Pumping System in EMs
- Practical Electron Microscopy and Database -
- An Online Book -

http://www.globalsino.com/EM/



 

This book (Practical Electron Microscopy and Database) is a reference for TEM and SEM students, operators, engineers, technicians, managers, and researchers.

 

=================================================================================

When a vacuum pump is used to remove gas from another pump, then we can say the latter is ‘backed’ by the former. For instance, turbomolecular and oil-diffusion pumps in high vacuum systems, such as TEMs and SEMs, cannot work directly against atmospheric pressure and need a mechanical pre-vacuum pump in order to function as shown in Figure 4323. In these systems, the primary vacuum pumps, e.g. mechanical pump, can reach a vacuum of > 0.1 Pa, the secondary vacuum pumps such as oil diffusion pumps and turbomolecular pumps can reach a vacuum of <10-4 Pa, and the high and ultra-high vacuum pumps such as ion getter pumps and cold traps, in the gun and specimen areas, can reach a vacuum of < 10-6 Pa.

Pumping System in EMs

Figure 4323. Schematic illustration of pumping system in TEMs.

There are various pumps for TEMs and SEMs, and one often has a choice when purchasing an instrument. However, a clean UHV system is very expensive.

 

 

=================================================================================

The book author (Yougui Liao) welcomes your comments, suggestions, and corrections, please click here for submission. If you let book author know once you have cited this book, the brief information of your publication will appear on the “Times Cited” page.