Angular anisotropy of intermediate energy nucleon-induced fission of actinide and subactinide nuclei

New results of measurements of the angular distributions of proton-induced fission fragments of 182, 183, 184, 186W in the proton energy region 50--180 MeV are presented. The results are discussed together with earlier data, obtained for subactinide nuclei 204,206,207,208Pb and 209Bi and actinide nuclei 232Th and 233, 235, 238U, for both proton- and neutron-induced fission. Similarity is noted of values and energy dependences of angular anisotropy of fission induced by protons and neutrons (taking into account a trivial effect of Coulomb factor) as well as influence on the anisotropy value of the emission character of fission of actinide nuclei and its connection with parameter of fissionability Z2/A

Nucleon-induced fission cross sections of tantalum and separated tungsten isotopes and "compound nucleus" effect in intermediate energy region

Neutron- and proton-induced fission cross sections of separated isotopes of tungsten (182W, 183W, 184W, and 186W) and 181Ta relative to 209Bi have been measured in the incident nucleon energy region 50--200 MeV using fission chambers based on thin-film breakdown counters (TFBC) using quasi-monoenergetic neutrons from the 7Li(p,n) reaction and at the proton beams of The Svedberg Laboratory (TSL), Uppsala University (Uppsala, Sweden). The results are compared with predictions by the CEM03.01 event generator, as well as with the recent data for nuclei in the lead-bismuth region. The effect of ``compound nucleus'' in the intermediate energy region is discussed, displaying in exponential dependence of nucleon-induced fission cross sections on the parameter Z2/A of the composite system (projectile+target nucleus), and in other characteristics of the fission process for which parameter Z2/A plays a role similar to the one of the usual liquid-drop parameter Z2/A of compound nuclei