An α-spectrum using Si(Au) detectors is obtained with a thin sample of 235U (0.0013 % 234U content). A total of thirteen lines are determined. Direct γ-spectra have been obtained with Ge(Li) and Si(Li) detectors at low energy (x L rays), medium energy (using continuous purification in a resin column) and high energies, enabling the identification of forty-five 231Th γ-rays. A γ-γ two-dimensional coincidence experiment permitted the decay scheme of levels to be established. Some of the suppositions have been verified in α-γ and γ-X L ray coincidence experiments. Eighteen energy levels are established, seventeen being identified terms of the rotational bands 5 2 +(633), the fundamental; 7 2 −(743), the α- favored; 5 2 −(75 3 2 +(631) and 1 2 +(631) also using arguments of previous nuclear reaction work.