A CCD Crystallographic X-ray Detector with Lens Optics

我们建议研究用于大分子结晶学的X射线探测器中的荧光粉和CCD传感器之间的透镜耦合。在这个项目中，我们将开发三种技术：大口径透镜；高增益荧光粉；以及背光源，大尺寸LCD。我们已经开发了一个大透镜的原型，现在我们正在对它进行表征。我们开发了一种新的荧光粉(ZnSe：Cu，Ce，CI)，与传统的Gd2O2S：Tb相比，它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。我们已经开始了一项计划，将61 mm的CCD变薄以用于背光照明，从而提高这些大型CCD的光转换效率。我们建议开发更大的、读出速度更快、噪音更低的背光ccd。透镜耦合光学消除了振荡器、死区和光纤耦合光学的固有缺陷(纤丝、剪切失真、光传输不均匀)。与光纤耦合相比，透镜耦合减少了空间失真和位置不均匀。点位反应应该会更好。随着我们期望实现的CCD效率和荧光粉增益的提高，以及这些超大型透镜系统可以实现的光学传输效率，整个系统的增益(存储在CCD/入射X射线中的电子)应该可以与光纤耦合相媲美或更好。探测量子效率(DQE)和动态范围也应等于或优于模块化马赛克CCD探测器。在生产中，这项技术应该比马赛克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.