Extended Lifetime Neutron Chopper System

75073-Conventional mechanical neutron choppers, used in neutron facilities for materials research, rely on oil- or grease-based lubrication to operate continuously at speeds up to 7200 rpm. However, further reductions in the friction are required, especially during maintenance periods when the chopper remains activated. This project will develop a low friction carbon coating ¿ specifically, a nearly frictionless carbon film (a unique form of diamond-like-carbon) ¿ as a replacement for the grease-based lubrication system in conventional neutron choppers. Phase I will: (1) optimize the properties of the near-frictionless carbon coatings for chopper bearings, (2) test the friction and wear properties of all bearing components with and without the coating, and (3) design a prototype. Commercial Applications and Other Benefits as described by the awardee: The new neutron chopper should be more cost effective. In addition, the bearing technology should have spin-off application in semiconductor dry pumps and in rotating anode X-ray tubes, which are components of such diagnostic devices as magnetic resonance imaging.