Viscosity, fission time scale and deformation of 156Dy

In the fusion-fission reaction 40Ar + 116Cd → 156Dy∗ → fission, at Eb = 216 MeV and 238 MeV, γ-rays were measured in coincidence with fission fragments. The interpretation of the γ-ray spectra is done with the help of a modified version of the statistical-model code CASCADE. The spectra can be reproduced with nuclear viscosities in the range 0.01 < γ < 4. The extracted fission time scale is of the order of 10−19 s. The CASCADE analysis seems to favor a prolate deformation with β ≈ 0.45.