Changing the colouring of hard and gem stones - using high energy level rapid neutrons and gamma particles

摘要

Gem stones are treated in a reactor by neutrons and the gamma-particles accompanying them. Rapid neutrons having an energy of >=0.5 MeV are applied in integral doses of 5 x 1015 to 1 x 1018 neutrons/cm2, together with gamma-particles in integral doses of 5 x 106- 1 x 109 R at 300 degrees C. In the process, thermal neutrons with an energy 0.5 MeV are filtered out by foils of Cd, and colours are obtd. which are highly valued in the jewellery trade. The colours are resistant to UV light, and the induced radioactivity approaches the base level very quickly.