When imaging in your SEM do you ever experience jagged lines on the edge of your image at high magnification?
Most electron microscope users have experienced this. In fact in most cases it is unavoidable. There can be multiple sources that can cause this type of interference. The first can certainly be that your environment is out of specification. EM fields, vibration and acoustic noise from the environment can cause interference. In our experience when observing the EM specialists that know their craft in addressing these issues (we call them "Mitigation Specialists") it never seems to always be one thing. Invariably there are multiple of sources that contribute to these aberrations.
The fact is the majority of us do not have TITAN or ARM TEM systems that require 1 angstrom performance. Nor do most of us have the budget necessary to mitigate our environment. That said, there are cost effective ways to address some basic issues of acoustic and vibration interference that may come from your vacuum rotary pumps. The first is to use rubber dampers on the bottom of your rotary pumps. Dampening the bottom of the pump may prevent the vibration from being transmitted across the floor.
The second is a full enclosure for your system that is shown above. It is important that your enclosure have a temperature sensor and is well ventilated and thoroughly tested as EDWARDS does with their approved enclosures.This approach is more expensive, though the enclosure will certainly address the vibration as well as any annoying acoustic noises in the room. In the end if you are someone who is sitting in front of the system all day, then you should try to make the environment as tolerant as possible.