(Alexa, Daniel)
Continuing yesterdays work we locked on PRX and installed the beampspitter in the POP path in front of POPAIR_A. The beam was very weak and we had some fun aligning it. We needed an additional lens (ROC 500mm) to keep the beam small. After the beam combiner we measured 170nW of power. Another short focal length lens was installed after the combiner to focus the beam down. We are still missing a photodetector.
We have set up the ISCT1 ALS-Y-GREEN digital video camera (number 05 on the camera overview screen). We have left the CCD on the table in case we need it for any reason. We are still using the CCD camera for the x-arm, but the digital video camera is ready and in place when we want to swap that out.
I also brought BBPD (S1200247) from MY to ISCT1. The PD is mounted. Power and cables are still needed, but Kiwamu indicated we can borrow the 3f PD power from the legacy PD interface.
I have removed the CCD camera used for the y-arm beam and returned it to the shelves by the field racks.
I placed an ND06A (25±4% transmission for 1064nm) before the 50/50BS to reduce the power coming in from the PSL reference path. We also have a ND10A (10±4% transmission for 1064nm) readily avaliable (and it's an easy swap) if need be. The BBPD max incident power is 50mW for 1064nm. I have not measured the incident power yet.
Thanks to Stefan and Kiwamu, we got PRMI locked. This is much easier to work with :). I was able to do a rough aligmnet of the two beams by adjusting the BS. It remains to install the BBPD, but we have everything ready, so this should not take long and we should be able to finally do our measurement tomorrow.