Ibrahim
Attached are the new set of BBSS TF measurement screenshots with slightly adjusted offsets applied. These offsets account for the Pitch drift we're seeing in F1 and for any other non-centered OSEM behavior due to temperature sagging. These are also the first TFs since moving the EQ stops back and re-confirming that nothing is rubbing or touching. See alog 79079 for the summary of what was done right before these were taken. Screenshot 1 shows the new offsets that are currently in. Screenshot 2 shows the old offsets that were from the OLV script - if the temperature stops varying to this degree, it may be worth reverting these.
The red trace are results as of today (07-12-2024)
The green results are results from earlier this week 07-10-2024, which were presented in alog 79032 had the issues mentioned in alog 79042 and alog 79036.
The blue results are the results from 01-05-2024, which we were using as a reference for expected coherence.
The new measurements are saved under a new file in the Data folder: /ligo/svncommon/SusSVN/sus/trunk/BBSS/X1/BS/SAGM1/Data/2024-07-12_1400_tfs. I've svn commited this Data file so it should be visible both in the X1 and normal workstations.
Interpretations:
The new transfer functions look much better than the ones from two days ago, meaning that moving the EQ stops back and adjusting for the Temp Driven sag was extremely fruitful. We can clearly see cleaner results, with almost eliminated noise in the previously problematic 1.5-6hz region and the results are markedly more coherent, comprable to the pre-rebuild state from 01-05. Now we can begin interpreting these results seriously with respect to the dynamic model, which I will leave for next week.
Next Steps (Next Week):
- Produce the BBSS Model-Result overlay comparison and look for cross coupling, unexpected resonances and other oddities.
- Make decisions about how to change the mechanical build or the parametric models for the BBSS
- Fix the M3 roll
- Discuss, then fix the M1 Pitch issue if it is still there an apparent
- If there's time, recenter OSEMs mechanically and set offsets back to their OLV values (since weather is going to be reliably around 100F all next week at the same times)
- Place a thermometer/temperature sensor in the staging building to track temp drift more accurately
