A clean set of TFs were previously taken for all stages (M1, M2 & M3) of MC1, MC3 & PRM (HSTS) suspensions (see LHO aLOG entries 12974 & 13019), to complete Phase 3a power spectra have been taken with damping loops both ON and OFF for all stages. These power spectra measurements have also been directly compared (allhstss_2014-07_28_Phase3a_H1HSTSs_ALL_Spectra_D*.pdf). The plot key is as follows:-

Black Dashed Line = Expected Sensor Noise
Blue Solid Line = H1SUSMC1 2014−07−28_1200
Green Solid Line = H1SUSMC3 2014−07−28_1300
Red Solid Line =H1SUSPRM 2014−07−28_1400

Summary:

Noise floors for MC1, MC3 & PRM are consistent with expectations. However, it should be noted that both MC3 & PRM M1 LF & RT channels exhibit excess noise around 10 Hz, which is most likely due to purge air flow.

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