Levels inCr50,Cr52,Cr53, andCr54

Abstract

Inelastically scattered proton spectra from targets of natural chromium and targets enriched in ${\mathrm{Cr}}^{50}$, ${\mathrm{Cr}}^{53}$, and ${\mathrm{Cr}}^{54}$ have been studied for bombarding energies in the region of 4.3 to 4.6 Mev using a doublefocusing magnetic spectrometer, at angles of observation of 91.5° and 136.2°. The enriched targets were prepared by the vacuum evaporation of ${\mathrm{Cr}}_2$ ${\mathrm{O}}_3$ from a small carbon crucible mounted on a tungsten filament onto gold-leaf backings. Surveys were taken up to at least 2.0-Mev excitation. The following level energies in kev were determined: ${\mathrm{Cr}}^{50}$, 780±3; ${\mathrm{Cr}}^{52}$, 1432±5; ${\mathrm{Cr}}^{53}$, 562±3, 1006±4, and 1287±5; ${\mathrm{Cr}}^{54}$, 842±6. The new level in ${\mathrm{Cr}}^{50}$ occurs at the energy expected for the first 2+ state. Inelastically scattered proton groups corresponding to the known second excited states of ${\mathrm{Cr}}^{52}$ and ${\mathrm{Cr}}^{54}$ were not of sufficient intensity to be observed.