This Small Business Innovative Research Phase I project focuses oil x-ray and particle imaging of biological specimens using radionuclides, radiotracers or x-ray beams. An imaging detector requires: detection efficiency close to unity; photon counting; high spatial resolution, comparable to film; improved contrast due to insensitivity to scattered x-rays or particles; liticar intensity response; large dynamic range; low noise; and differential attenuation imaging using x-ray energies. We propose to address these issues with a novel form of' high spatial precision imaging scintillator pixel plate, fabricated by micromachining of very high aspect ratio holes (length/diameter) in silicon. The Si holes will be formed into dielectric waveguides (optical fibers) by forming a cladding film, for example by oxidizing the walls to form SiO2. The holes will be filled with standard and novel scintillation materials, including index-matched collodal dispersions of nanocrystalline photolithographic techniques, with holes from 1 um-1 mm in diamiter, and plate thickness up to about 1 mm. The scintillator array is well-matched to the precision and spatial resolution of optical pixel detectors including CCD image intensifiers and film. This program may led to novel large area, high precision x-ray imagers, enabling replacement of film or enhancing film in medical and dental x-rays. It may also lead to ultra-high precision fiber-optic plates at low cost, and compact full aperture optical and x-ray collimators.
