Summary: Tonight we are able to lock reliably and stay locked with 60 Mpc range.

The noise lump that is coherent with the PSL Bullseye sensor is back.  We hadn't seen this since the vent, and I am wondering if it could be related to the PSL work today. 

• ALS to TR_CARM transition is now implemented in the gaurdian in roughly the way Jenne described it last night 36671.  In PREP_TR_CARM the ALS-DC_BIAS_GAIN is only ramped up to 24 (rather than 28) and FM4 in LSC-REFLBIAS is not engaged.  Then in TR_CARM the TR_CARM offset is set to -0.8 before the ALS-REFLDC_BIAS_GAIN is set to 28 and FM4 in LSC_REFLBIAS is engaged.  This has worked three times, and I have committed the guardian in the SVN as rev15704 (before I made any other changes tonight).
• I went through the steps in NOISE_TUNNINGS slowly, and found that the SRCL FF was making the IFO unstable. (This was the problem we were having last night when the INP1 ASC loop seemed to be oscillating at 1Hz)
• Trying to investigate why the SRCL FF makes the IFO unstable, I measured the MICH loop and saw that it's gain was too low so that the UGF was 8.3 Hz with only 13 degrees of phase. I increased the gain in LSC-MICH1 from 1.2 to 2 to bring the UGF to 12Hz where there is 20 degrees of phase. (measurement in attachment).  I saw a note in the guardian that a gain of 2 made the PR2 bounce mode ring up, so after I fixed the SRCL FF problem I reset it to 1.2 which seems to be OK, although we should probably take a better look at this loop sometime. 
• I switched the SRCL FF AC coupling filter to AC2 rather than AC (screenshot of the difference is attached), which made it stable.  I then adjusted the gains in both paths.  The final settings I found are in the 3rd screenshot, the 4th one shows the improvement in the DARM noise after returning the feed forward. 
• I increased the CARM gain by 6dB, bringing the ugf to 18 kHz.  This improved the noise from 90-40 Hz (5th screenshot).  I wonder if this is because of a non linear coupling through the OMC length.  
• Last, I used the PR3_SPOT_MOVE script to see if I could improve the recycling gain or reduce the jitter lump. I was able to improve the recycling gain, and I have reset the POP offsets (partially undoing the yaw move that Kiwamu made May 27th and almost completely undoing the pit move) This gives us a recycling gain of 29.6.  We could improve further by continuing to move in PIT, but run into the soft instability.

Notes for whomever next locks:

The guardian can be used as is to get to REDUCE_RF9_MODULATION_DEPTH.  For now we need to manually skip SRM_ASC_HIGHPOWER, do NOISE_TUNNINGS as it is written in the guardian, and skip CLOSE_BEAM_DIVERTERS.  The next things I would try are to explore a little more with POP spot position (usig PR3 spot move) and soft offsets to see if we can reduce the jitter lump, or improve the recycling gain.  The 6dB increase in CARM (LSC-REFL_SERVO) IN1 gain is not in the guardian, it could be done manually about 20 minutes after locking.  It might be necessary to run an initial alignment after all the alignment changes I have tried.

 I have crashed 3 computers in a row tonight.  Is this because of sometime that happened during maintence day?