Internal decay of the (10) intruder state in Tl

Van Beveren, C.*; Andreyev, A. N.; Barzakh, A.*; Cocolios, T. E.*; Fedorov, D.*; Fedosseev, V. N.*; Ferrer, R.*; Huyse, M.*; Kster, U.*; Lane, J. F. W.*; Liberati, V.*; Lynch, K. M.*; Marsh, B. A.*; Procter, T. J.*; Radulov, D.*; Rapisarda, E.*; Sandhu, K.*; Seliverstov, M. D.*; Van Duppen, P.*; Venhart, M.*; Veselsky, M.*

Decay spectroscopy of Tl has been performed at the CERN Isotope Separator On-Line (ISOLDE) facility. An excitation energy of 506.1(1) keV and a half-life of 47.1(7) ms of the intruder based (10) state have been extracted. The internal decay characteristics of this state are determined and discussed, extending the systematics of such states in the even-mass thallium nuclei below neutron midshell at N = 104. The retardation factors of the isomeric M2 and E3 transitions are deduced and compared with retardation factors in neighboring odd-mass and even-mass thallium isotopes. The new information is combined with a review of hindered and unhindered -decay data of Bi populating levels in daughter nuclei Tl and supports the interpretation of the intruder character of the (10) state in Tl.