Hitachi Atomic Resolution TEM with In-situ Gas Injection-Heating Capability

How gas environmental TEM (E-TEM) is realized?
Transmission electron microscopes work at high vacuum (10-7torror higher) to prevent oxidation and contamination of the electron sources and to avoidelectron scattering in air. In order to introduce gas in the sample area, there are two typical ways to accommodate the gas pressure.
Method 1, E-cell: Seal the sample in a cell confined by electron transparent windows. The windows for this type of environmental cell (E-cell) are typically made from nonporous amorphous carbon or amorphous silica. The advantage of this method is relatively simple and low cost, but the drawbacks are obvious. The total thickness of windows and sample makes the atomic resolution imaging very difficult. Sample tilting and heating in the microscope are also big concerns.
Method 2, differential pumping E-TEM: This approach is to add a differential pumping system to the microscope to maintain the required high vacuum inthe rest of the microscope column when gas pressure is introduced into the sample chamber. The sample now is directly exposed to the electron beam therefore high resolution imaging, sample tilting and heating are not a problem although large-angle electron diffraction becomes impossible. The specially modified E-TEM is not available as a regular products, special order causes much more expensive price, longerdelivery and installation time, and high maintenance cost compared with the regular TEM products.