Abstract
The positron spectrum of has been investigated with two iron-free magnetic spectrometers. One measurement, performed with an intermediate-image spectrometer and a solid source, gave an end-point energy of 1.723±0.005 Mev. The other measurement, performed with a thin-lens spectrometer and a gaseous source, gave an end-point energy of 1.736±0.010 Mev. These values, which are approximately 0.050 Mev higher than the only previously reported spectrometer measurement, are in good agreement with the end point predicted from threshold determinations. The value calculated from an average end-point energy of 1.733±0.005 Mev derived from the beta spectra and the () threshold measurements is 4280±100 seconds. This new value brings the decay into good agreement with the analysis of the 0-0 spin change and the "doubly closed shell plus or minus one nucleon" beta transitions.
- Received 8 November 1956
DOI:https://doi.org/10.1103/PhysRev.105.1339
©1957 American Physical Society