Nuclear decay scheme studies of 30-h 131Te/sup m/, 25-min 131Te/sup g/, and 55.5-min 105Cd

High-resolution Ge(Li) detectors have been used to observe γ-ray singles and coincidence spectra of 30-h 11/2-, /sup 131m/Te, 25-min 3/2+, and 55.5-min 5/2+105Cd. Sources of /sup 131m/Te and /sup 131g/Te were produced by neutron irradiation of enriched 130Te metal, and, in the case of /sup 131m/Te, were chemically purified to remove the 131I daughter. A total of 190 and 80 γ-rays are attributed to the decays of /sup 131m/Te and /sup 131g/Te, respectively; and 174 and 77 of these transitions have been placed in a 131I level scheme involving 52 excited states. Absolute β group intensities were determined for the transitions to 131I levels. Spin and parity assignments were made for all observed levels. The β feeding from the 11/2- /sup 131m/Te to the 7/2+131I ground state was determined to be (5.2 +- 3.0) percent (log ft = 10.5). The isomeric transition of 11/2- /sup 131m/Te to 3/2+ /sup 131g/Te was determined to be (22.2 +- 1.6) percent. The 6-nsec isomer in 131I at 1797 keV has been assigned as 15/2- and interpreted as a πν1ν2 three quasi-particle state. Sources of 105Cd were produced via the 106Cd(n,2n) reaction on enriched 106CdO using 14 MeV neutrons. A total of 274 γ-rays are attributed to the decay of 105Cd, and 248 of these have been placed in a 105Ag level scheme involving 50 excited states. Absolute values for the β+/EC transition intensities to 105Ag levels were determined. The β+/EC feeding from the 5/2+105Cd to the 7/2+ 25.5-keV isomeric state in 105Ag was determined to be (51.4 +- 4.0) percent (log ft = 5.4). The experimentally determined level structures of 131I and 105Cd are interpreted in terms of the shell model and core excitation considerations with emphasis placed on the core coupling model and the three-particle models. (U.S.)