With the modern ultra high vacuum technology, it is easy to achieve 10−1 Torr vacuum. This is when a vacuum chamber has been designed and built specifically for this purpose. Electron microscope column is not a simple vacuum chamber. It is a precision equipment that allows electron microscopy of various specimens. The column is designed primarily for high resolution microscopy and it is not necessarily suitable for achieving ultra high vacuum condition. This is clear from a long TEM history. No dependable ultra high vacuum microscope has ever been built until very recently. Many attempts have been made so far to convert conventional microscopes into UHV-microscope, particularly specimen chamber area.