B. Bland, J. Garcia, J. Kissel

Attached are plots comparing the recent H1 SUS PR2 Phase 2B measurements against other HSTS in various stages (completing the data package) in order to give a final answer on Phase 2B testing.

As of this entry H1 SUS PR2 passes Phase 2b and is go for install into HAM3, with the following caveats:
(1) Late in the game, the assembly team found an IR filter is missing on an M3 (Bottom) stage AOSEM. The spectra comparisons show that there's little-to-no difference in the response of sensor, i.e. it's functional (as far as you can tell in the noisy chamber-side environment). Regardless, the assembly team are aware of the problem, and will replace that AOSEM once in chamber, as there's plenty of room to play around in there, and it's a simple fix.

(2) It's a long story (so I'll save it for a subsequent comment to this log), but we discovered the same small T to Y cross-coupling at 1.1 and 2.05 Hz on PR2 as was recently discovered on X1 SUS MC3. At the time, (we thought) X1 SUS MC3 was the only SUS that had such cross coupling, and (we knew we) still had lots of chances to debug the issue before install, so we approved his Phase 1b results and agreed to move forward. However, due to the hectic/scattered measurements and turn-on blips of getting the HAM SUS up and running at LHO, the cross coupling in H1 SUS PR2 (formerly X1 SUS PR2) has fallen under the radar up to this point. So, in light of several things:
- (As in seen in the attached TF comparisons, specifically pg 2, the M1 to M1 T to T TFs), ONLY X1 SUS MC3 and H1 SUS PR2 show this particular cross coupling, out of Nine other HSTS that have been built project wide (again further clues, a better zoom, theories, and conjectures to come).
- We will move X1 SUS MC3 chamber-side, and the install team will spend an extended amount of time identifying/debugging the problem where there's plenty of room, and less pressure. Once the problem is solved, they will retroactively make the same changes to H1 SUS PR2 in chamber, where (at least in HAM3) there's a comfortable amount of room to make adjustments.
- Again, the coupling is small, and goes away with damping -- the concern is the model, which we use extensively to predict motion estimates, may not be as accurate.
 
Ease of later documentation, the individual measurements that compose the rest of the package are aLOGged here:
Damping Loops OPEN M1 to M1 TFs: LHO aLOG 3851
Damping Loops CLOSED M1 to M1 TFs: LHO aLOG 3855
Amplitude Spectra of All Stages: LHO aLOG 3861