Borja
I just came back from a quick visit to End-X (UTC 2014-08-27 00:25:00).
I took some pictures (see attached) at the feedthrough wiring for the ESD at BSC9 (ETMX chamber). I compare it with the ones I took a while back at ETMY (see attached).
There is an obvious difference, the red insulating tape at ETMY wiring which does not show at ETMX. The wire which has the insulating tape carries VBIAS to the ESD at ETMY. The reason for the insulation is that the coax cable's shield is cut off because the corresponding coax cable inside the chamber has the known issue of having the shield connected to the center lead. This problem is non existen at ETMX.
This is another big difference between both masses which may be related to the more stable results on the charge measurements observed at ETMX.
We need to fix the shielding in any event. The shield now acts as a large capacitance coupling of the electrode to the chamber and will inevitably cause cross talk and noise in later operations.