Conductive, Wavelength-Shifting Optical Coatings for Facilitating the Detection of Neutron/Helium Interaction-Induced Scintillation

The possibility of the existence of a nonzero electric dipole moment (EDM) for neutrons is of great fundamental interest to the nuclear physics community. One approach to investigating the properties of neutrons involves the detection of scintillation following the capture of neutrons by liquid helium. In order to facilitate the detection of the scintillation event, materials are needed that are capable of wavelength-shifting, are transparent to visible light, and are sufficiently smooth to enable the total internal reflection of visible light for guidance to the detector. This project will develop and evaluate conductive and non-conductive, optically clear and smooth coatings on the inside walls of the acrylic cell used to study neutron EDM. In particular, nanoscale self-assembly will be integrated with traditional polymer processing to achieve uniform, transparent, conductive and non-conductive coatings on UV-transmitting acrylic plates. Electrical resistivity will be modeled to predict the desired percolation volume of the conducting material. Using theoretical predictions, polymer composites with single-walled carbon nanotubes will be formulated and processed to achieve the desired optical, electrical, and mechanical properties. Commercial Applications and other Benefits as described by the awardee: This study would provide the following benefits to the DOE: (1) measurement of the magnitude of neutron EDM, and (2) a lowering the current experimental detection limit by one to two orders of magnitude. Achievement of these objectives would have major impact on understanding the physics of both weak and strong interactions.