A Measurement of the ft-Value of the Beta Decay of 0¹⁴

Citation

Bardin, Russell Keith (1961) A Measurement of the ft-Value of the Beta Decay of 0¹⁴. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/F97G-BY61. https://resolver.caltech.edu/CaltechETD:etd-03172006-091128

Abstract

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document.

The Kellogg Radiation Laboratory 3.2-Mv electrostatic generator, 90° electrostatic analyzer, and 180° double-focusing magnetic spectrometer have been used to measure the Q-values of the reactions [...], [...] and [...], relative to the [...] threshold energy at 1880.7 ± 0.4 kev (24). These measurements imply an end point energy for the beta transition [...] of [...]. The half-life of O14 has also been measured as t = 71.00 ± 0.13 sec, which implies a partial half-life for the excited state transition of [...] sec. Averaged with the recent half-life measurement of Hendrie and Gerhart (37), the above data lead to an ft-value for the beta transition of ft = 3075 ± 10 sec, corrected for nuclear form factors, electron screening, and competition from K-electron capture (6). With the radiative corrections of Kinoshita and Sirlin (5), the value of the Fermi coupling constant for nuclear beta decay is then calculated from these data as [...], where the error is experimental only. The corresponding value calculated for muon decay is [...], differing by (1.8 ± 0.2)%. While some reservations are still necessary concerning the interpretation of the experimental results, it is felt that the origin of the discrepancy is probably theoretical in nature.

Descriptions are given of the equipment modifications required to achieve the accuracy demanded by the experiment, and an appendix gives a detailed discussion of the theory of nuclear reaction yields from thick targets as observed by particle spectrometers with finite resolution in energy and angle.

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