Internal Compton effect in 113In

Previous measurements of the eγ double decay of 113In at 35degree have been extended to relative angles of emission of 15, 30, 45, 60, 90, 120, and 150degree. The energy distributions of photons have been determined at each angle in the range from 30 to 210 keV and from 35 to 197 keV for Kγ and (L + M + N) γ decays, respectively. The data are in agreement with the theory of the internal Compton effect of Spruch and Goertzel and the theory of radiation losses in internal conversion of Baumann and Robl. The maximum of the transition probability has been found at (39.8 plus-or-minus 2.2) degree, while that predicted by the theories is at 34.6degree. The calculations have also been performed using the theory of ''nuclear'' eγ double decay of Grechukhin. It has been shown that the contributions of this mechanism to the observed results are negligible. The integral coefficients obtained are B/subK/γ = (1.11 plus-or-minus 0.04) times 10/sup -3/ for photons in the energy range from 35 to 105 keV and B/sub L+M+N)++gamma = (1.01 plus-or-minus 0.08) times 10/sup -3/ for photons in the energy range from 42 to 105 keV