A clean set of top-to-top TFs were previously taken for the ETMX (QUAD) suspension (see LHO aLOG entry 13134), to complete Phase 3a power spectra have been taken with damping loops both ON and OFF for all stages.

These power spectra measurements have been compared to previous in-vacuum measurements (allquads_2014-08-01_Phase3a_H1ETMX_ALL_Spectra_D*.pdf). The plot key is as follows:-

Black Dashed Line = Expected Sensor Noise
Blue Solid Line = H1SUSETMX 2014−01−28_1600, Phase 3b (in-vacuum)
Green Solid Line = H1SUSETMX 2014−08−01_1400, Phase 3a (in-air)

Summary:

Noise floors for ETMX are consistent with previous measurements. However, the LF and RT channels see features in the V DOF for both chains at ~7.0 Hz, ~15.5 Hz and 26.94 Hz, which were not present in previous measurements. Such features were also seen in recent TMSX power spectra too (see LHO aLOG entry 13151), and could be environmental, due to purge air pumps, clean rooms etc. and should be further investigated to ensure it's not baffle related.

It should also be noted, that the ETMX L2 UL channel exhibits excess sensor noise, as outlined in a recent aLOG entry (see LHO aLOG entry 13065). 

All data, scripts and plots have been committed to the sus svn as of this entry.