Sheila, TVo

In trying to figure out if the suspension's hysteresis effect has any affect on the response of the actuators, we attempted another pitch swing test on ITMX and compared the actuator-to-OSEM response before, during and after the swinging. This a continuation of alog-37915.

The setup was as follows:

-Before the test we had the ISI in a Fully Isolated state, with local damping on the SUS activated.

- During the test we had the ISI in Isolated Damped, with local damping off on the top mass.  We applied a range of offsets on the top mass pitch DoF with a .1 sec ramp time to emulate a short impulse, however, we found that we could not match the amount of motion seen by the earthquake and begain to saturate the DAC.

- After the test we had the same set up as before the test and the damping quickly smushed the motion. In general, we saw a 1.7 microradian DC shift after the test according to the optical lever and there were insignificant shifts in the OSEMs.  No noticeable changes to DARM or the BNS range. 

Attached are the PDFs of the responses and the time series and it's not the cleanest data but there aren't too many dramatic shifts in the response.