Radiochemical Studies on the Photofission of Thorium

The relative yields of thirteen products resulting from the photofission of ${\mathrm{Th}}^{232}$ have been determined radiochemically. Photofission was induced by a 69-Mev synchrotron bremsstrahlung beam. The photofission yield curve was shown by these data to have two peaks, occurring approximately at nucleon numbers 91 and 138 with values of 6.9 percent. The peak-to-valley ratio was 10 and the half-width of the peaks was 12. Symmetry of the curve about nucleon number of 114.5 indicated the average emission of approximately three neutrons. The results were compared with other photofission data and the yield curves of other fission processes.