Stuart A. Jeff K. Arnaud P.
Today, after HAM5 chamber closeout, we took tfs measurements on all degrees of freedom of SR3 and SRM, using dtt. The suspensions were NOT damped during the measurement. SRM looks healthy (cf first pdf, compared with last tf taken in may), but unfortunately we think SR3 is rubbing, looking at the V2V transfer function (3rd page of 2nd attachment, black curve). The first vertical mode at 1.07Hz is unexpectedly damped, and does not look similar as the previous tf taken on July 15th, after the magnet repair. We tried to run the same vertical tf applying offsets in different directions hoping to find a configuration were the resonance would come back to a high Q, but without any luck (cf screenshot). We will run long tfs overnight using matlab to make sure it's not some kind of measurement artefact (which we doubt), and see how it looks tomorrow.
We also noted SR3 M3 osem alignment UL is not ideal (cf 2nd screenshot), which might have been exacerbated by this morning's HAM5 ISI rebalancing.
Measurements were added to the sus svn :
-----------SRM-----------
Data/2014_07_21_1400_H1SUSSRM_M1_WhiteNoise_L_0p01to50Hz.xml
Data/2014_07_21_1400_H1SUSSRM_M1_WhiteNoise_P_0p01to50Hz.xml
Data/2014_07_21_1400_H1SUSSRM_M1_WhiteNoise_R_0p01to50Hz.xml
Data/2014_07_21_1400_H1SUSSRM_M1_WhiteNoise_T_0p01to50Hz.xml
Data/2014_07_21_1400_H1SUSSRM_M1_WhiteNoise_V_0p01to50Hz.xml
Data/2014_07_21_1400_H1SUSSRM_M1_WhiteNoise_Y_0p01to50Hz.xml
----------SR3------------
Data/2014_07_21_1400_H1SUSSR3_WhiteNoise_L_0p1to50Hz.xml
Data/2014_07_21_1400_H1SUSSR3_WhiteNoise_P_0p1to50Hz.xml
Data/2014_07_21_1400_H1SUSSR3_WhiteNoise_R_0p1to50Hz.xml
Data/2014_07_21_1400_H1SUSSR3_WhiteNoise_T_0p1to50Hz.xml
Data/2014_07_21_1400_H1SUSSR3_WhiteNoise_V_0p1to50Hz.xml
Data/2014_07_21_1400_H1SUSSR3_WhiteNoise_Y_0p1to50Hz.xml
Phase 3a DTT TF measurements continued for the lower stages of SRM as follows:- - SRM M2-M2 undamped results comparison (see allhstss_2014-07-21_Phase3a_H1SRM_M2_Doff_ALL_ZOOMED_TFs.pdf below) - SRM M3-M3 undamped results comparison (see allhstss_2014-07-21_Phase3a_H1SRM_M3_Doff_ALL_ZOOMED_TFs.pdf below) ISI Status: ISI unlocked, not damped, no isolation for the duration of these measurements. SRM alignment: Zero pitch and yaw offset. Summary: SRM L DOF TFs for both stages appear a little ratty, but this is most likely due to turbulent purge air flow in chamber. However, both lower stage TFs appear consistent with other H1 HSTSs and the model, therefore raising no concerns. All data, scripts and plots have been committed to the sus svn as of this entry.
Dont tell me SR3 is rubbing. Thats enough to crush my spirit today............I could of sworn I checked all EQ stops. And I dont remember altering any vertical ones on SR3...excpet ones below the IM mass and they are still a logn way away. *sigh*. My fingers are crossed for measurement artifact.