I moved the roughing pump out of the clean room, adding an extension hose.

This reduced a lot the vibrations induced by the pump. In the past when the pump was running we often saw very large noise, see the red trace in the figure below. Now, in the same conditions, we get the blue trace, which is much better.

The plot below shows a comparison of different configurations:

• blue: what I sometimes manage to get tewking the pump position and keeping it on top of a plastic box
• red: now, with the pump far away
• green: with the pump off

We are quite close to the pump off condition.