Jim, Sebastien

For the past couple of days, we were seeing extra motion below 100mHz on the ITMX optical lever (especially in Yaw -> almost 1 microradian at DC)

Jim and I spent some time looking at the BSC-ISI, and finally ended up with a better configuration: the motion in Yaw has been reduced by one order of magnitude below 100mHz

New configuration:

- TSheila blends everywhere on ST1

- T750mHz blends on ST2. GS13s in high gain mode.

This improvement should be good enough for tonight. However, those are some premilinary results and there is still some work to do to fully understand what's happening.

It seems (this is just a guess for now) that we were reinjecting some noise by using the GS13s in low gain and  the wrong blends (too aggressive).  We'll have a better look at the ISI performance in different configurations tomorrow.

We also have to compare those results with the other chambers and see if we see consistency. Plus, it would be nice to work on damping the 0.7Hz resonance seen in Yaw.

Work in progress!