A new radioactivity which we assign to the nucleus ${\mathrm{Ne}}^{18}$ has been investigated. The decay is by the emission of positrons with an upper limit of 3.2±0.2 Mev and a half-life of 1.6 seconds. The spectrum of $\beta$ rays was compared directly in a magnetic spectrograph with the known radiation of ${\mathrm{He}}^6$. The $\beta$-ray energy and decay rate correspond to a $log\mathrm{ft}$ value of 2.9±0.2, placing the activity in the superallowed class.

• Received 8 January 1954

DOI:https://doi.org/10.1103/PhysRev.94.365