A clean set of TFs were previously taken for TMSX (TMTS) suspensions (see LHO aLOG entry 13140), 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 (alltmtss_2014-08-01_Phase3a_H1TMSX_ALL_Spectra_D*.pdf). The plot key is as follows:-

Black Dashed Line = Expected Sensor Noise
Blue Solid Line = H1SUSTMSX 2014−05−09_1800, Phase 3b (in-vacuum)
Green Solid Line = H1SUSTMSX 2014−08−01_1100, Phase 3a (in-air)

Summary:

Noise floors for TMSX are consistent with previous measurements. However, it should be noted that both LF and RT channels see features in the V DOF at ~7.0 Hz, ~15.5 Hz and 26.94 Hz, which were not present in previous measurements. These could be environmental, due to purge air pumps, and clean rooms etc. and should be further investigated to ensure it's not baffle related.  

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