[Sheila, Karmeng]
We offloaded the saturation on ZM4 and ZM6 while maintaining the alignment to HAM6 QPDs.
Power budget: we measured 0.75mW at the OPO output, after SFI1, and after thin film polarizer. The power dropped to 0.74mW after BM3. And further to 0.71mW at the viewport/SQZT7 periscope and HD.
Scanned the IR and green transmission of the OPO, the green transmision (orange trace) will need further adjustmnet.
We spent most of yesterday and this morning recovering from the alignment shift that resulted from unlocking the VIP.
Yesterday Ryan Short joined us and we worked on the path from the VIP to FC. We now have the osems of FC1 and ZM2 (and ZM1yaw) back as they were in O4, and the beam centered on the iris right after ZM3. The beam should be aligned to the filter cavity since it is retroreflecting off FC1 and FC1 should be pointing to FC2. Since we only have the -Y door removed, we can't easily check the centering on ZM2 with a card; we set the alignment of ZM2 to match what it was in O4 and since the beam is centered on the ZM3 iris it should be at the position on ZM2 that it was in O4 (centered we believe). We also had to spend some time to make sure that none of the suspensions were close to saturation. While doing this we adjusted the pointing off the VIP using A:M1 and A:M2 (see VIP layout), which is why we had to readjust the co-alingment today, we also used A:M3.
This morning I made the final adjustments to get the beam centered on the ZM3 iris, and adjusted B:M4 to center the spot on the Z:M4 iris, and first iris on SQZT7, then also adjusted Zm4 and ZM5 to get the beam well centered on the SQZT7 irises. Kar Meng and I sent the beam into HAM6 and we were able to run centering servos to adjust ZM4 + ZM5 to center AS_A and AS_B, but this saturated ZM4. We then walked the beam using B:M4 so that it was a little high on the ZM4 iris (KarMeng has a photo 88859 to estimate how above center), but no suspensions are close to saturation.
Ryan Crouch ran OPO health checks, 88851, but wants to retake them with purge air turned down.
After lunch we readjsuted the co-alignment of the green and IR (photos in 88859), and re-alinged the seed beam onto the RLF QPDs, which was needed because of the shift when unlocking the VIP. With the seed beam we saturate the QPDs so we will need to revisit this and center using the CLF. We then took photos of various things in chamber as Kar Meng has added in 88859.
After all this we took one last peak at the beam going into HAM6, it was well centered on the AS_A, AS_B, and AS_C with our final alignment for about 30 seconds at 22:29:45, as shown in Kar Meng's screenshot. This means that we are done using the viewport.
Things left to do in HAM7:
- fine adjust alignment onto RLF QPDs (in laser hazard)
- get a good cavity scan to show alignment of IR and green into OPO (in laser hazard)
- dump beam going to OFI PDA
- remove irises
- unlock ISI + balancing
- repeat OPO suspension checks
The pump scan looks good ok the scope. The distortion from ndscope scan is most probably due to the filtering of ADC.
