}^{52}$Cr were measured from ${E}_{\mathrm{p}=5.8}$ to 7.0 MeV at ${\ensuremath{\theta}}_{\mathrm{lab}}$=90\ifmmode^\circ\else\textdegree\fi{}, 125\ifmmode^\circ\else\textdegree\fi{}, and 160\ifmmode^\circ\else\textdegree\fi{}. The cross sections were analyzed by the channel cross correlation function, the autocorrelation function, and the statistical compound nuclear theory of Feshbach to determine the number of correlating channels ${n}_{d}$, the average total level width 〈${\ensuremath{\Gamma}}_{\ensuremath{\mu}}$〉, and the ratio 〈${\ensuremath{\Gamma}}_{\ensuremath{\mu}}$〉/D. With these values, the theoretical intermediate width 〈${\ensuremath{\Gamma}}_{d}$\ensuremath{\uparrow}〉 was calculated to be 27\ifmmode\pm\else\textpm\fi{}11.7 keV, which was consistent with the experimental result 36\ifmmode\pm\else\textpm\fi{}8 keV within the errors. The ratio ${n}_{d}$(${n}_{d}$-1)/${n}^{2}$ was determined to be 0.63\ifmmode\pm\else\textpm\fi{}0.16, which was also in agreement with the theoretical prediction (2D/\ensuremath{\pi}〈${\ensuremath{\Gamma}}_{\ensuremath{\mu}}$${〉}^{1/2}$=0.40\ifmmode\pm\else\textpm\fi{}0.0 9, within the error.

An investigation of the importance of multi-step processes in the three-nucleon (p, α) transfer reactions

DWBA calculations were carried out using one-step and two-step processes that included both sequential transfer and inelastic transfer processes in the three-nucleon (p, α) transfer reaction. A comparison of the theoretical calculations with our previously presented data of the 56Fe(p, α) 53Mn and 55Mn(p, α) 52Cr reactions at 35 MeV indicates the importance of the two-step (p, α')(α', α) and (p, t)(t, α) process in some weak direct (p, α) transitions. However, for the strong (p, α) transitions in the reaction 92 Zr( p, α) 89 Y at 35 MeV the two-step contributions are very small.

Effect of neutron excitations on the strength distributions for single-proton transfer reactions on the N = 28 nuclei

Strong fragmentation of the proton 2 p 3 2 spectroscopic strengths, observed in the 51V( 3He, d) 52Cr reactions in the exci energy range of 3 to 8 MeV, can be explained introducing the basis functions which involve neutron excitations from the N = 28 closed shell in the shell-model wave functions.

The50V(α, d)52Cr reaction at 14 MeV and theJ π=8+ level of52Cr

The50V(α, d)52Cr reaction at 14 MeV and theJ π=8+ level of52Cr

A study of the nucleus 52Cr using the 51V(τ, d) 52Cr reaction at 15 MeV

Angular distributions of the (τ, d) and (τ, τ) reactions on 51V have been measured at E τ = 15 MeV using a multichannel magnetic spectrograph. Optical model parameters have been obtained from an analysis of the elastic scattering. These parameters have been used to calculate theoretical angular distributions using the DWBA. Spectroscopic factors and l p values for 52Cr levels up to E x = 8.4 MeV were obtained by comparison of the data with the DWBA theory. Many levels due to l p = 0, 1, 3 and 1 + 3 transfers not previously seen in proton stripping reactions are reported. The Spectroscopic information obtained is compared with that from other reactions leading to 52Cr. This has enabled tentative suggestions to be made concerning the wave functions of several of the states. A comparison is also made with the available theoretical calculations and it is concluded that further calculations are required using a much larger configuration space and possibly core excitations.

Alpha capture to the giant dipole resonances of 42Ca, 44Ca and 52Cr

Differential cross sections for the 38 Ar(α, γ 0) 42 Ca, 40 Ar(α, γ 0, 1) 44 Ca and 48 Ti(α, γ 0, 1) 52 Cr reactions were measured at 90° to the beam direction in 50 or 100 keV steps over the bombarding energy ranges 6.0–15.0 MeV, 5.5–11.1 MeV and 6.0–12.0 MeV respectively. Gamma-ray angular distributions were measured at forty bombarding energies. These show that the ( α, γ 0) reaction proceeds through 1 − levels and to a lesser extent 2 + levels, whereas the ( α, γ 1) reaction most probably proceeds through 1 − and 3 − levels. It is deduced that 〈 Γ〉/〈 D〉 ≦ 1 for the 40Ar( α, γ) 44Ca. reaction whereas the fine structure observed in the 48Ti( α, γ) 52Cr reaction is probably due to fluctuations. From a comparison with other data it is shown that the (α, γ) reaction is most probably statistical in nature. Using Hauser-Feshbach theory it is deduced that the 36Ar( α, γ) 40Ca. reaction is inhibited by isospin selection rules and an estimate is made of isospin mixing in the 40Ca giant dipole resonance. The 38 Ar(α, γ) 2 42 Ca and 40 Ar(α, γ) 44 Ca data are considered with respect to theories of isosopin splitting of the giant dipole resonance.

Analogue resonances of low lying levels of52V in the51V(p,γ)52Cr reaction

The analogues of the 52V levels at 0.793 and 0.846 MeV have been examined as resonances in the 51V (p, gamma )52Cr reaction at proton energies of 1.567 and 1.629 MeV. The resonance at 1.567 MeV and hence the 0.793 MeV 52V level has been assigned Jpi of 3+ and the most probable Jpi value for the 1.629 MeV resonance and hence the 0.846 MeV 52V level is shown to be 4+. These results are consistent with previous theoretical calculations of the 52V levels.

Isobaric analogue resonances of the 51V(p, γ) 52Cr reaction

In the excitation curve of the 51V(p, γ) 52Cr reaction, 11 isobaric analogue resonances have been observed corresponding to low-lying states of 52V. Some of the analogue resonances are seen to have a certain structure which is reminiscent of the Robson theory of asymmetrically enhanced fluctuations.