IMPROVED THIN FILM MULTILAYER COATINGS FOR THERMAL NEUTRON GUIDES

ADDING MIRROR AND SUPERMIRROR NEUTRON GUIDES TO EXISTING AND PROPOSED THERMAL NEUTRON RESEARCH FACILITIES HAS GREAT ECONOMIC BENEFITS. RECENT DEVELOPMENTS IN MULTILAYER PROCESSING AND COMPUTER SIMULATION OF SPUTTER DEPOSITION SHOW THAT SUPERMIRROR CONSTRUCTION IS APPROACHING THE CAPABILITY NEEDED TO CONSTRUCT LARGE NEUTRON GUIDES. THE KEY REMAINING PROBLEM IS THE DEGREE OF REFLECTIVITY OBTAINED IN A SINGLE GUIDE WALL REFLECTION. THIS PROBLEM ISATTRIBUTED TO THE DEGREE OF "FLATNESS" AT THE ATOMIC LEVEL THAT CAN BE OBTAINED IN A MULTILAYER SUPERMIRROR. THE TECHNICAL OBJECTIVE OF THIS PROJECT IS TO BUILD GUIDE SEGMENTS THAT TEST THE IMPROVEMENTS FACILITATED BY USE OF "SELF-LEVELING" INTERMETALLIC COMPOUNDS AND MECHANICAL STRAIN BUILT INTO THE LAYERS THEMSELVES.