Charged Particle Beam System and Method of Operating a Charged Particle Beam System

A method of operating a gas field ion beam system, the gas field ion beam system comprising a gas field ion source with a tip having a terminal shelf with a predefined number of atoms and an extractor electrode, the method comprising:

• in a first mode of operation, operating the gas field ion beam system with a predefined voltage between the tip and the extractor electrode to generate an ion beam, and interacting the ion beam with a sample,
• in a second mode of operating, recording a field ion microscopic image of the terminal shelf of the tip in order to verify that the terminal shelf of the tip has the predefined number of atoms, and
• increasing the voltage between the tip and the extractor electrode in the second mode of operation compared to the predefined voltage to provide an electrical field strength of at least of 35 V/m at the terminal shelf of the tip.

A method of operating a gas field ion beam system, the gas field ion beam system comprising a gas field ion source with a tip having a terminal shelf with a predefined number of atoms and an extractor electrode, the method comprising:

• in a first mode of operation, operating the gas field ion beam system with a predefined voltage between the tip and the extractor electrode to generate an ion beam, and interacting the ion beam with a sample, and
• in a second mode of operation, recording a field ion microscopic image of the terminal shelf of the tip in order to verify that the terminal shelf of the tip has the predefined number of atoms and irradiating light to the tip, wherein the light level is at least 100 mW/mm2.