Methods and systems for heating a tip apex of a charged particle source

A method, comprising:

• a) re-forming a tip apex of a tip of a charged particle source, comprising:
• i) heating a tip apex of a tip of a charged particle source;
• ii) detecting light generated by the tip apex while the tip apex is heated;
• iii) determining whether to change the heat delivered to the tip apex based on the detected light;
• and
• iv) changing a temperature of the tip apex in proportion to an amount of detected light;
• b) generating charged particles using the re-formed tip apex of the tip of the charged particle source without detecting light emitted by the tip apex of the tip of the charged particle source;
• and
• c) using the charged particles to investigate and/or modify a sample.

A method for operating a charged particle device, the charged particle device comprising a charged particle source having a tip, the method comprising:

• operating the charged particle device in a first mode of operation in which a charged particle beam generated by the charged particle source is directed to a sample through a charged particle optics to investigate and/or modify the sample, the first mode of operation being performed without detecting light emitted by the charged particle beam,
• operating the charged particle device in a second mode of operation in which energy is applied to the tip of the charged particle source,
• detecting light emitted by the tip, and
• controlling the energy applied to the tip based on the detected light emitted by the tip.