The positron spectrum of ${\mathrm{F}}^{18}$ was investigated with a magnetic lens spectrometer and found to be of the allowed type with an upper limit at 649±9 kev. The gamma-radiation from ${\mathrm{Mo}}^{93}$ was found to consist of three lines at 262±2 kev, 692±11 kev, and 1.51±0.035 Mev. The $K$ to $L$ conversion ratio for the low energy line indicates $2^5$ pole electric radiation. The positron spectrum of ${\mathrm{Cl}}^{34}$ consists of three components with upper limits at 4.45 Mev, 2.6 Mev, and 1.3 Mev. Gamma-ray lines were found at 3.3 Mev and 2.1 Mev and at 0.145±0.003 Mev. The latter line gives rise to internal conversion electrons.

• Received 16 April 1951

DOI:https://doi.org/10.1103/PhysRev.83.698