Method for operating a particle beam system, and particle beam system

A particle beam system, comprising:

• a particle beam source;
• a source space;
• a sample space;
• an intermediate vacuum space separated from the source space and connected thereto via a first opening, the intermediate vacuum space separated from the sample space and connected thereto via a second opening;
• a first ion getter pump configured to evacuate the source space;
• a second ion getter pump configured to evacuate the intermediate vacuum space;
• a high-voltage source;
• and
• a controller configured to control the particle beam system to perform a method comprising:
• in a first mode:
• evacuating the sample space;
• operating the first and second ion getter pumps with the high-voltage source to evacuate the source space and the intermediate vacuum space so that a pressure in the source space is less than a pressure in the intermediate vacuum space and so that the pressure in the intermediate vacuum space is less than a pressure in the sample space;
• and
• measuring a current supplied from the high-voltage source to the first and second ion getter pumps and determining a value representing the pressure in the intermediate vacuum space based on measured current;
• and
• in a second mode:
• evacuating the sample space;
• operating the first ion getter pump with the high-voltage source to evacuate the source space without operating the second ion getter pump with the high-voltage source;
• and
• measuring a current supplied from the high-voltage source to the first ion getter pump and determining a value representing the pressure in the source space based on the measured current,
• wherein the particle beam system is configured so that in a measurement method a particle beam generated by the particle source and directed onto a sample in the sample space passes through the first and second openings.