Fission induced innatTa,natW andnatPt targets by 69 MeV monochromatic photons

A study of photofission on natTa, natW and natPt nuclei induced by monochromatic photons of 69 MeV has been performed. The fission yields have been measured by using makrofoil sheets as fission-track detectors, in thick-target 2 pi geometry. The absolute photofission cross sections for the tantalum, tungsten and platinum targets are found, respectively, to be 4.8+or-1.0 mu b, 5.2+or-1.2 mu b and 10+or-2 mu b, and the corresponding deduced fissilities are (3.2+or-0.7)*10-4, (3.4+or-0.8)*10-4 and (6.4+or-1.3)*104-4.