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Design and Implementation of a Site for a One-Ångstrom TEM

Published online by Cambridge University Press:  02 July 2020

John H. Turner ,
M.A. O'Keefe  and
M.A. O'Keefe
John H. Turner
Affiliation:
National Center for Electron Microscopy, University of California, LBNL B72, Berkeley, CA94720
M.A. O'Keefe
Affiliation:
National Center for Electron Microscopy, University of California, LBNL B72, Berkeley, CA94720
M.A. O'Keefe
Affiliation:
Philips Electronic Instruments, Fremont, CA94538
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Extract

The National Center for Electron Microscopy has recently acquired a field-emission TEM to form thebasis of a project to achieve a resolution of one Ångstrom. To reach this resolution, both instrumental and environmental factors need to be considered. We have designed and constructed a new building to provide a suitable environment for this instrument, with emphasis on providing isolation from external influences detrimental to the achievement of ultra-high resolution. Such influences include mechanical vibration, temperature fluctuations, acoustic noise, and stray electromagnetic fields.

The microscope chosen for the one-Ångstrom project is a Philips CM300 Ultra-Twin equipped with a field-emission gun. Pre-installation specifications provided by Philips for this 1.7Å-resolution TEM specify maximum-allowable values for vibration levels in three mutually-perpendicular directions. In the most critical direction (console left to right), vibration is required to remain below 0.8)μm/sec in the frequency range from 1Hz to 5Hz, although allowed to rise to 6μm/sec above 10Hz (Region I in fig. 1). Even when resolution is not a critical requirement, vibration must be minimized at 2.5Hz (Region II in fig.1).

Type
The Limits of Image Resolution: Seeing is Believing
Information
Microscopy and Microanalysis , Volume 3 , Issue S2: Proceedings: Microscopy & Microanalysis '97, Microscopy Society of America 55th Annual Meeting, Microbeam Analysis Society 31st Annual Meeting, Histochemical Society 48th Annual Meeting, Cleveland, Ohio, August 10-14, 1997 , August 1997 , pp. 1177 - 1178
Copyright
Copyright © Microscopy Society of America 1997

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References

1. O’Keefe, M.A., Ultramicroscopy 47 (1992) 282–297.CrossRefGoogle Scholar

2. A. O’Keefe, Michael (1997) in 55th Ann Proc. MSA, these proceedings.Google Scholar

3. Philips Electron Optics Pre-Installation Instruction Manual.Google Scholar

4. Work supported by the Office of Energy Research, Office of Basic Energy Sciences, Material Sciences Division of the U.S. Department of Energy, under contract No. DE-AC03-76SF00098.Google Scholar