Radioactive Isotopes of Scandium from Calcium and Potassium by Alpha-Particle Bombardment

A study has been made of the radioactive isotopes of scandium formed from calcium and potassium by bombardment with alpha-particles. ${\mathrm{Sc}}^{43}$ has been separated chemically from calcium, its half-life being 4.0±0.1 hours. No evidence has been obtained of ${\mathrm{Sc}}^{46}$ or ${\mathrm{Sc}}^{47}$. Two radioactive isotopes of scandium, viz. ${\mathrm{Sc}}^{42}$ and ${\mathrm{Sc}}^{44}$, have been isolated from potassium, these having half-lives of 4.1±0.1 hours and 52±3 hours, respectively. Cloud chamber studies of the positrons emitted by ${\mathrm{Sc}}^{43}$ and ${\mathrm{Sc}}^{42}$ show that the upper limits of the two spectra are 1.3 (8) and 1.6 (3) Mev, respectively.