 To facilitate the work, a small plant was established at the Anchor Ranch for casting explosive shapes.Throughout 1943, implosion was considered a backup project in case the gun-type proved impractical for some reason.Theoretical physicists like Bethe, Oppenheimer and Teller were intrigued by the idea of a design of an atomic bomb that made more efficient use of fissile material, and permitted the use of material of lower purity.