Key points of environmental design and construction of high-end electron microscope laboratory

As a high-precision electronic optical instrument with ultra-high resolution, electron microscope(EM) has been widely used in the scientific research, including industry, medical care, food safety, life health, and many other fields, and becoming an important tool for conducting testing, characterization as well as scientific research on the modern material form and microstructure. In recent years, with the rapid development and application of the spherical/chromatic aberration corrector and the state-of-the-art in-situ EM technology, it is no longer so difficult to obtain atomic-scale(static or dynamic) micro-structure images. Moreover, the development and popularity of Cryo-electron microscopy has brought innovation to the study of biomacromolecules, soft matter, etc. Associated with the great performance improvement of EM, the requirements for the operating environment become even higher. For instance, it usually takes several days to perform data collection in a single case regarding the structure analysis of macromolecular complexes using cryo-TEM, which raises stricter requirements for the EM stability. Therefore, environmental index and its stability are crucial to the device operation. Now, it is a priority for the EM workers/users to build a stable condition for EM, particularly the high-end EM, in order to continuously obtain high-quality images, improve the utilization rate of the EM, and decrease equipment failure rate as well as the cost. Generally, the stable environment is the foundation and prerequisite for the high-performance achievement of EM. Environmental magnetic field, vibration, temperature and its fluctuation, humidity, independent grounding, supply systems(e.g., electron power and cooling water) and auxiliary machine room and others factors will affect the stable operation and performance of EM significantly. These factors are also key performance evaluations for environmental improvements. In this paper, based on the authors’ relevant experience, some key points for the environmental improvement of high-end EM are briefly discussed, providing references/advice for the EM users.