Following the raising of the entire BBSS by 5mm (80931), we took transfer function measurements and compared them to the previous measurements from October 11th(80711), where the M1 blade height was the same but the BBSS had not yet been moved up by the 5mm. They are looking pretty similar to the previoius measurements, but there are extra peaks in V2V that line up with the peaks in pitch.
The data for these measurements can be found in:
/ligo/svncommon/SusSVN/sus/trunk/BBSS/X1/BS/SAGM1/Data/2024-10-31_2300_tfs/
The results for these measurements can be found in:
/ligo/svncommon/SusSVN/sus/trunk/BBSS/X1/BS/SAGM1/Results/2024-10-31_2300_tfs/
The results comparing the October 11th measurements to the October 31st measurements can be found in:
/ligo/svncommon/SusSVN/sus/trunk/BBSS/Common/Data/allbbss_2024-Oct11-Oct31_X1SUSBS_M1/
BBSS Status of Drift since moving whole BBSS up from the Top Stage to compensate for TM blades moving down (alog 809391)
Plots:
BBSSF1DriftPUMDoFsCurrentConfig: 6 day trend of LPY micron counts for the PUM.
- There seems to be a ~80 micron +YAW movement.
- Minimal (20 micron) drift in L.
- No P drift.
- There is no previous PUM screenshot because the flags were too low in the BOSEMs to be considered accurately sensing (which is one of the main reasons we raised the BBSS from the Top Stages to begin with).
BBSSF1DriftTMDoFsCurrentConfig: 6 day trend of LTVRPY micron counts for the Top Mass.
- There seems to be a ~80 micron in +YAW movement.
- Minimal (+40 micron) drift in P amounting to 6.77 micron/day of drift. No other drift.
BBSSF1DriftTMDoFsPreviousConfig: 18 day trend of LTPRPY micron counts for Top Mass.
- No drift observed. The 57 micron displacement in P amounts to 3.17micron/day of drift, which is neglibible.
BBSSF1DriftTMBOSEMssPreviousConfig: 18 day trend of BOSEM counts for Top Mass.
- No drift observed. The 196ct displacement in F1 amounts to 10.89ct/day of drift, which is neglibible.
BBSSF1DriftTMBOSEMsCurrentConfig: 6 day trend of BOSEM counts for Top Mass.
- Minimal drift observed in F1. The micron displacement in P amounts to 60ct/day of drift, which is slightly worse than prev. In general, this is about 6x more drift than the previous config, but 1/3 the drift of our past more drifty configs.
First Look Findings:
- There is a YAW drift in the current config compared with previous, which is somewhat understandable since blade movements at the top stage risk YAW displacement but why is it drifting and not just an offset?
- There is slightly more F1/P drift in the current config than the previous, but I would consider it largely minimal compared to the general amount of drift we've seen in other configurations.
