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

这一小型企业创新研究第二阶段项目的重点是使用放射性核素、放射性示踪剂或X射线束对生物标本进行X射线和粒子成像。成像探测器要求：单位探测效率，光子计数；高空间分辨率胶片；由于对散射的X射线或粒子不敏感而改善的对比度；线性响应；动态范围；低噪声；以及使用X射线能量的差分衰减成像。这项研究将用一种新型的高空间精度成像闪烁体像素板来解决这些问题，这种像素板是通过微加工硅中非常高的长径比(长径比)孔而制成的。微通道将通过形成壁包覆膜来形成介质波导(光纤)，例如通过氧化壁来形成SiO_2。由于硅/二氧化硅微通道可以被带到高温下，晶体闪烁体，如BG0，NaL或CSL，可以与闪烁玻璃、塑料闪烁体和纳米晶体闪烁体一起真空熔化来填充孔洞。由此产生的闪烁像素板将具有可通过光刻技术完全调整大小的特征，具有直径从1微米到1毫米的孔，并且板厚度最大可达约2毫米。闪烁体阵列与光学像素探测器的精度和空间分辨率很好地匹配，包括CCD、图像增强器和胶片。该计划可能导致新的大面积、高精度X射线成像仪，使医疗和牙科X射线中的胶片更换或增强胶片成为可能。它还可能以低成本制造超高精度的光纤板，以及紧凑的全口径光学和X射线准直器。

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.