The `External' Photoelectron Spectrum and the Intensities of the  -Rays of Thorium (B+C+C'')

The spectra of the photoelectrons ejected from various targets by the γ-rays of Th(B+C+C'') have been measured and the emission probabilities of the γ-rays of energy 0.238, 0.277, 0.299, 0.510, 0.582, 0.726, and 0.859 MeV. have been estimated. Using the known intensities of the internal conversion lines, coefficients of internal conversion have been found. The four low-energy rays seem to be magnetic dipole in character with some electric quadripole admixture, but the strong 0.582 MeV. ray of 208 Pb is predominantly electric quadripole. The possible spins of the nuclear levels are discussed.