The Induced Radioactivity of Scandium

Abstract

A study has been made of the radioactivities induced in scandium by bombardment with deuterons, alpha-particles and slow and fast neutrons. ${\mathrm{Sc}}^{46}$ has been produced by deuteron and slow neutron activation. This isotope emits low energy electrons and soft gamma-radiation. The energy distribution of the electrons has been investigated by means of a large hydrogen filled expansion chamber. The upper limit of the spectrum is at 0.89(5) Mev in reasonably good agreement with range measurements made using aluminum absorbers. The half-life of ${\mathrm{Sc}}^{46}$ is 85\ifmmode\pm\else\textpm\fi{}2 days. Alpha-particle bombardment of scandium gives rise to ${\mathrm{V}}^{48}$ which emits positrons and gamma-rays and decays to half-value in 16.2\ifmmode\pm\else\textpm\fi{}0.3 days. Irradiation of scandium with fast neutrons from the ${\mathrm{Be}}^{9}$+${\mathrm{H}}^{2}$ reaction results in the formation of ${\mathrm{K}}^{42}$ only. Bombardment with the neutrons from the Li+${\mathrm{H}}^{2}$ reaction, however, yields ${\mathrm{K}}^{42}$ and both ${\mathrm{Sc}}^{43}$ and ${\mathrm{Sc}}^{44}$. The scandium isotopes emit positrons and decay with half-lives of 4.0\ifmmode\pm\else\textpm\fi{}0.1 hours and 52\ifmmode\pm\else\textpm\fi{}2 hours, respectively. Under these conditions the reaction ${\mathrm{Sc}}^{45}+{n}^{1}\ensuremath{\rightarrow}{\mathrm{Sc}}^{43}+3{n}^{1}$ is twice as probable as ${\mathrm{Sc}}^{45}+{n}^{1}\ensuremath{\rightarrow}{\mathrm{Sc}}^{44}+2{n}^{1}$. No evidence has been obtained of the reaction ${\mathrm{Sc}}^{45}+{n}^{1}\ensuremath{\rightarrow}{\mathrm{Ca}}^{45}+{\mathrm{H}}^{1}$.