What is Vacuum?
An essential requirement for the operation and analysis is that the instrument is kept under
Ultra High Vacuum (UHV). The vacuum is achieved and maintained by a variety of pumps: Rotary,
Turbo molecular, Ti-sublimation and Ion pumps. The condition of the vacuum system is
continuously monitored by an equal variety of vacuum gauges: Thermocouple, Penning, Cold
cathode and Bayard-Alpert gauges. The level of vacuum required is one of the highest of all
analytical instruments and requires extreme care with sample preparation and maintenance.
The vacuum in the analysis chamber can get down to 5*10-10 Torr. This is equivalent to
approximately 1010 molecules/Litre while air has 2.7*1022 molecules/Litre. Under these vacuum
conditions the probability of a secondary ion hitting a gas molecule within the instrument is almost