Terry M, Sheila D, Nutsinee K, Daniel B, Thomas V, Alexei C

This morning Terry and I went to HAM6 to co-align the squeezer beam to the single bounce beam that we had aligned last night.  This went pretty smoothly using the OFI pico.  The attached screenshot shows the OM alignment based on offloading the AS centering loops with the single bounce beam, and the ZM alignments needed to get the OPO seed beam onto the AS WFS. We also measured the power in our seed beam right after the beam diverter and arriving on the other side on HAM6, we found 67% of the power injected into HAM5 returning to HAM6, but we need to recheck the offsets on the power meter for this measurement. This allowed us to get some decent OMC mode scans using the OPO beam.  Thomas and Dan are writing alogs with results from those scans, the main message is that our results from the beam profile (mode matching of about 80%, we aren't able to fix it using the translation stage) are confirmed by the OMC scans.

Having this co-alignment fixed means that we are finished using the PSL beam in HAM6, and should not need it again before we put the doors on.

Our first OMC scans with the seed were noisy, so Terry Nutsinee and I went back to HAM6 after lunch and reduced the green power from 3mW in reflection to 0.3mW, and increased the analog gain on the OPO servo board from -3dB to 17 dB. We also increased the temperature from 43.25C to 43.35 C to compensate for the lower green absorption in the crystal.

Details of co-alignment: 

OM1 P 51 Y -265 OM2 P -225 Y -458 ZM1 0 P 0 Y  ZM2 0 P 0 Y

SRM 1845 P -2461 Y (alignment that we found with SRX last night) squeezer beam 6 mm in - x direction from IFO beam at entrance to chamber near OM2 structure. 

SRM 1933 P -2239 Y (alignment from Feb 8th)  squeezer beam move about 45 degrees -x side higher than ifo beam, still about 6 mm distance. 

Moved OFI pico down from -1898 to -3619 counts, yaw +1100 counts (to end at -1200 coutns).  Beams overlap entering HAM6, at OM1 sqz beam is too high by 2 mm.  Tried moving SRM P to 1845, saw beam get closer at OM1, undid SRM move, moved ZM2 P to +350 (counts not urad), beams look overlapped on card at OM1, moved ZM2 to 950 counts to overlap at OM2.

Measured beam entering HAM6, 0.30 mW, closed beam diverter measured beam arriving on SQZT6, 0.445 mW. 26.5 mW of seed out of fiber collimator.