CCD Camera for Intermediate Voltage Electron Microscopes

中压电子显微镜用 CCD 相机

• 批准号: 7227877
• 负责人: KENNETH H DOWNING
• 金额: $ 33.41万
• 依托单位: UNIVERSITY OF CALIF-LAWRENC BERKELEY LAB
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-05-01 至 2010-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7227877
• 关键词: Automation; Cells; Characteristics; Charge; Condition; Coupled; Data; Data Collection; Data Quality; Deposition; Devices; Dose; Electron Microscope; Electron Microscopy; Electrons; Evaluation; Film; Image; Lateral; Microscope; Noise; Operative Surgical Procedures; Performance; Proteins; Range; Resolution; Scanning; Signal Transduction; Specimen; System; Time; Viral Proteins; Work; charge coupled device camera; design; digital; electron crystallography; improved; particle; protein structure; quantum; reconstruction; voltage

DESCRIPTION (provided by applicant): Charge-coupled device (CCD) cameras have found wide application in electron microscopy. They provide much faster availability of image and diffraction data than photographic film, and this improvement in turnaround time has allowed a tremendous increase in the efficiency of specimen evaluation, microscope operation and automation, and data recording. For some types of work the data collected with a CCD is of higher quality than that recorded on film. However, the CCD performance is seriously compromised when the microscope is operated much above 100 kV, due to the decrease in efficiency of the scintillator. The higher voltages result in a decrease of the signal level and introduction of noise, as well as an increase in lateral scattering of the electrons within the scintillator, which decreases the resolution. Together these effects can produce a detective quantum efficiency (DQE) which is far below that of film, and indeed too low for work such as low-dose imaging of proteins. The use of Intermediate Voltage Electron Microscopes (IVEMs) operating at 300 - 400 kV is increasing as the many advantages of the higher accelerating voltage become more widely recognized, so the CCD performance on these microscopes is becoming more of a limitation. We are building a new CCD camera system designed to overcome the poor performance of CCD cameras on IVEMs by decelerating the electrons before they reach the camera. We mount the CCD so that it can be floated to around 200 kV, so that when the microscope is operated at 300 kV we obtain the advantages of the IVEM but the camera should perform as well as on a 100 kV microscope. Further improvements will be made to the scintillator to produce even better signal and resolution characteristics than currently available. This advance will, in turn, allow us to utilize the newest, very large format CCDs that are fabricated with smaller pixels. These adaptations will produce substantial benefits in work ranging from high-resolution structural studies of proteins and viruses to the three dimensional study of cell ultrastructure.

描述（由申请人提供）：电荷耦合设备（CCD）摄像机已发现在电子显微镜中进行了广泛的应用。与摄影膜相比，它们提供了图像和衍射数据的可用性要快得多，并且在周转时间的这种改进使样品评估，显微镜操作和自动化以及数据记录的效率大大提高。对于某些类型的工作，使用CCD收集的数据比电影中记录的数据高。但是，由于闪烁体的效率降低，当显微镜运行高于100 kV时，CCD性能受到严重损害。较高的电压导致信号水平和引入噪声的降低，以及闪烁体中电子的横向散射增加，从而降低了分辨率。这些效果共同产生侦探量子效率（DQE），该效率远低于膜的效果，实际上对于诸如蛋白质低剂量成像之类的工作太低。在300-400 kV下运行的中间电压电子显微镜（IVEMS）的使用正在增加，因为较高加速电压的许多优势变得更广泛地认识，因此这些显微镜上的CCD性能正变得越来越有限。我们正在建立一个新的CCD摄像头系统，旨在通过在电子到达相机之前减速CCD摄像机在IVEM上的性能不佳。我们安装CCD，以便将其漂浮到200 kV左右，因此当显微镜以300 kV的方式操作时，我们获得了IVEM的优势，但是相机应在100 kV显微镜上执行。将对闪烁体进行进一步的改进，以产生比目前可用的更好的信号和分辨率。反过来，这一进步将使我们能够利用用较小像素制造的最新，非常大的格式CCD。这些适应将在从蛋白质和病毒的高分辨率结构研究到细胞超微结构的三维研究等工作中产生重大益处。