|PureGas is a modular gas handling system developed for applications such as high pressure SPM, high pressure XPS, catalysis or chemical vapor deposition, where a well defined flow of ultra pure gas is required.|
The systems are all-metal sealed as standard and fully Ultra High Vacuum (UHV) compatible. Due to the modular design, a wide variety of different gases can be handled sequentially or in parallel.
The purest gases commercially available contain about 10 ppm of impurities. At 10 mbar total pressure, this corresponds to a partial pressure of contaminants of 10-4 mbar. This might (and probably will) give rise to a monolayer of contaminants in 10 ms. Hence, surface science at elevated pressures requires additional gas cleaning to at least sub ppb levels. A prerequisite to reach such low contaminant levels is that the gas system itself is UHV compatible. The PureGas series allows the use of commercial gas cleaners for a wide range of gases. Due to the modular design, special requirements can easily be fulfilled. In addition to this requirement, the PureGas system is also designed so that all parts of the system can be leak tested with helium.
Handling ultra pure gases at high pressure is a challenge when it comes to the selection of materials. At high pressure, gases will frequently react with the wall material, or with impurities on the walls, and form volatile reaction products which are then deposited onto the sample surface. Gas mixtures at elevated pressures may also undergo catalytic reactions on certain materials, forming unwanted reaction products. Therefore, the choice of materials is of utmost importance, and must be made specifically for each gas. The Pure-Gas series has been designed with this in mind, and all materials are selected to be compatible with the particular gases in use.