Development of a Very Large CCD Area Detector

超大型CCD面探测器的研制

• 批准号: 0116615
• 负责人: Edwin Westbrook
• 金额: $ 60万
• 依托单位: Molecular Biology Consortium
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-05-01 至 2005-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0116615&HistoricalAwards=false
• 关键词: Development; Very; Large; CCD; Area

A grant has been awarded to Dr. Edwin M. Westbrook at the Molecular Biology Consortium (MBC) in Chicago, to develop a state-of-the-art X-ray detector for structural molecular biology research. When the prototype has been completed, it will set the standard for future detectors in this class. The application for this detector is protein crystallography, to be conducted at a synchrotron beamline of the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory (LBL). Protein crystallography is progressively taking advantage of the nation's synchrotron X-ray sources, because they provide million-fold brighter X-ray beams than can be had at home laboratories, and the beam is also much narrower and of more uniform energy. Once the molecular biology community learned to use these magnificent beamlines, enormous advances have been made in structural knowledge of biological systems at the molecular level. Recent determination of the molecular structures of the ribosome subunits and of the RNA polymerase II are merely examples of results that could not have been achieved without synchrotron X rays. The detector that will be developed in this project will further amplify the capabilities of the synchrotron beamline on which it will be installed.While the science of molecular biology is the driving reason for developing this detector, the project itself will be predominantly one of electronic engineering. The detector will feature advanced new Charge-Coupled Devices (CCDs) that have recently been developed that have lower noise and faster performance than previous CCDs. Application-Specific Integrated Circuits (ASICs) and Field-Programmable Gate Arrays (FPGAs) will be integrated into the control system of the detector, and its readout system will be the new S-LINK parallel fiberoptic interface. The MBC electronics group is well known for its extremely low-noise analog electronics, but this detector will also feature radically new digital signal processing to reduce the uncertainty of reading the electronic charge of each CCD pixel, permitting up to 18-bit readout registration.The new detector will have a square active area 32 cm on each side, that can be repetitively observed every 0.67 seconds. It will have a dynamic range- the ratio of strongest/weakest signals it can simultaneously detect- exceeding 250,000:1. Its spatial resolution will permit neighboring Bragg spots to be measured even when they are only 0.6 mm apart, so this detector will be able to resolve over 500 spots across its 32 cm width. All of these characteristic parameters exceed those of existing crystallographic detectors, and taken together as a whole this detector will be dramatically better than any now available.

芝加哥分子生物学联合会（MBC）的Edwin M. Westbrook博士获得了一笔赠款，用于开发用于结构分子生物学研究的最先进的x射线探测器。当原型完成后，它将为这类未来的探测器设定标准。该探测器的应用是蛋白质晶体学，将在劳伦斯伯克利国家实验室（LBL）的先进光源（ALS）的同步加速器光束线上进行。蛋白质晶体学正在逐步利用国家的同步加速器x射线源，因为它们提供的x射线比国内实验室的x射线亮百万倍，而且光束也窄得多，能量更均匀。一旦分子生物界学会了使用这些壮丽的光束线，在分子水平上生物系统的结构知识就取得了巨大的进步。最近对核糖体亚基和RNA聚合酶II的分子结构的测定仅仅是没有同步加速器X射线就无法获得结果的例子。将在这个项目中开发的探测器将进一步扩大将安装在其上的同步加速器光束线的能力。虽然分子生物学是开发这种探测器的驱动因素，但该项目本身将主要是电子工程之一。该探测器将采用最新开发的先进新型电荷耦合器件（ccd），该器件比以前的ccd具有更低的噪声和更快的性能。专用集成电路（asic）和现场可编程门阵列（fpga）将集成到探测器的控制系统中，其读出系统将是新的S-LINK并行光纤接口。MBC电子集团以其极低噪声的模拟电子产品而闻名，但该探测器还将采用全新的数字信号处理，以减少读取每个CCD像素的电子电荷的不确定性，允许高达18位的读出注册。新的探测器将有一个正方形的32厘米的活动区域，每0.67秒可以重复观察一次。它的动态范围——它能同时检测到的最强/最弱信号的比值——将超过25万：1。它的空间分辨率将允许相邻的布拉格点被测量，即使它们之间只有0.6毫米的距离，所以这个探测器将能够在其32厘米的宽度上分辨超过500个点。所有这些特征参数都超过了现有的晶体探测器，并且作为一个整体，这个探测器将比现有的任何探测器都要好得多。