Gamma-Ray Decay of the Low-Lying Levels ofF21

The ${\mathrm{F}}^{19}(t, p\gamma ){\mathrm{F}}^{21}$ reaction at triton energies near 3 MeV was used to study the $\gamma$-ray decay of the first six energy levels of ${\mathrm{F}}^{21}$. $\gamma$-ray decay modes and Doppler-shift information was obtained from proton-$\gamma$ coincidence measurements. Some excitation energies were obtained from singles measurements, as well as the coincidence studies. Excitation energies (in keV) and lifetimes (in psec) for the first six levels are 279.92±0.06, 8800±330; 1100.9±2.0, 0.44±0.08; 1729.6±1.0, 0.07±0.06; 1754.9±0.7, >1.5; 2040.0±2.0, <0.05; and 2070.9±2.0, 0.08±0.03. Some information was also obtained on the $\gamma$-ray branching of higher states.