Ion vacuum pumps are high-performance pumps with industrial use. These pumps are also known as sputter ion pumps or ion getter pumps. The ion vacuum system can produce an ultra-high vacuum without any valves or moving parts. This invokes curiosity in people, and many want to buy them. Here are a few essential things that you should know before purchasing sputter ion pumps.
These pumps require a large magnetic field in an isolation chamber. It uses high voltage to pull electrons into pump assembly. The pumping process depends on three methods –sputtering of the getter materials inside the chamber made of series of cells.
The burial of produced ions (chemisorption) and implantation (physisorption) plays an important role in the pumping process. The gas molecules that are gained through chemisorption and physisorption are permanently bound. However, they cannot contribute to the pressure inside the chamber. This whole process can be separated into four stages of operation.
Different Stages of Operation
Stage 1- High Magnetic Field
These vacuum pumps have large magnets fitted outside the vacuum, generating a 1200 gauss magnetic field. The magnets guide the electrons within circular anode rings.
Stage 2- Plasma
It involves the generation of plasma. The pump uses different methods to remove gas, and high voltage is enforced on the element assembly. This action pulls ions electrodes in the anode assembly where they revolve in a cloud referred to as plasma. The pump traps plasma in the magnetic field.
Stage 3 – Gas Molecules
When the gases move in the anode assembly, they are struck by electrons. The collision causes the gas molecule to break, and it loses an electron leaving behind a valence shell. Now the gas-only has a positive ion. The gas molecule is forced out of the anode tube by the high voltage filed with high speed. The gas molecule, which only has a positive ion, is pushed towards the cathode plate.
Stage 4 – Gas Ions
When a positive ion is forced towards the cathode plate, it causes sputtering. The next step involves cathode materials pushed towards the anode tube. The positive ion reacts with cathode material physically and chemically.
Different Types of Ion Getter Pumps
There are three types of ion getter pumps. Though they work on the same principle, the primary difference between them is the cathode material used. The three types of pump are
- CV/Diode pump – the cathode material used in this ion pump is titanium. These pumps have relatively lower pumping speed for noble gases.
- DI/Noble Diode pump – the cathode material used in this pump is tantalum. It works better with noble gases.
- Triode pump – the cathode material used in this pump are negative voltage titanium rings. These rings are grounded.
The Ion Getter Pumps are used in general ultra-high vacuum systems like surface analysis, molecular-beam epitaxy, and high-energy physics. Some of the reasons for using ion getter pumps are
- Highly resistant to magnetic field and radiation
- 100% Hydrocarbon free
- Operates even at high temperatures
- No vibrations as there are no moving parts
Ion pumps have no maintenance requirements, which make them popular for various industrial applications. The post covers essential information about ion pumps that can help you make an informed decision.