J. Kissel, T. Vo

After a quick set of transfer functions on the ISI-ITMX showed more irregularities (see LHO aLOG 8653) after Thomas and I finished B&K hammering the Arm Cavity Baffle (see LHO aLOG 8656), Thomas an I went in again, first thing this morning, to investigate the baffle for signs of rubbing. 
We found nothing out of the ordinary:
- The baffle suspension is free,
- The eddy current damper's copper plate (which had caused problems before) were completely free of the suspended magnets, and the gap size was roughly 2-3 [mm]
- The the cable situation looked no different that when we had a clean set of ISI TFs.
We spend about an hour, moving things around, wiggling cables, ensuring things free by manually exciting things, but could not find anything that would cause such a drastic effect on the ISI. I attach the same quick transfer function that Seb took yesterday, 
BLACK shows the nominal result; what we expect to see if everything's peachy-keen.
BLUE shows the result just before we went into the chamber this morning. It indicates the same bad result [as expected, since nothing should have changed over night].
RED shows the result just after we came out of the chamber, having inspected the ACB. It's the same as blue, indicating that (a) we didn't change anything after messing around with the baffle (we were worried that just looking at the ACB's ECD system the wrong way would cause badness), and (b) we can't change the ISI result by messing around with the baffle (moving things around, shaking stuff, etc, etc, i.e. the ISI is rather insensitive to the baffle).

The important point we realized just as we were about to go into chamber: the other thing that happened between the noon (good) measurement of the ISI and the evening (bad) measurement of the ISI, was that the BSC dome was installed (see LHO aLOG ) After discussion with Sebastien, it makes much more sense that such a big operation is far more likely to have caused the badness that just tweaking / B&K hammering the ACB. The seismic team has now launched been launched on a thorough investigation. 

All apologies ACB, you're not such a bumbling oaf after all; maybe just a big, loveable, misunderstood, simpleton. HODOR.