S2 / S3 Investigation Reports

• Data quality -  Investigations: ( S2 , S3 ) Segment repository (S2 , S3 ) (John Zweizig, Keith Riles)

KR made a last call for S2 and S3 data quality information before the release of S2 version 4 and S3 version 0 segments.
 
• Calibration (Gaby Gonzalez, Mike Landry)

Mike reported that since the last telecon a number of data products have been posted on the S2 calibration page, including framed versions of alpha, beta provided by Duncan Brown, and reference functions with and without notches for violin modes. The calibration team has also produced official S3 strain sensitivity curves available now on Albert Lazzarini's web page for archival figures. The team is trying to finalize its error estimates for S2 before the LSC meeting. It had been hoped to finalize S3 numbers on that time scale, but that's looking less likely now, as people try to understand differences in actuation calibration at low and high frequencies.
Much of the calibration team met recently at LLO with Martin Hewittson of GEO to try to finalize the time domain calibration method that Xavier Siemens and Bruce Allen have been working on. Xavier hopes to have a calibrated h(t) for all of S2 in 1-2 weeks.
 
• Timing (Szabi Marka, Daniel Sigg)

No update.
 
• Glitches / Burst/Inspiral search group vetoes (Laura Cadonati, Erik Katsavounidis)

The burst & inspiral groups are busy trying to finish up S2 analyses in time for the March LSC meeting. After many studies, the burst group has decided not to use any event vetoes in setting upper limits (but would look at vetoes in the case of a putative detection). The group looked hard at AS_DC for L1, but in the end the veto efficiency was only about 13% for a 4% deadtime. The group does plan, however, to use a short-epoch veto based on sustained (> 5 minutes) "growly" outliers in the 200-400 Hz AS_Q band. The inspiral group is looking hard at a POB_I veto which can give 25-30% veto efficiency for 3% deadtime. Nelson also mentioned that MICH_CTRL looked promising as a veto for the binary black hole search.
 
• Interchannel correlations   (Nelson Christensen)

Nelson has looked at H1-H2 coherence in AS_Q and coherence between each AS_Q and microphones. He confirms the expected dramatic improvement in acoustic isolation in both interferometers (see Robert Schofield item below). Some low-frequency spikes remain, however, and Nelson provides "zooms" of those features. Following a suggestion from Robert, Nelson is studying the strengths of the coherences w.r.t. microphones to help pinpoint coupling sites.
 
• Violin modes (S. Klimenko, J. Castiglione)

No update
 
• Bilinear couplings (S. Penn)

No update
 
• Correlated inter-site environmental transients & local environmental disturbances  (R. Schofield)

[e-mail from Robert,  slides shown at recent commissioning meeting]
Late-night work prevented Robert's attending the meeting, but he provided a link to slides he showed on acoustic mitigation at a recent commissioning telecon. In brief, his PEM injections during S3 confirmed a factor of 1000 improvement over S2 for H1. The most important acoustic coupling sites during S3 for the three inteferometers were
 
• H1:  Reflected port table, PSL table
• H2:  Dark port, reflected port table
• L1:  Reflected port table (or perhaps input optics table)

• Data Access (Peter Shawhan)

Peter reported that all archived data at the sites and Caltech is available via getframes (in LIGOtools), including reduced data sets and trends. A new version of the dataflow package has been released. The DTT can now see full and RDS frames. The S3 data access page has been updated with revised instructions. Rauha wondered how one could force the dataflow tools to get data from Hanford instead of Caltech. Peter said instructions could be found on the data access page and that the code is smart enough to look locally for data before looking elsewhere. Mike remarked that the new streamlined data access in the DMT works very nicely.

A.O.B.

• Next detchar telecon:  Friday February 27 at 1:30 p.m. EST (DMT software & planning for the E11 engineering run)