Abstract
The decay of and has been investigated with the aid of beta-ray spectrometer and coincidence measurements. From the half-life 20.7±0.3 min and the ratio 3.7±0.4, the 155±1-kev isomeric transition in is identified as . The 14.5±1-min ground state emits an allowed negatron spectrum of 656±6 kev and an allowed positron spectrum of 1.52±0.05 Mev. Even parity and spins of 4 and 1 are assigned to the two states. The 66-min ground state of decays by emission of an allowed positron spectrum of 2.25±0.02 Mev to the 657-kev level of . The electron capture from the isomeric state is followed by the known 884, 937, and 657-kev gamma-rays in . Even parity is assigned to both levels. Conversion lines, with indicate an additional gamma-ray of 121 kev which may be the isomeric transition having a branching ratio of about 0.6 percent. It would have to be an transition with an abnormally long (factor ) half-life. The existence of the isomer is shown to remove several difficulties in the interpretation of the excitation curves of the alpha-particle reactions with silver.
- Received 19 January 1953
DOI:https://doi.org/10.1103/PhysRev.90.464
©1953 American Physical Society