oli.patane@LIGO.ORG - posted 18:10, Thursday 25 June 2026 - last comment - 09:26, Friday 26 June 2026(90765)
BBSS P to Y as compared to BSFM
Arnaud, Marie, Jeff, Oli
Compared to the BSFM, the cross coupling in the BBSS from P to Y is mught higher (This plot shows ~ 2 orders of magnitude, but I don't want to confirm that yet since the data fudge for the BSFM might be incorrect).
I made a comparison of the last few BBSS P to Y measurements and compared them to an old BSFM P to Y measurement.
We found that the P to Y cross coupling looks a lot like just Y to Y (bright blue), so there is much more Y than there should be.
There is still some more work to be done to absolutely confirm this, but current in progress results can be found in /ligo/svncommon/SusSVN/sus/trunk/BBSS/Common/Results/comparetripleparams/2026-06-25_BBSSvsBSFM, r13050.
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A minor grain of salt: though the "(BBSS Teststand BOSEMs * 0.35587 | P to Y)" BOSEM data set seems to report *equal* if not *worse* P to Y magnitude as Y to Y magnitude, the data quality is garbage -- likely incoherent at all-but-on-resonance frequencies.