Experiments With Dipole and Monopole Lenses for an SEM

芝加哥大学的Albert Crewe获得了一项仪器开发补助金，用于完成、测试和演示一种新的原创扫描电子显微镜（SEM），该显微镜使用一种新型透镜系统，其预期性能特征远远超过现有仪器。它是一种专用的低电压，高分辨率仪器，包含一个永久磁铁透镜，放置在标本下方。这种镜头以前从未使用过，但它们有望大幅提高分辨率。这些镜头的特殊价值是，他们允许使用非常小的焦距与相应的低像差。这使得它特别有价值的使用与低加速电压，虽然镜头并不局限于这个领域。第二个优点是，简化和更通用的柱设计是允许的，由于后标本镜头的位置。第三个优点是，整个仪器的预期成本，如果商业化，应该是目前高分辨率扫描电子显微镜的一半左右。最后，透镜的形状使得它很容易为样品提供一个大的倾斜角度。该项目包括培训一些学生，他们将获得宝贵的仪器设计和开发经验。

An Instrument development grant has been awarded to Albert Crewe of the University of Chicago to complete, test, and demonstrate a new and originalscanning electron microscope (SEM), using a novel lens system, whose expectedperformance characteristics far exceed those of existing instruments. It is a dedicated low voltage, high resolution instrument that incorporates a permanent magnet lens, placed below the specimen. Such lenses have not been used previously but they show promise of permitting a considerable increase in resolution. The special value of these lenses are that they allow the use of very small focal lengths with correspondingly low aberrations. This makes it especially valuable for use with low accelerating voltages, although thelenses are not limited to this area. A second advantage is that simplified and more versatile column designs are allowed due to the post-specimen lens location. A third advantage is that the anticipated cost of the entire instrument, if made commercially, should be about half that of current high resolution scanning electron microscopes. Finally, the shape of the lens makes it easy to provide a large tilt angle for the specimen. The project involves the training of a number of students who will gain invaluable instrument design and development experience.