Abstract
New scavenging method is designed to obtain calcium fluoride crystals which optical properties are excellent, eg. internal trans-mittance and laser durability. Reaction processes between scav-engers and raw material are examined by degas analyzing during heating. The results suggest the simple method that raw material with scavenger is heated in vacuum atmosphere is not enough to make scavenging process progress completely. Then, two steps are applied. The first step, scavenging reaction progess in inert gas atmosphere during the heating process. And the second step, degas of remained scavenger and reaction products progress in vacuum atmosphere. Using this method, optical properties of cal-cium fluoride crystals improved very much.
