Dan Brown, Alexei, Sheila, Nutsinee, Terry, TVo

After lunch we were able to get the PSL beam after the new PMC was installed and aligned,  Sheila adjusted the FSS gain to stabilize the loop and the IMC locked pretty easily after that.  We moved the mode cleaner optics pretty close to the alignment from February 8th when we had the X-arm peak.  Then we adjusted PR2 and PRM to flash PRX and MICH as well and got the beam down to HAM6.  The AS_A and AS_B centering loops converged pretty quickly and we offloaded the loop's control signal to the OM1 and OM2 alignment sliders.  We also closed the OMC_ASC loops and roughly offloaded to the OM3 and OMC alignment sliders.  

Before, when I closed the OMC angular loops, I didn't actually turn the integrators. But when I tried this time, it would push the beams off the QPD so after some hunting around I narrowed down the error to  a change in the phasing.  But I'm not sure where it came from.  Anyway, I added a negative sign in the POS_X gain filter bank and that seemed to make the loops converge nicely.  Not only that, the TEM01 mode in our new OMC mode scan was smushed down significantly, so we can get a more accurate mode-matching estimate.

Attachments:

• Alignment sliders
• OMC Mode Scan DTT Template
• OMC Mode Scan Data