Tag Archives: ion pump

Ion Pump

 

The ion pump is a high vacuum pump that is based on ionizing the gas. When the gas that enters the ‪#‎ionpump‬ it always has some ions in it and those are pulled towards the titanium cathode. These ions are then trapped between the titanium atoms and they may also chemically react with titanium forming solid titanium nitride or titanium oxide, depending on the gas. In addition electrons and titanium atoms are emitted from the cathode when bombarded by the ionized gas molecules. These electrons are then accelerated towards the steel anode as the potential between the anode and cathode is thousands of volts. A magnetic field caused by the magnets makes the electrons move spirally so they spend more time in the open and more likely hit gas molecules to ionize them. The generated gas ions move again towards the cathode and kick out even more electrons and titanium atoms. Some of the kicked out titanium atoms also deposit on the anode and in this process bury gas molecules under them. The pump may work for several years if used in high vacuum environment and if the amount of pumped gas is not large. At some point however the cathodes need to be replaced.

Vacuum Systems and Technologies

Vacuum can be understood as space from where matter (for example air) has been removed. It naturally exists in outer space but for certain applications, like materials characterization techniques, it needs to be achieved artificially. The desired level of vacuum is obtained with the help of a suitable vacuum pump. For example low vacuum (low quality vacuum with higher pressure) can be generated with a diffusion pump, scroll compressor pump, rotary vane pump, diaphragm pump or a sorption pump. High vacuum (high quality vacuum with very low pressures) however, can be obtained with high vacuum pumps such as the turbomolecular pump, ion pump, titanium sublimation pump and cryopump. The level of vacuum is measured with devices called vacuum gauges (vacuum meters) like the thermocouple gauge, pirani gauge, penning ionization gauge and the quadrupole mass spectrometer (analyzer). The working principle of vacuum pumps and vacuum gauges is explained with 3D animations in the video lecture above.