The Radiations Emitted from Artificially Produced Radioactive Substances IV. Further Studies on the Gamma-Rays from Several Elements

Further studies on the gamma-radiation from V⁴⁸, N¹³, Cu⁶⁴, Mg²⁷, and Na²⁴ have been carried out using a large hydrogen-filled cloud chamber and with several improvements in technique. The most striking feature of the spectra, is the presence of a large amount of 1 Mev radiation from V⁴⁸. Comparison with the ordinary annihilation radiation indicates that there are four 1 Mev quanta emitted per positron. The possible origin of this radiation is discussed. A difference in the gamma-radiation emitted from N¹³ and Cu⁶⁴ is noted, the latter having a more pronounced high energy tail. A small number of tracks from Mg²⁷ have been measured and indicate a monochromatic line at 0.88±{}0.05 Mev. The radiation from Na²⁴ has been re-examined. The results indicate that the quantum energy of the high energy line is 3.00±{}0.05 Mev. The two other lines with energies of 2 Mev and 1 Mev are confirmed.