The back of a Helios. Main features are the two ion getter pumps pulling very low vacuum (10^-11 Barr) on the electron beam column. Replacing an electron beam source is a multi-day affair, but thankfully very little manual alignment is needed in comparison to older models. The alignments involve adjusting voltages on set of octopoles that manipulate the beam, ensuring the beam is straight.
Side profile of an ion beam column on a Helios. When troubleshooting ion columns, one major headache is checking the o-rings and crush rings on the bypass valves, which involves removing most of the ion column vacuum structure. All other options are exhausted before checking those.
Picture of tin balls. These are used to calibrate the electron beam for crisp imaging, since they have clean circles at varius sizes to test the full range of zoom.
Wide angle shot of a Helios with covers off. I noticed vacuum fluctuations while rough aligning the ion beam, which led to finding a rarely failed component. This saved shipping a new ion column and extended downtime for the customer.
Wide angle shot of a G4, a newer model. The service procedures are more automated on this model, but I did not see much of these in the field to take advantage of those features, sadly.
