Discussion on Interferometer Diagnostics

1
Discussion on Interferometer Diagnostics

• Gabriela Gonzalez and Peter Saulson
• LSC, 17 March 2001

LIGO-G010140-00-D
2
Why Interferometer Diagnostics?

• To learn criteria to reject an apparent
  gravitational wave signal as an instrumental
  artifact.
• (Of course, coincidences between interferometers
  are also very powerful!)

3
Goals of this discussion

• 1) Share ideas on strategies across UL groups
• 2) Find common aspects of plans, especially for
  the work that is preparatory for E6
• 3) Set up work plan, with shared labor, if
  possible.

4
Common ideas

• 1) List of key diagnostic channels
• 2) Homework to do before E6
• 3) Constructing vetoes
• 4) Using vetoes
• 5) Diagnostic software

5
Common idea 1List of key diagnostic channels

• Internal ifo signals and PEM signals
• Inspiral group already has a draft list
• (It is long, could use prioritizing.)
• Signals will be handled differently,
• depending on strength of transfer function
  between measured variable and GW channel

6
Common idea 2Homework due before E6

• We need an achievable, prioritized list of
  measurements to make on each channel.
• Wish list
• transfer function to GW channel
• measured, calculated, or estimated
• noise level, spectrum, stationarity/gaussianity,
  cross-correlation with GW channel
• spectral lines (strength, stationarity, )
• non-linear saturation, lock loss, bilinear noise

7
Common idea 3 How to make a veto?

• Actual vetoes will be search specific
• At future discussions, look for commonalities

8
Common idea 4How to use vetoes

• Probably pretty similar for time-domain searches
  (inspiral and burst)
• generate (search-specific) veto channel
• re-examine diagnostic channels after
  identification of candidate signals
• relation to coincidence test
• which is more powerful/useful?
• applied in which order?
• How similar in freq.-domain searches?

9
Common idea 5Diagnostic software

• DMT monitors that are almost ready
• UL groups and DetChar Group need to talk more to
  refine list, give each other feedback
• New monitors
• LDAS/LAL code
• post-processing code
• and ?

10
Coordinating our work

• Who is available for these tasks?
• How to organize?
• individuals babysit particular channels?
• How to coordinate work?
• across Upper Limit groups
• with Detector Characterization
• visits to sites!
• How to document results in usable form?