Luzzi D E
Department of Materials Science, University of Pennsylvania, Philadelphia 19104-6272.
J Electron Microsc Tech. 1990 Aug;15(4):406-13. doi: 10.1002/jemt.1060150411.
Owing to the particular environment of the JEM4000EX HREM at the University of Pennsylvania, it became necessary to control the magnetic environment around the microscope. The unstable magnetic environment included two components, a slowly wandering vertical DC magnetic field and an AC magnetic field. The effects of these fields on the microscope performance were to introduce an uncertainty in the objective lens defocus value over a series of images and to reduce the attainable resolution of the microscope, respectively. A solution is presented in which these fields are stably reduced well within the limits of sensitivity of the JEOL, Ltd. JEM4000EX for high-resolution imaging. This solution is based on a feedback loop using a pseudo-Helmholtz coil to generate a well-defined vertical magnetic field.
由于宾夕法尼亚大学JEM4000EX高分辨电子显微镜所处的特殊环境，有必要对显微镜周围的磁场环境进行控制。不稳定的磁场环境包括两个部分，一个是缓慢变化的垂直直流磁场，另一个是交流磁场。这些磁场对显微镜性能的影响分别是在一系列图像上引入物镜散焦值的不确定性以及降低显微镜可达到的分辨率。本文提出了一种解决方案，即在JEOL有限公司JEM4000EX高分辨率成像的灵敏度范围内，将这些磁场稳定地降低到很低水平。该解决方案基于一个反馈回路，利用一个伪亥姆霍兹线圈来产生一个明确的垂直磁场。
