Ultra high vacuum gauges require careful handling, particularly when being first installed and during early operation. Failing to take the proper care of the ion filament in the gauge will affect its capacity to measure pressure effectively and could also cause contaminates to enter the vacuum system.
Ion gauges contain a filament that can be removed and replaced when it reaches the end of its lifespan. When fitting a new filament, it is important to ensure that all surfaces are cleaned correctly and that all elements are kept clear of possible contaminates that could affect the ability of the system to reach its required vacuum level. In addition, proper positioning of the ultra high vacuum gauge head is essential. Incorrect positioning could lead to the grid short circuiting if the filament should sag or break during use. Similarly, incorrect positioning can also lead to the connector being pulled off the pins. New gauges need to be operated under the correct conditions to ensure that the filament reaches its longest possible life span and that the gauge as a whole achieves optimal results. The gauge filaments are under tension when they are new. Filaments should be run for a few seconds in emission to reduce and equalise tension. They should then be operated at a low emission current to ensure they are fully outgassed, before increasing the emission current. It is important not to subject the gauge to an electron bombardment degas until after it has been run at the highest available emission current and the resultant pressure burst has completely subsided.
Our Bayard Alpert ion gauges and components for ultra high vacuum gauges or UHV gauges all come with full operational instructions and guidelines on setup and installation. The Arun Microelectronics Limited team are also available to provide further support and advice at http://arunmicro.com/, whether you will also find our full range of UHV technology.