Sheila, Kiwamu

We spent some time this evening to find the POP beam. We successfully found the POP beam and managed to extract it to ISCT1.

We realigned the down stream because we had touched PR3 to get the POP beam. Now REFL, POP and AS beams are all coming out of the chambers.

POP beam:

With the use of an analog camera, we became able to see the POP beam hitting the swiss cheese baffle in HAM2. It was too high and off toward left in the camera view. We temporarily placed the camera at 3 o'clock position at HAM3 spool. This allowed us for steering PR3 to get the POP beam coming out to ISCT1. Note that we could not see the spot with the GigE camera somehow.

We then placed an analog camera in the POP path on ISCT1. This is now blocking the POP beam opn the table, but serving as a reference. Also, touching ITMY, we got the Michelson fringing.

Re-alignment:

Since we touched PR3, we had to realign the downstream. We touched SR3 and SR2. We tried to center the beam on the left part of the SR2 baffle, but this resulted in DAC saturation in SR2 when centering the beam on SRM by steering SR2. So at the end, we gave up the centering of yaw of SR2 and brought it back to where it was. This released the DAC in SR2 as expected and we then could steer SR2 into SRM easily. We confirmed that the beam was hitting AS_A, _B and _C QPDs. The attached is the screenshot of the current alignment.

Since we are not super-confident with the SR3 alignment at this point. The HAM6 crews can feel free to revert the entire alignment, if they want to.