Relation between Apparent Shapes of Monoenergetic Conversion Lines and of Continuousβ-Spectra in a Magnetic Spectrometer

A method has been worked out for correcting distortions which affect the apparent shape of a continuous β-ray spectrum. Internal conversion lines are studied in the β-spectrometer and found to have a finite width and in the case of 180^∘{} focusing an unsymmetrical shape.On the assumption that these conversion lines are actually monoenergetic, it is possible to calculate the distortion produced by the spectrometer and source, and thus to determine the approximate true shape of the continuous β-ray spectrum from the experimental data.The Kurie plots for a continuous β-ray spectrum corrected in this way are, in general, straight over a greater range than the plots of the uncorrected data. The correction has been applied to the ratio of the number of positrons to the number of negatrons in Cu⁶⁴ and gives results in better agreement with the Fermi theory than if there has been no correction.