Beta-Ray Spectra of Scandium

Abstract

The positron spectrum of ${\mathrm{Sc}}^{44}$, and the electron spectrum of ${\mathrm{Sc}}^{48}$ have been measured by a spectrometer of high resolution. A Kurie plot of the spectra shows that neither satisfies the Fermi distribution for an "allowed disintegration." The maximum energy of the positrons is 1.45±0.01 Mev, and of the electrons 640±4 kev. Other activities in scandium were too weak to be measured. The spectra have been corrected for width of the slits of the spectrometer, and an experimental check on the accuracy of the correction obtained. The positron decay curve may be resolved into two components, of 4-hr. and 52-hr. half-life, due to a 52-hr. $\gamma$-ray transition to the 4-hr. ${\mathrm{Sc}}^{44}$ positron-emitting level. The conversion coefficient of the $\gamma$-ray is 0.070±0.012, corresponding to a change of angular momentum of 3 units in the transition. The excitation energy of the $\gamma$-ray for deuteron bombardment has been obtained as 4.0±0.2 Mev.