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AdV-COM (AdV commissioning (1st part) )
mwas - 12:10 Tuesday 18 April 2017 (37281) Print this report
Comment to 6MHz modulation depth reduced -- DC readout for ~1 hour (37275)
Added the 56MHz path for the SSFS to the noise budget and analyzed the data at 21:38 UTC when DARM is locked on B1s2.

Figure 1, spectrum in terms of strain, at 10-20Hz the wide bump due to demodulation timing noise is gone, and the noise floor went down by a factor 10 from 1e-17 to 1e-18, but there is a prominent 17Hz line that was not present on April 6.
Figure 2, same but in terms of meter, noise in 10Hz-1kHz band is due to MICH (see figure 3), above 1kHz the noise follow the photon shot noise expectation (there is a 50% difference in the figure as the B1 DC gain as the B1s2 DC to DARM gain was not well adjusted in the noise budget model.
Figure 4, for MICH the noise budget doesn't show a clear culprit for the noise
Figure 5, for PRCL the noise is well explained by MICH below 100Hz and by SSFS above (see figure 6).

Figure 7 for the earlier data at 19:35 UTC, the dark fringe offset was larger (6mW on B1s2 instead of 4mW). With the corrected B1s2 DC gain the high frequency noise matches the shot noise, and the noise floor in the 10-50Hz band is lower, at ~1e-19.
Put the noise budget data for this last figure in /users/mwas/ISC/DClock_20170414.
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