Optimization of low-cost CZT for nuclear imaging devices

描述(由申请人提供)： 放射性核素成像是观察大脑和其他器官内生理过程的重要工具。传统的放射性核素成像系统依赖于基于闪烁体的探测器。宽禁带半导体，如碲化镉锌(CZT)，与基于闪烁体的系统相比具有显著的优势，包括更高的能量和空间分辨率、紧凑性和更好的信噪比。到目前为止，大多数探测器级CZT是由美国的高压布里奇曼(HPB)技术生长的。由于产量低，探测器级材料价格昂贵。Imarad(以色列)正在使用低压水平布里奇曼技术以较低的价格制造大尺寸CZT，但极低的电阻率CZT会增加探测器的噪声。第二阶段项目的目标是优化一种替代晶体生长方法，即改进的垂直布里奇曼(MVB)技术，以在美国生长更大尺寸和更低成本的CZT。因此，第二阶段研究的具体目标是： 1.利用MVB技术继续优化直径为3“的CZT晶体的生长。 2.建造一个直径4英寸的MVB电炉，并用它来生产用于成像应用的大尺寸CZT晶片 3.系统地表征所有MVB生长的3“和4”直径钢锭，以评估产量并为目标1和2提供反馈。 4.开发制造CZT探测器的能力，包括具有复杂电极几何形状的探测器，如像素阵列。 这项研究将为床边提供一种重要的核医学成像工具，并将展示MVB CZT新技术在核医学中的全部潜力。

DESCRIPTION (provided by applicant): Radionuclide imaging is an important tool for observing physiological processes within the brain and other organs. Traditional radionuclide imaging systems rely on scintillator-based detectors. Wide bandgap semiconductors such as cadmium zinc telluride (CZT) offer significant advantages over scintillator-based systems including superior energy and spatial resolution, compactness, and better signal to noise ratio. To date, most detector grade CZT is grown by the High Pressure Bridgman (HPB) technique in U.S.A. Detector grade material is costly because of low yields. Imarad (Israel) is making large-size CZT using low presure horizontal Bridgman technique with lower price, but the CZT with very low resistivity will increase the detector noice. The goal of the Phase II project is to optimize an alternative crystal growth method, the modified vertical Bridgman (MVB) technique, for growing larger size and lower cost CZT for nuclear imaging in united states. Thus, the specific aims of the Phase II research are: 1. Continue to optimize the growth of 3" diameter CZT ingots using MVB technique. 2. Construct a 4" diameter MVB furnace and use it to produce lager-size CZT wafers for imaging applications 3. Systematically characterize all MVB grown 3" and 4" diameter ingots to evaluate yields and provide feedback for Aim 1 and 2. 4. Develop the capability to prodcess CZT detectors including those with complex electrode geometries such as pixel arrays. This research will produce an important nuclear medicine imaging tool for bedside and will also monstrate the full potential of the new MVB CZT technique in nuclear medicine.