J. Kissel

Figured I'd make the same in-air vs. in-vac comparison of the whole 6 x 6 transfer function matrix for H1 SUS PR3 like I did for SR3 in LHO:83831.


                 D R I V E   D O F 
          L     T     V     R     P     Y

     L    --    meh   meh   meh   eand  YI
 
R    T    meh    --   nd    eand  meh   meh
E 
S    V    YI    YI    --    nd    meh   nd
P
     R    meh   eand  YI    --    YI    meh
D 
O    P    eand  YI    YI    YI    --    nd
F
     Y    YI    nd    nd    nd    nd    --

Recall the legend is 
  YI = Yes, Interesting. DC response magnitude is a bit different between vac and air, but not by much and all the resonances show up at roughly the same magnitude.
 meh = The resonant structure is different in magnitude, but probably just a difference in measurement coherence
eand = The cross coupling is expected, and not different between air and vac.
  nd = Not Different (and unmodeled). The cross-coupling is there, but it doesn't change from air to vac.

(1) For some reason, the data quality on the upper diagonal is worse for the PR3 in-air TFs vs. SR3's but better on the lower diagonal. The "mehs" in PR3's cases are more "man, I wish the coherence was better so we could make a better statement."
(2) For the most part, the same DOFs that are "Yes, Interesting" for PR3 are "Yes, Interesting" for SR3.

Needs a more careful study, but we're only looking at crappy in-air vs. good in-vac data because we're vented right now, and we want to see if it's sensible to measure these things in air, fit the data, and trust that that fit will work in vacuum. 
Given that we're seeing *any* of these elements as "Yes, Interesting -- there's a difference between in-air and in-vac" means that we're getting scared away from do that -- the problem is hard enough! We'll probably just end up waiting for the SUS to be back at vacuum in a few weeks.