Sheila, Georgia, Craig

LSC:

This afternoon we had difficulty locking the interferometer, in part because we didn't have the same alignment as we had tuned the CARM offset reduction for.  Georgia and Jenne did an initial alingment that brought us back to a similar recycling gain to what we had sunday and monday evenings.  As soon as the control room quieted down and we stopped trying to use DRMI ASC the interferometer locked easily with the same guardian sequence and settings that worked earlier. 

We manually went through the steps in DRMI_ON_POP, but based on loop gain measurements (attached) we opted not to engage the MICH boost or turn the DARM gain up by the factor of 3.5 that the guardian would have used (we have been skipping a gain reduction by 2 step in the CARM offset reduction so this mostly comes out in the wash).

ASC:

We made some changes in the PREP_ASC_FULL_IFO, (it turned on PRC1 and PRC2 by mistake, and was missing a run state. Now it is turning the gains to zero.)  Now we are able to let the gaurdian proceed to this state.  We have been manually adding gain to DHARD P by engaging FM3 and increasing the gain to -30

We went to ISCT1 and found that the beam was falling off of POP X, so Georgia centered it.  We also found that the input matrix for DC6 was used for something else.  We should add the DC6 settings to the guardian to make sure they get set. 

We moved PR3 in pitch and saw that the signal was mostly in Q, so we shifted the phases by -90 degrees.  (When I accepted this in SDF I see that there are many phase changes in the ASC SDF, it might be helpful to accept them).  We checked this with an 8 Hz dither to PR3 M3.  After that we were able to close the PRC2 loops with the gain that is in the guardian.  They are only going to M1. We did not try engaging the integrator, but it should be fine.  

We checked that the lock point of INP1 looks good, and the pitch loop seemed to turn on fine with the gain of 1 that is in guardian, but yaw went in the wrong direction.  

I think that we the most efficient way to make progress is to find an alignment that gives us a better recycling gain before we try to use the DRMI ASC.  Our locking today started to go much more smoothly as soon as we stopped trying to use the DRMI ASC.  The easiest way to search for a better alignment would be to close more of the ASC loops in full lock and try moving spot positions.