There was a drop in clean range around 5:20 this monrning, which doesn't seem to be a reapeat of the output arm shift we had earlier this week.
Attached is a trend of the DARM blrms (based on DARM error, no calibration corrections or cleaning) and comparison of the cleaned and corrected range against the CAL-DELTAL range, only the cleaned channel sees the drop. This made me concerned that we had a drop in optical gain, but the trend of the time dependent calibration correction factors doesn't show anything happening at this time.
I don't know what would cause a sudden change in the clean range, since I don't think that the jitter subtraction would cause a sudden change like this.
I'm still not at all sure why this drop happened, particularly if Sheila notes that there were no changes in the calibration TDCFs. However, the drop is seen in all of the GDS-CALIB_STRAIN channels, not just a drop in the _CLEAN channel. This indicates that the range drop comes from earlier in the process than the line subtraction or the cleaning.
The crosshair in the attached plot is the same time as the crosshair in Sheila's plot, just to make it a little easier to orient and compare the plots.
Blue: Range from CAL-DELTAL_EXTERNAL
Green: Range from GDS-CALIB_STRAIN
Red: Range from GDS-CALIB_STRAIN_NOLINES
Orange: Range from GDS-CALIB_STRAIN_CLEAN
