ΓnΓfin heavy actinides

Fission probabilities of heavy (mass 245-251) actinides have been determined using previously described techniques. Empirical average $\frac{{\Gamma }_n}{{\Gamma }_f}$ values and fission barrier parameters deduced from statistical model fits to the results are compared with previous results for lighter mass actinides. Odd-$A$ Bk and Es nuclei exhibit a strong dip in $P_f$ above the neutron binding energy, followed by a gradual increase with increasing excitation energy. We are not able to reproduce this trend with statistical model calculations.