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Vacuum and Gas Kinetics
Published in Eiichi Kondoh, Micro- and Nanofabrication for Beginners, 2021
A sputter-ion pump traps impurity (residual) gases through chemical reactions between the ionized gases and reactive gases. The electrons emitted from a stainless steel cathode ionize the impurity gases, and the ions are accelerated by the electric field between the cathode and the anode, and collide with the anode that is made of titanium, leading to the sputtering of titanium. As raw titanium is very reactive, the sputtered titanium gases easily react with the impurity gases, form non-volatile titanium compounds, and the formed compounds deposit on the wall of the pump casing; as a result, the impurity gases are trapped. A typical pumping speed is in the range of 50–500 ℓ/s. A titanium sublimation pump, sometimes called a getter pump, is based on the same chemical principle of gas entrapment, but the titanium is thermally sublimated. Although these reactive entrapment pumps are not very economically affordable, they provide an ultra high vacuum without any motion mechanisms and therefore shows high reliability. For these reasons, the sputter titanium entrapment pumps are widely used for analysis equipment such as electron microscopes. Sputtering phenomenon will be discussed later in Section 4.3.
X-Ray Photoelectron and Auger Electron Spectroscopy
Published in Grinberg Nelu, Rodriguez Sonia, Ewing’s Analytical Instrumentation Handbook, Fourth Edition, 2019
C. R. Brundle, J. F. Watts, J. Wolstenholme
UHV conditions are usually obtained in a modern electron spectrometer by use of ion pumps or turbomolecular pumps. Diffusion pumps, which were popular some time ago (Brundle et al., 1974), have now largely disappeared from modern commercial instruments. Whichever type of pump is chosen, it is common to use a titanium sublimation pump to assist the prime pumping and to achieve the desired vacuum level. All UHV systems need baking from time to time to remove adsorbed layers from the chamber walls.
Controlled preparation and vibrational excitation of single ultracold molecular hydrogen ions
Published in Molecular Physics, 2022
Christian Wellers, Magnus R. Schenkel, Gouri S. Giri, Kenneth R. Brown, Stephan Schiller
To achieve an ultra-high vacuum condition with a pressure below mbar, a turbo-molecular pump with a connection flange of 100 mm diameter and an ion pump with additional non-evaporable getter material is used. Additionally, a titanium sublimation pump is occasionally used to remove residual getterable gases and to enhance pumping efficiency. A shutter interfaces the mechanical pumps to the main system, allowing to shut them off, and thereby minimise disturbing vibrations. A quantitative analysis of the composition of the residual background gas is performed on a regular basis using a residual gas analyser.