Direct Synthesis of Li₃N Thin Layer on Lithium Target Surface for BNCT in N₂ Gaseous Conditions

Abstract

To prevent vaporization damage of BNCT (Boron Neutron Capture Therapy) lithium target during operation, direct synthesis of Li₃N thin layer on lithium target surface was demonstrated in 0.1 MPa N₂ gas at temperature below 548 K and the following conclusions were derived; (1) Synthesis of Li₃N thin layer on lithium surface was confirmed after nitridation at 276–548 K with surface contamination by oxygen and carbon. (2) Rapid nitridation over 1–5 mass%/min was observed above Li melting temperature, whereas slow reaction under 0.02–0.5 mass%/min below melting temperature. (3) During nitridation, removal of oxygen contamination on Li₃N thin layer is taken place by nitrogen below Li melting temperature.