αdecay and recoil decay tagging studies ofTl183

Abstract

High-spin states in the nucleus 183 Tl have been studied using the recoil decay tagging and recoil tagging techniques. The data have enabled new structures to be identified which are believed to be based on prolate f 7/2 , h 9/2 , and oblate h 9/2 configurations. In addition, the prolate i 3/2 structure has also been extended. The systematics of the newly identified structures will be discussed. The ␣ decay of 183 Tl has also been investigated. Examination of both delayed and prompt ␥ rays in coincidence with the prominent 6333-keV ␣ decay, together with an investigation of the effects of the summing of L electrons, allow assignment of transitions and the construction of tentative low-spin decay schemes for 179 Au and 175 Ir.

Band structures and intruderπi13/2state in197Tl

“…The decay pattern of the former 13/2 + state in 197 Tl is quite similar (a strong E1 transition to the h 9/2 band) to the observed decay pattern of the πi 13/2 states in the lighter Tl isotopes [6,8,9,19,20]. Therefore, the 13/2 + state at 1553 keV in 197 Tl seems to be a candidate for the π [606]13/2 + "intruder" configuration.…”

Identification of intruderπi13/2state in197Tl

“…Moreover, the J π of the 1953-and 1867-keV states have also been modified from the previous assignments [3] based on the preliminary assignment of multipolarity and transition type for the 958-and 871-keV γ rays. Out of the two 13/2 + states at 1553 keV and 1953 keV, observed in our work, the former one has been proposed to be the candidate for the intruder πi 13/2 configuration due to its strong decay to the 11/2 − state of the πh 9/2 band similar to those observed for the lighter isotopes [1,8]. No band structure has been observed based on this state.…”

Detailed α -decay study of Tl180

“…Reduced α-decay widths, δ 2 α , deduced in our study, for the five highest-energy decays of 180 Tl (calculated using the Rasmussen approach [36], assuming L = 0 transitions) are listed in Table VI. All transitions have δ 2 α 5 keV, which means they are hindered compared to unhindered decays of neighboring isotopes, e.g., 179g,179m Tl with δ 2 α values of 50(3) and 89(4) keV [37,38] or 183 Tl with δ 2 α = 41(6) keV [39]. When compared to the average of quoted values, the δ 2 α value for the highest-energy transition of 180 Tl (6553 keV) yields a hindrance factor of ≈ 400.…”