Experimental and Evaluated Subthreshold Fission

Full text of publication follows: A critical review is given of subthreshold fission measurements with emphasis on the resonance region. Uncertainties concerning the experiments and their interpretation are discussed. In parallel, the content of the major evaluated data files (Jeff.1, Endf/B-VII and JENDL3.3), in terms of subthreshold fission cross sections, is also carefully examined. In the unresolved resonance region, the use of resulting average resonance parameters for evaluations is addressed. Recommendations are finally drawn on resolved and unresolved subthreshold fission parameters and cross sections. Some remarks on fission fragment mass distributions in the subthreshold region are added. (authors)