A CCD Crystallographic X-ray Detector with Lens Optics

我们提出研究荧光粉和CCD传感器在x射线探测器中的透镜耦合，用于大分子晶体学。在这个项目中，我们将开发三种技术：大光圈镜头；高增益荧光粉；背光大画幅ccd。我们已经开发了一个大镜头的原型，现在我们正在描述它的特性。我们开发了一种新的荧光粉（ZnSe:Cu,Ce，CI），它比传统的Gd2O2S:Tb具有更高的增益和更少的余辉。我们建议对这项技术进行研究和改进，特别是寻找一种更快、更亮、不含硒的荧光粉。我们已经开始了一个项目，将61毫米的CCD变薄，用于背光照明，从而提高这些大型CCD的光转换效率。我们建议开发更大的ccd，具有更快的读出速度和更低的噪声，并且是背光的。透镜耦合光学消除了刺、死区和光纤耦合光学的固有缺陷（鸡丝、剪切畸变、光传输不均匀）。相对于光纤耦合，透镜耦合减少了空间畸变和位置不均匀性。点响应应该更好。随着我们期望实现的CCD效率和荧光粉增益的提高，以及这些超大透镜系统可以实现的光传输效率，整体系统增益（存储在CCD/入射X射线中的电子）应该与光纤耦合相当或优于光纤耦合。探测量子效率（DQE）和动态范围也应等同或优于模块化马赛克CCD探测器。在生产中，这种技术应该比镶嵌式ccd便宜得多。

We propose to study lens coupling between the phosphor and the CCD sensor in X-ray detectors for macromolecular crystallography. In this project we will develop three technologies: large aperture lenses; high gain phosphors; and back-illuminated, large-format CCDs. We have developed a prototype big lens, and we are now characterizing it. We have developed a new phosphor (ZnSe:Cu,Ce,CI) with significantly higher gain and less afterglow than conventional Gd2O2S:Tb. We propose to study and improve on this technology, specifically to find a phosphor that is even faster and brighter, and does not contain selenium. We have begun a program to thin a 61mm CCD for back illumination, thus increasing light conversion efficiency in these large CCDs. We propose to develop ever larger CCDs with faster readout and lower noise, that are back-illuminated. Lens-coupling optics eliminates zingers, dead spaces, and the inherent defects of fiberoptic coupling optics (chickenwire, shear distortion, nonuniform optical transmission). Lens coupling reduces spatial distortions and positional nonuniformities relative to fiberoptic coupling. The point response should be better. With improvements in CCD efficiency and phosphor gain that we expect to realize, and the optical transfer efficiency that these very large lens systems can achieve, the overall system gain (electrons stored in the CCD/incident X ray) should be comparable to or superior to fiberoptic coupling. The detective quantum efficiency (DQE) and dynamic range should also be equivalent or superior to modular mosaic CCD detectors. In production, this technology should be substantially cheaper than mosaic CCDs.