New SR3 offset: [452.9, -155.3].
There could be +-120-ish measurement error for YAW due to difficulty in finding the PR2 baffle right edge, so later if somebody gets suspicious about the clipping finer YAW scan of SR3 might be a good idea. This problem is not present for PIT.
New SR2 offset: [2800, 800].
Tolerance is +-100, but the center value strongly depends on the SR3 offset.
Since Doug is not available for finding the SR3 oplev beam with new offset, and since we use SR3 oplev for damping, we reverted SR3 and SR2 back to the original angle.
Tomorrow morning SR3 oplev will be done with Doug.
Plots will be posted later.
Initially:
SR2 [2963.7, 2728.0]. SR3 [430.3, 142.6].
Centered AS_C using SR2 offset: [2917. 7, 2794.0].
At this point ASC_SUM was [1576.29, 1576.87] (measured twice, each is 10sec average number).
SR3 scan on SR2 peanut baffle:
Position 1: [3042.9, -438.4].
Position 2: [-2137.1, -408.0].
Center = (Pos1+Pos2)/2 = [452.9, -423.2].
Then moved the beam to the right edge.
Position 3: [452.9, -1248.4+-100]. Barely touching.
Position 4: [452.9, -1848.4+-500]. Totally blocked.
For whatever reason YAW is much more ambigous than PIT to my eyes, and right edge is more difficult than top and bottom.
Right = (pos3+pos4)/2 = [452.9, -1548.4+-510].
Center-Right = 1125.2+-510 in the slider counts. This is supposed to be 36.75mm.
SR3-SR2-SRM angle is 1.67deg, and the baffle-SR2 distance seems like about 46cm (eyeballing HAM4 systems drawing), so the beam distance at the baffle is 17.5mm.
New beam position = 17.5mm/2 =8.75mm to the left of the center.
Y=-423.2 + 8.75mm/36.75mm * (1125.2+-510) = -155.3 +- 120;
NEW SR3 slider = [452.9, -155.3+-120];
At this point SR2 was moved to [2708.7, 814.0] to center AS_C, and the SUM was found to be [1596.99, 1597.84, 1596.48] (three measurements), this is about 1.3% increase from the initial number (but note below about the interference pattern caused by either some etalon effeft of a ghost beam from somewhere).
SR2 scan on SRM/Faraday:
Scanned SR2 in YAW, then in PIT, to find the Faraday edge while centering AS_C using Pico.
Today I made a finer scan than previously done (https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=15023) and what I originally thought to be a ghost beam looked more like an etalon type interference that mostly depend on the beam angle on AS_C. It was mostly in YAW but you can also see it in PIT, and the pattern is very repeatable.
Anyway, my objective here is just to place the beam at the center of the Faraday aperture, and I chose this:
New SR2 slider = [2800, 800].
More on the wavy pattern on the plot:
The peak-to-valley in YAW data is as large as 1.5% or so. Does this mean that SR3 scan before/after comparison is useless? No.
During SR3 scan, the beam was shifted by 300 counts in YAW, or about 10mm on SR2. The beam pointing on AS_C was fixed using SR2, so the beam angle on AS_C changed by about 10mm/18m or so, i.e. about 600urad or so.
OTOH, the full scale of the SR2 YAW scan corresponds to the Faraday aperture of 20mm, and that's roughly the beam shift on the pico. The beam position on AS_C was fixed using pico, and pico-AS_C distance is about 14 inches, so the beam angle change over the entire SR2 YAW scan is 20mm/14" = 60mrad or so. This is three orders of magnitude larger than SR3 scan angle change.
If we replotted it as the function of beam angle on AS_C (which I didn't), and put both the SR2 scan and SR3 scan data on the same plot, two data points representing the before/after SR3 scan would be basically on one vertical line in the plot. If this is indeed an etalon type thing on the diode surface, basically SR3 before/after the beam would see the same interference. That's my theory anyway.