Abstract
The beta spectrum of the main inner group of 89.0-hr ( kev; 24% of total betas; ) has been magnetically analyzed in coincidence with the 137.2-kev gamma. The observed spectrum does not have the allowed shape nor the unique (, yes) shape; its spectrum shape correction factor increases about 18% from 150 kev to 900 kev. Subtraction of this spectrum, weighted with its measured relative abundance, from the composite spectrum, produces the spectrum of the ground state transition ( kev; 76% of total betas; ). Its similarly nonallowed, nonunique shape factor increases by about 22% from 150 kev to 1050 kev. Both transitions are interpreted as first forbidden (, yes); is assigned a ground state spin and parity 1(-). A theoretical parametric fitting of these spectra with the combination of scalar and tensor beta interactions is demonstrated; the limited ranges of the fitting parameters, which are functions of the nuclear matrix elements, are obtained.
A comparison is presented between the theoretical fittings of the beta spectrum of the inner group and of the beta-gamma angular correlation.
Pursuant to these studies on we obtained values for the maximum beta energies, gamma energies, conversion coefficients, half-life, and branching ratios, particularly of the approximately 0.1% abundant 307-kev beta group.
- Received 9 January 1956
DOI:https://doi.org/10.1103/PhysRev.103.921
©1956 American Physical Society