Energy filter with fast-counting direct electron detector

带有快速计数直接电子探测器的能量过滤器

• 批准号: 525040890
• 金额: --
• 依托单位: Julius-Maximilians-Universität Würzburg
• 依托单位国家: 德国
• 项目类别: Major Research Instrumentation
• 财政年份: 2023
• 资助国家: 德国
• 起止时间: 2022-12-31 至 无数据
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/525040890?language=en
• 关键词: Energy; filter; fast; counting; direct

Researchers at the Julius-Maximilians-Universität Würzburg investigate the structural determinants by which biological assemblies support a diverse set of functionalities. In 2018 they established an electron cryo microscopy facility for high-resolution structure determination. This facility is used by researchers in and beyond Würzburg. At the heart of the platform is a 300 kV electron microscope with a Schottky type XFEG emitter and a direct electron detector. The detector enables data acquisition in linear mode and in counting mode. The latter gives a detective quantum efficiency, which is close to the theoretical limit. However, due to its low frame rate it limits the throughput to only about 700 movies per day. In contrast, linear mode allows data acquisition of up to 7,000 movies a day but with only about half of the detective quantum efficiency of the counting mode. Sparked by the success with data obtained at the facility, the ambitions of the researchers at the JMU have shifted towards more challenging projects such as smaller, and more dynamic complexes and ligand localization for drug discovery. The success of these projects depends on large data sets with some 5000 movies obtained in counting-mode. With the current equipment, acquisition of such data sets can take a week and more. Even worse, for smaller dynamic complexes (< 150 kDa), the scouting data obtained within 24 hours are often insufficient for judging whether a structure would likely be solved if a larger data set were obtained. Therefore, the current detection system with a slowly counting camera does not fulfill the needs and ambitions of the researchers at the JMU with respect to quality and quantity of image data obtained within a 24-hour slot. To establish whether a different detection system will be more suitable for the needs, researchers compared data obtained for the same sample in Würzburg and elsewhere. These comparisons showed that in addition to counting, energy filtration and zero-loss imaging are other important assets which enable more robust classification of small dynamic complexes and drastically improve the overall resolution. To bring the platform to the current leading standards in image acquisition, we apply for replacing the current detection system with an energy filter and a direct electron detector with fast counting capabilities.

Julius-Maximilians-Universitätwürzburg的研究人员研究了生物组装支持潜水员功能的结构决定者。在2018年，他们建立了一个电子冷冻显微镜设施，以确定高分辨率结构。 Würzburg的研究人员使用了此设施。平台的核心是300 kV的电子显微镜，带有Schottky型XFEG发射极和直接电子检测器。该检测器可以在线性模式和计数模式下启用数据采集。后来给出了侦探量子效率，该效率接近理论极限。但是，由于其较低的框架速率，它每天将吞吐量限制为大约700部电影。相比之下，线性模式允许每天最多7,000部电影获取数据，但仅占计数模式的侦探量子效率的一半。在该设施获得的数据的成功中，JMU的研究人员的野心已转向了更多的挑战项目，例如较小，更具动态的复合物和配体进行药物发现。这些项目的成功取决于大型数据集，在计数模式中获得了大约5000部电影。借助当前的设备，此类数据集的获取可能需要一周或更多。更糟糕的是，对于较小的动态复合物（<150 kDa），如果获得较大的数据集，则在24小时内获得的侦察数据通常不足以判断是否可以解决结构。因此，对于在24小时插槽内获得的图像数据的质量和数量，具有缓慢计数摄像头的当前检测系统无法满足JMU研究人员的需求和野心。为了确定不同的检测系统是否更适合需求，研究人员比较了Würzburg和其他地方的同一样本获得的数据。这些比较表明，除了计数外，能量过滤和零损失成像是其他重要资产，可以使小型动态复合物更加稳健地分类并大大改善总体分辨率。为了使平台达到图像采集的当前领先标准，我们申请使用能量过滤器和具有快速计数功能的直接电子检测器代替当前的检测系统。