Fission fragment damage in tungsten

The study of fission fragment damage in tungsten by field-ion microscopy described in an earlier paper (Bowkett et al. 1965) has been continued. Prepared specimens have been bombarded with a collimated beam of fission fragments at a measured inclination to the specimen axis, giving results which show that in small specimens a column of material can be pushed out along the fission fragment path. These findings lend support to the explanation advanced for the light contrast tracks observed by electron microscopy of thin foils that have been irradiated with fission fragments (e.g. Bowden and Chadderton 1962).