| Popis: |
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\ifmmode^\circ\else\textdegree\fi{} and 136.2\ifmmode^\circ\else\textdegree\fi{}. 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\ifmmode\pm\else\textpm\fi{}3; ${\mathrm{Cr}}^{52}$, 1432\ifmmode\pm\else\textpm\fi{}5; ${\mathrm{Cr}}^{53}$, 562\ifmmode\pm\else\textpm\fi{}3, 1006\ifmmode\pm\else\textpm\fi{}4, and 1287\ifmmode\pm\else\textpm\fi{}5; ${\mathrm{Cr}}^{54}$, 842\ifmmode\pm\else\textpm\fi{}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. |
