Measurement of photo-fission yields and photo-neutron cross-sections in 209 Bi with 50 and 65 MeV bremsstrahlung

The photo-fission yields and photo-neutron cross-sections of ( γ , 3 n ) and ( γ , 4 n ) on 209 Bi induced by 50 and 65MeV bremsstrahlung have been measured by using a recoil catcher and an off-line γ -ray spectrometric technique. The mass-yield distribution of fission products in 209 Bi induced by bremsstrahlung photons from the present work and literature data in the energy range 28-85MeV is symmetric around 103 mass units. However, the full width at half maximum of the yields distribution increases from 19 mass units at 28-40MeV to 23 mass units at 85MeV. The ( γ , 3 n ) reaction cross-section in the 50MeV and the ( γ , 4 n ) reaction cross-section in the 50 and 65MeV bremsstrahlung-induced reaction of 209 Bi were determined for the first time.