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Fri May 8 04:46:01 2009
BS/PRM/SRM table bad!
We went to center the oplevs because they were far off and found that (as usual) the numbers changed
a little after we carefully centered the oplevs and came back to the control room.
To see if the table was on something soft, we tried pushing the table: no significant effect with ~10 pounds of static force.
With ~10 pounds of vertical force, however, we saw a large change: ~0.25 Oplev units. This corresponds to
~20-30 microradians of apparent optic pitch.
In the time series below you can see the effects:
2.5 s: lid replaced on table after centering.
2.5 - 11 s: various force tests on table
11 s: pre-bias by aligning beams to +0.25 in pitch and then add lid.
So there's some kind of gooey behavior in the table. It takes ~1 s to
settle after we put the lid on. Putting the laptops on the table also
has a similar effect.
Please do not put anything on this table lid.