Gamma Rays from the Low-Lying Levels ofF18

Abstract

A 5-mm-thick lithium-drifted germanium counter was used to detect the low-energy gamma rays ($E\gamma <1.8\mathrm{}$ MeV) emitted at 90° to the beam following bombardment of an ${\mathrm{O}}^{16}$ gas target with ${\mathrm{He}}^3$ ions with a mean energy of 1.8 MeV. The excitation energies of the first seven levels of ${\mathrm{F}}^{18}$ were determined to ±2 keV or better from energy measurements of the de-excitation gamma rays from these levels. The decay of the ${\mathrm{F}}^{18}$ 2.10-MeV level to the 0.94- and 1.08-MeV levels was confirmed, and an upper limit of 6% was placed on the branch to the 1.045-MeV level.