Georgia, Craig

Tonight we locked on ETMX by increasing the L2 LOCK drive to 30 from 15 again.  Sheila, Keita and Jenne have all been thinking about the DARM actuator stability, we decided to not duplicate their effort and try what worked last night.  We were able to reach NLN with the attached settings (attachment 1).

We retuned the MICH feedforward for our new actuator change.  The guardian now turns on MICHFF FM5 "Feb 21", the filter in attachment two.  If we return to a low PUM gain of 15, we will have to engage FM4 "Feb16b" instead.

Georgia measured the 9 MHz RIN coupling to DARM, and found it to be high again (like the green in attachment one of alog 47008).  This is after the original OMC PZT driver was reinstalled yesterday.

I tuned the front-end calibration for higher PUM gain and adjusted the DARM ERR gain from 1.2 to 1.177 to get correct shot noise.  Georgia shut the SQZ beam diverter to avoid the anti-squeezing we were injecting.  This got us back to low noise with no squeezing, with 83 Mpc range reported (which is actually around 90 Mpc with proper calibration).  The low frequency noise seems to be worse, this could be a result of the DARM actuator change not being properly calibrated, or real because of increased 9 MHz coupling.

A 7.7 magnitude earthquake hit.  We pressed the Really Big Earthquake button.