If double beta decay occurs without the emission of neutrinos, the total kinetic energy of the two emitted electrons is constant. An experiment has been performed using this constancy of energy and the coincidence nature of the activity in an attempt to observe and identify this process in ${\mathrm{Ca}}^{48}$.

The results show a peak in the total energy spectrum at 4.1±0.3 Mev. Mass spectrographic data gives 4.3±0.1 Mev as the available energy for double beta decay. The author believes this to be evidence for double beta decay without neutrino emission unless the observed counts are due to an unusual phenomenon of unknown origin.

• Received 11 June 1954

DOI:https://doi.org/10.1103/PhysRev.97.1234