Beta-Spectra of Forbidden Transitions

Abstract

The beta-spectra of the forbidden transitions of Y 91 , Sr 89 , Y 90 , Cs 137 , RaE, Au 198 , Re 186 , and P 32 have been measured with thin sources and high resolution. Forbidden type spectra are found for the first five. Au 198 , Re 186 , and P 32 yield spectra with the allowed shape. Evidence is advanced for the reliability of the nuclear shell structure model and for the validity of G.-T. selection rules. End points found are: Y 91 , 1.537±0.007 Mev; Sr 89 , 1.463±0.005 Mev; Y 90 , 2.180±0.007 Mev; Cs 137 , 0.51±0.01 Mev; Au 198 , 0.956±0.005 Mev; Re 186 , 1.063±0.006; and P 32 , 1.689±0.01 Mev.

Internal bremsstrahlung spectra of β− particle emitters using the Monte Carlo method

“…Many first-forbidden distributions and a few second-forbidden distributions can and do have the same shape as allowed distributions. Well-established examples include 32 15 P; 186 75 Re and 198 79 Au (Langer and Price, 1949). In this study, the shape correction factor is ignored.…”

Small-Order Effects in Beta Spectra

“…[11][12][13][14][15][16][17] As the shape factor for this transition is uniquely known, any deviations of the observed spectrum from that predicted by theory should result from instrumental errors.…”

“…Also, as a check on the instruments the unique firstforbidden spectrum of Y 90 was carefully examined. [11][12][13][14][15][16][17] The careful examination of this spectrum also served to indicate the validity with which this type of spectrum could be subtracted from a total beta spectrum.…”

Measurement of the internal bremsstrahlung spectrum of a 89Sr beta emitter in the 1–100keV photon energy regime

“…is the beta spectrum of the beta emitter under consideration and is obtained for the 89 Sr beta emitter from the results of Langer and Prince (1949).…”