Pair decay of the 15.1 MeV level of ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$

We have observed the $e^{+}{e}^{-}$ pair line from the decay of the 15.1 MeV level of ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$. Pairs were detected using an intermediate image pair spectrometer. The use of this line as a calibration point for beta spectrometers is discussed.

RADIOACTIVITY ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$; observed $e^{+}{e}^{-}$ pair line from 15.1 MeV level. Intermediate image pair spectrometer.