Level and life-time studies in odd-odd $^{202,204}$Tl

The $^{203,205}$Tl($n,2n\gamma$) reactions were used to study excited states in odd-odd $^{202,204}$Tl isotopes. The data were taken using the GEANIE spectrometer, a Compton-suppressed array of 26 Ge detectors. The pulsed neutron source of the Los Alamos Neutron Science Center's WNR facility provided neutrons in the energy range from 0.6 to 250~MeV. The time-of-flight technique was used to determine the incident neutron energies. Partial $\gamma$-ray cross sections were measured from the beam-on data while half-lives of isomers were determined from the beam-off data (typically, the half-lifes that can be currently measured with GEANIE vary between a few $\mu$s to a few ms). The level schemes of $^{202,204}$Tl have been considerably enriched and extensive similarities observed between the two level schemes are discussed. The previously reported first excited state in $^{202}$Tl has been decomposed into two close-lying states. In $^{204}$Tl, the structure above the previously known 7$^{+}$ isomer (from the $\pi s_{1/2} \nu i_{13/2}$ configuration) at 1104-keV excitation energy has been established for the first time up to $E_{x} \sim$2.3~MeV, while, at higher excitation energies, a lower limit for the excitation energy of the $\pi h_{11/2} \nu i_{13/2}$ configuration is proposed. The half-lives of the 7$^{+}$ isomers of $^{202,204}$Tl were measured with more precise results than the values adopted in the literature. This work was supported by the U.S. Department of Energy under Contracts No. DE-AC52-06NA25396 (LANL) and DE-AC52-07NA27344 (LLNL).