Speaker
Description
The synthesis of fluorine in a stellar environment remains an important topic in nuclear astrophysics. The nucleus $^{19}$F is believed to be produced in a side branch of the CNO cycle and in thermally pulsing asymptotic giant branch (AGB) stars through reactions such as the $^{15}$N($\alpha$,$\gamma$)$^{19}$F reaction. Spectroscopic information such as excitation energies, $\gamma$-widths, and lifetimes of states in $^{19}$F and its mirror partner $^{19}$Ne provides important information on astrophysical reaction rate calculations. However, in proton-rich stellar environments $^{19}$F can be quickly destroyed due to the huge cross section of the competing $^{19}$F(p,$\alpha$)$^{16}$O process. Consequently, accurate spectroscopic data on the excited states of $^{19}$F and its mirror partner $^{19}$Ne are crucial for nuclear inputs used in astrophysical reaction rate calculations. The nuclides were populated in heavy-ion induced reactions using a $^{9}$Be beam on an oxidized lead (PbO) target, at an incident energy of 37 MeV at the Tata Institute of Fundamental Research (TIFR), Mumbai Pelletron Linac Facility. De-exciting $\gamma$-rays were detected with HPGe clover detectors arranged at various angles with respect to the beam axis. Coincidence events were sorted into $\gamma - \gamma$ matrices and $\gamma - \gamma - \gamma$ cube using the MARCOS code and analyzed with the RADWARE and INGASORT software packages. In addition to confirming previously known transitions, three new $\gamma$-ray transitions have been identified. Doppler-broadened lineshapes of a few gamma ray transitions were observed, and lifetimes of a few selected states were extracted using the Doppler Shift Attenuation Method (DSAM). The mirror symmetry between $^{19}$F and $^{19}$Ne allows the extraction of spectroscopic properties relevant to reactions involving proton-rich nuclei in astrophysical environments.