A study of the growth of etch pits in CR-39 using a silicon rubber cast technique

CR-39, irradiated normally with alpha particles and fission fragments from a thin californium-252 source, was etched for a range of times up to 18 hours in 6.25 N sodium hydroxide at 700C. Liquid silicon rubber compound, placed on the surface of the CR-39 under vacuum, was allowed to set and removed to give an accurate cast of the etch pits. Electron micrographs of the pit casts show in detail how the pits develop under caustic etch and allow estimates to be made of the variation with time of the bulk and track etch rates. (author)