1. IM4 and IOO PZT

Before doing anything the beam was already coming to the OFI. We centered the beam on OFI input aperture using BS just so that it's easier for us to eyeball the beam motion.

We removed the PIT offset just enough so that the output wouldn't rail and IM4 is properly damped. (This happened to be the slider MEDM limit of -25000.)

We used IOO PZT to bring the beam back to the center of OFI input.

2. SR2-SRM-OFI

We used BS to center the beam on SR2, then used SR2 to center the beam on SRM. Centering accuracy claimed by Siddhesh??, Brijesh??, JeffK, and later confirmed by Koji, is a couple of mm on SR2 and less than a mm on SRM.

The beam was off in PIT by negligible but measurable amount (0.5mm) on the input aperture of the OFI, but a couple of mm too low on the output aperture.

Gerardo adjusted the OFI SUS to lower the output side of the OFI and it's within 0.5mm for PIT on both the input and output of OFI, but a mm or so in YAW at the output. This might sound small to you but we'll fix it for the reason explained in 4.

3.  OFI-OM1 craziness of O1/O2 seems to be gone, but this means that the septum window needs to be rotated (again).

We found that the beam on OM1 was about 9mm too high and 12mm off to the side. See Koji's attachment to this log.

Back in the day before O1, the beam was 10.6mm too low on OM1. (alog 13391)

Again back in the day, to fix this craziness the septum window needed to be rotated by 120 degrees clockwise, and this got the beam back to the right height on OM1. (alog 13477)

Changing the Faraday (or maybe something else) should have fixed the root cause of the craziness. But this means that the septum window should be rotated back by 120 degrees counter-clockwise. This will set the septum plate angle as designed, the beam height on OM1 should become about right.

OM1 position should be also shifted sideways to accommodate the yaw change caused by this. Which means that the OM1 and OM2 alignment needs to be mechanically moved in YAW.

4. OFI-ZM2 alignment is totally wrong, OFI YAW alignment should be revisited. 

Right now, when we install the additional HWP, the rejected beam from OFI is blocked by the Faraday rotator. The beam is not centered on the first steering mirror in YAW to start with though it's not clipping, it's close to the edge of the the second steering mirror, and the reflection from the secod mirror directly goes to the rotator.

We could adjust the steering mirror position and angle and be done with it, but Koji felt that we should align the OFI in yaw before moving the steering mirror, especially the position of the mirror mount.

Tomorrow.

I will NOT transition LVEA to laser safe tonight.