title: Electron-gamma spectroscopic measurements in 131 Cs.
abstract: The decay of 131 Ba to levels of 131 Cs has been studied using an HPGe detector for gamma-ray and a mini-orange electron spectrometer for conversion electron measurements. Our experiment identifies 76 gamma transitions in this decay, including 15 new gamma rays and 6 new K-conversion electron lines. The results also include M2 multipolarity assignment for the 269 keV transition, E2 assignment to two newly observed transitions, M1 + E2 for the 406 and 417 keV transitions and M3 for the 533.67 keV transition. A revised 131 Cs level scheme is proposed. While confirming the existence of 15 well-established levels, we present strong evidence from our beta decay study for five levels at 496, 764, 775, 1044 and 1258 keV which were earlier observed in reaction studies. Spin-parity assignments to a few other levels are also suggested. The level structure of 131 Cs is discussed in the light of the intermediate coupling model.
authors.affiliation: Department of Physics, Sri Sathya Sai University, Prasanthi Nilayam, 515 134, India.
authors.forename: Dwaraka Rani
authors.initials: DR
authors.lastname: Rao
authors.forename: K Vijay
authors.initials: KV
authors.lastname: Sai
authors.forename: M
authors.initials: M
authors.lastname: Sainath
authors.forename: R
authors.initials: R
authors.lastname: Gowrishankar
authors.forename: K
authors.initials: K
authors.lastname: Venkataramaniah