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Agenda and Minutes, 16 June 2008

Agenda: Tues, 16 June 2008

We will meet with Adrian and Stefanos to discuss environmental correlations
and timing.


Attending: Virginia, Stefanos, Adrian, Warren, Robert

- Environmental correlations : high frequency magnetic fields in LVEA which
  couple into one interferometer and probably into both (Robert was only able
  to measure one). There are features in the spectrum from these - the features
  wander in frequency. This is at 37.5 kHz region - 75 kHz is worse. Robert
  suspect that these are VEM crate and power supplies. Robert would like paper
  to acknowledge this and account for it. There were no PEMs during S5 at this
  frequency, so it is a special case. Only 37.5 kHz being analyzed, 36,864 line.
  Robert wants a more detailed analysis of coherence - high resolution and
  broader band. Broader band can only be done with fast channel, quite
  difficult. High resolution is agreed to be a good idea. Coherence is clean,
  but what about canceling positive and negative contributions? Adrian says
  that changing phase of H1 acts in similar way to overlap reduction function
  and can be used to make argument of implausibility (as with H1-L1). Warren
  and Robert suggest that everything that can be done for this should be done.
  They also suggest trying to marginalize over possible cancelations of
  anti-correlated nois and correlated signal.

- Stefanos describes method of correlating FSR and ASQ. Warren wants to know
  why sinc function width is more than resolution. Is the line wandering? No,
  plot of phase differences between H1 and H2 0FSR shows constant phase diff to
  within 1 microsecond (distribution not explicitly plotted). Adrian points out
  amplitude variation calculation that we have not got to in review yet.

- Stefanos and Adrian will provide us a technical document with more of these
  issues discussed and clarified.
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