SBIR Phase II: Micromachined Scintillating Pixel X-Ray Imaging Plate

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This Small Business Innovative Research Phase II project focuses on x-ray and particle imaging of biological specimens using radionuclides, radiotracers or x-ray beams. An imaging detector requires:unity detection efficiency, photon counting; high spatial resolution film; improved contrast due to insensitivity to scattered x-rays or particles; linear response; dynamic range; low noise; and, differential attenuation imaging using x-ray energies. The research will address these issues with a novel form of high spatial precision imaging scintillator pixel plate, fabricated by micromachining of very high aspect ratio (length/diameter) holes in Si. The microchannels will be formed into dielectric waveguides (optical fibers) by forming a wall cladding film, for example, by oxidizing the walls to form SiO2. Because the Si/SiO2 microchannels can be taken to high temperatures, crystalline scintillators such as BG0, Nal or Csl can be vacuum melted to fill the holes, along with the scintillating glasses, plastic scintillators, and nanocrystalline scintillators. The resulting scintillating pixel plate will have features fully adjustable in size by photolithographic techniques, with holes from one micron to one millimeter in diameter, and, plate thickness up to approximately two millimeters. 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 lead 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.