After getting the interferometer locked again we had a productive afternoon and evening.  

• Jenne ran A2L after doing several of the ASC steps somewhat manually to get us locked (and later relocked).  
• Jeff did a pcal sweep, and later two actuation sweeps.
• Stefan changed the OMC ASC from the dither to the QPD signals, which has solved the saturation problems and improved the optical gain 45724  We also saw some down conversion of the dither lines when their amplitudes weer increased. 
• We spent 20 minutes undisturbed (for BRUCO or other things) starting at 22:42 UTC until 23:13 UTC.  However, there are lots of large glitches. There was nearly a 10 minutes period free of the large glitches from 22:54 until 23:13 UTC (Dec 5 2018).  The first attachment is a comparison of the DARM noise during this time compared to Nov 11th: the main difference seems to be slightly worse shot noise.  The rotation stage calibration has changed so that when we request 20W now we get 20W, before it was more like 22 or 23 W.  
• HAM5/6 scatter tests:
  • We did ISI injections on HAM5 ISI in all 6 dofs, with an excitation a factor od 10-30 above DARM from 10 Hz to 250 Hz we see nothing in DARM. 
  • Robert drove the OFI at 1 Hz in transverse to try to reproduce a scatter shelf seen at LLO.  We don't see a consistent shelf.
  • Robert also tried driving the OFI while the shaker was injecting a line at 80 Hz.
• Hang did a couple of ISI injections on ETMX.  He saw some coupling to DARM from the RX and RY, with a rough estimate of the ambient being a factor of 30 below DARM. This is the ISI which has excess motion in RX and RY, possibly due to a rubbing issue with the EFM.  
• In the guardian I moved the DARM loop reshaping earlier, (I moved the boosts from DC_READOUT to PREP_DC_READOUT).  This means there will be one less manual step for doing OMC scans in the future.  
• DCPDs:
  • Stefan and I changed the DARM offset and saw that this changes the DARM noise in a way that we don't understand. 45735
  • Stefan tuned the matrix elements used to construct DCPD NULL and sum. 45734
  • We also tried to switch the OMC whitening on including the low pass filter which is in the second filter bank.  We found that the gain for this filter was wrong by a factor of 2 compared to the gain in it's compensation filter, so we added a 2 to the compensation filter in DCPD B.   We transitioned DARM onto DCPD B, and saw that the frequency response of the compensation is also off by enough that we didn't want to keep DARM locked that way.  This filter change and the compensation is described here: 42361  We'd like to try engaging more whitening, but will try to get a better fit for that compensation first. 
• I transitioned the DARM control from the ETMX ESD to the ITMX ESD.  (the main purpose of this was to look at the broad shoulders on the 60 Hz line).
  • The attached script should make the transition if copied into a guardian shell (use caution).  
  • We were locked on ITMX ESD with the bias off but the HV driver on from 4:12 to 4:33 UTC Dec 6th, then I hit the button to turn off the high voltage driver at EX.  We were locked like that from 4:33 to 5:10 UTC. 
  • Robert connected some monitors to the voltage supplies for ITMX ESD before we did this transition, and also measured coherences with the EX supplies.  More details will be posted later, but the coherence at 0.4 Hz sidebands with the EX power supplies didn't go away when we turned off the bias on that driver.
  • turning on the ITMX bias to -437V caused a noise peak in DARM at around 57 Hz.  (see second attached screenshot), which had coherence with Robert's power supply monitors. 
  • Craig also looked at the EX electric field meter coherences while we did this. 45733