SpontaneousC14emission fromRa223

The spontaneous emission of ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$ from ${}_{}{}^{223}{}_{}{}^{}\mathrm{Ra}$, recently discovered by Rose and Jones, has been confirmed, and the mass of the emitted particles unambiguously identified. The present measurement was performed with a ${}_{}{}^{227}{}_{}{}^{}\mathrm{Th}$ source containing 9.2 mCi of ${}_{}{}^{223}{}_{}{}^{}\mathrm{Ra}$. An Enge split-pole magnetic spectrograph was used to suppress the intense alpha radiation and to identify the ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$ particles. The spectrograph was calibrated with tandem-accelerated beams of ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$, and ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$. In six days of decay counting, twenty-four ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$ events were observed yielding a branching ratio of (4.7±1.3)×${10}^{\mathrm{-}10}$ for the emission of ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$ from ${}_{}{}^{223}{}_{}{}^{}\mathrm{Ra}$ relative to that of alpha particles. The value is in fair agreement with the result of Rose and Jones, (8.5±2.5)×${10}^{\mathrm{-}10}$, and with more recent measurements from other laboratories.