(He3,d) Reaction on theN=28Nuclei

Abstract

A beam of 22-MeV ${\mathrm{He}}^3$ ions from the Los Alamos variable-energy cyclotron was used to investigate the (${\mathrm{He}}^3$, $d$) reaction on ${\mathrm{Ca}}^{48}$, ${\mathrm{V}}^{51}$, ${\mathrm{Cr}}^{52}$, and ${\mathrm{Fe}}^{54}$. A semiconductor $E-\Delta E$ mass-identification detector system was employed. The use of a summing preamplifier for performing the coherent addition of the $E$ and $\Delta E$ pulses allowed the energy resolution to be reduced to the inherent energy spread of the cyclotron beam, which is 100 to 120 keV. Levels or groups of levels were resolvable up to an excitation of 5 to 6 MeV for all the nuclei that were studied, and angular distributions were obtained for the deuterons corresponding to these levels. The t-sally distorted-wave calculation was used to extract spectroscopic information concerning the levels. The formalism developed by Macfarlane and French for the $j-j$ coupling version of the nuclear shell model was used to assign the levels to the $1f_{\frac{7}{2}}$, $1f_{\frac{5}{2}}$, $2p_{\frac{3}{2}}$, $2p_{\frac{1}{2}}$, and $1g_{\frac{9}{2}}$ single-particle states. Estimates of the positions of the centroids for the $T=T_z$ component of these single-particle states were made. The seniority mixing of the two $4^{+}$ states in ${\mathrm{Cr}}^{52}$ belonging to the ${\left(f_{\frac{7}{2}}\right)}^4$ configuration was determined and compares favorably with the predictions made by Komoda.