Waveshifters and Scintillators for Ionizing Radiation Detection

70702B02-II Organic scintillators and waveshifters are fundamental materials used in the detection of ionizing radiation in experimental detectors for high energy physics research, and in other applications such as nuclear medicine and homeland security. Future scientific developments will require improving scintillator and waveshifter response time while maintaining high light efficiency, good uniformity, acceptable radiation resistance, and stable environmental characteristics. This project will develop fast-response, high-efficiency fluorescent dyes for incorporation in organic scintillation and waveshifter materials, in both bulk and fiber-optic form. In Phase I, a set of promising fluorescent dye structures were identified and synthesized. A subset was incorporated into bulk organic plastic materials for preliminary characterization of spectral properties, efficiency, and response time. The dyes with the fastest response time and highest efficiency in the plastic host material were incorporated into organic plastic fibers for further study. Phase II will optimize the compositions and dye concentrations, and assess material stability in the face of radiation damage and environmental conditions. Laboratory tooling and techniques will be established to provide efficient and practical synthesis and purification of the organic dyes in significant quantities. Commercial Applications and Other Benefits as described by awardee: In addition to their application to high energy physics research, new scintillation and waveshifter materials should have application to homeland security (for imaging of shipping containers for the detection of contraband, drugs, and explosives), industrial gauging (where scintillators are often placed in hot environments, to allow longer wavelengths for longer instrument lifetimes), and medical dosimetry (where stable, bright, long-wavelength scintillators are continually being requested).