Sheila, Matt

We wanted to see if there was anything interesting in the voltage between the ESD cable grounds and the chamber grounds (similar to tests done at LLO), so we installed a couple of SR560s which we clipped to the ESD grounds and the chambers at both end stations.  The SR560s have a gain of 1000 and a LP at 10kHz.

A little coherence with DARM is seen around 280Hz and 140Hz (see image).  Robert says that these are likely to be due to fans.

These SR560s can be recovered whenever someone is next at the end stations (we don't  want to disturb the BRSs at the moment).