Measurements of subthreshold photofission angular distributions of 238U and fission channel analysis

Measurements of photofission fragment angular distributions of 238U between 5.1 and 6.0 MeV are presented. As #betta#-source the intense bremsstrahlung beam from the Catania University Microtron is used. The results are analyzed within the framework of the double-humped barrier model with a potential constructed with three smoothly joined parabolae and a damping term in the second well. The values of the fission barrier parameters for the involved 2+0, 1-0 and 1-1 channels are extracted and a comparison with the theoretical predictions and experimental results in the literature is made. Delayed-fission contributions for the involved channels are taken into account in the 1-1 channel parameter determination. (author)