Method of Measurement of Cross Sections of Heavy Nuclei Fission Induced by Intermediate Energy Protons

A method of measurement of total fission cross sections and an experimental set-up are described. Experiments are carried out at the 1 GeV synchrocyclotron of PNPI with an updated beam system which allows one to obtain proton beams of various energies from 200 to 1000 MeV with intensity up to 107 protons/s. The proposed measurement method is based on the registration in coincidence of both fission fragments by two parallel plate avalanche counters. The counters together with the target to be investigated are placed directly on the proton beam which provides a large solid angle acceptance. The beam monitoring is performed by scintillation telescopes. The first preliminary results on energy dependences of total fission cross sections of 238U, 235U, 209Bi and natPb are presented.