Present:

     Caltech: Szabi Marka,  Peter Shawhan, Stan Whitcomb, John Zweizig
     Florida: Sergey Klimenko
     Hobart: Steve Penn
     LHO: Dick Gustafson, Masahiro Ito, Mike Landry, Fred Raab, Robert Schofield
     LLO: Brian O'Reilly
     Michigan: Keith Riles
     MIT: Laura Cadonati, Mayur Desai
     Oregon: Ray Frey, Rauha Rahkola
     Penn State: Mike Ashley, Patrick Sutton
     UWM: Xavier Siemens

S2  Status Update Reports

• Investigation teams

 
• Data quality  (J. Zweizig, K.Riles)


John continues to run a saturation-detection monitor on the H1/H2 data, looking for ADC/photodiode saturation as inferred from the AS_Q channel and known filtering. The L1 search completed a while ago, but the sheer volume of LHO data has slowed the H1/H2 jobs. At best, the monitor runs at two times real-time. It's unlikely that the H1/H2 jobs will complete before release of version 3 DQ segments. On the other hand, the DataQual trends from all three IFO's are complete, and John expects to determine in the next two weeks conservative thresholds on glitch rates and band-limited RMS for throwing out data with a badly malfunctioning detector. That information will be provided in version 3 segments.

KR gave a brief update on the status of the DQ segment repository. Gaby has reorganized the segment-indexed trend plot pages and is looking at large AS_Q outliers. Doug Lormand has determined that, despite what we thought at the time, we had no working magnetometers in the LLO end stations during nearly all of S2, which means that we have no vetoes of very local magnetic disturbances (other magnetometers on site do provide vetoes of truly intercontinental magnetic disturbances).  Although a handful of scimons noted during the run that the EX magnetometer spectra didn't look quite right, the problem was not glaringly obvious because magnetometer channels and unconnected cables both display prominent 60 Hz combs. We should learn from this experience to ensure that PEM channels are checked out carefully before S3 and reliable reference spectra provided.

Planned for version 3 segments: cuts on DataQual glitch rates / band-limited RMS; cuts on calibration reliability, cut on known period of bad timing in LLO EY station, miscellaneous problems in H1/H2 already treated for L1 (e.g., end-of-lock noise degradation). Some discussion ensued on the LLO bad timing period, which was also characterized by nasty glitches. The consensus reached was to veto all of the LLO data between the time of a known power glitch, which is when it's believed the GPS antenna connection in EY was lost and the time when a backup antenna was connected. Brian offered to determine the GPS times for those events, and Szabi offered to look more closely at the start time to see if there is any confirming evidence of a timing problem starting then (e.g., an offset in the phase of a calibration line). Because the power glitch led to various locking troubles, the veto of the affected interval doesn't affect much science mode data. [Note added after meeting: Brian determined the approximate nominal start / stop times to be Mon April 7 17:00 UTC (GPS 733770013) and Wed April 9 7:06:32 UTC (GPS 733907204), corresponding to L1 segments 571-575, inclusive. The total science-mode data lost is 2821 seconds.]

Planned for version 4 segments: Cuts on inferred ADC/PD saturations in H1/H2, large violin mode excitations (see below). Additional information on artifacts found by the glitch investigation team may also be available in time for version 4.
 

• Calibration stability (G. Gonzalez, M. Landry, B. O'Reilly)


All point calibrations are complete for all three IFO's, and the curves have been provided to Patrick Sutton who will generate revised alpha/beta coefficients. Patrick estimates (fairly conservatively) that it will take a few days to determine where to make transitions from one reference curve to the next, and then another week or two to generate the coefficients themselves. He expects to have a full set of coefficients for all three IFO's within three weeks, to replace the curves and coefficients generated in real-time during the run.

There was some discussion of running multiple jobs to speed up the coefficient-generation step and of the scarcity of DMT machines that can see the full S2 RDS. John agreed to try mounting the S2 data (temporarily) on the LHO sand and stone machines to allow not only Patrick's jobs to run, but also reruns of glitchmon(Masahiro) and LineMon(Sergey) to occur. KR noted that the current bottleneck in rerunning DMT monitors on S2 data would be greatly relieved by support of DMT machines at the various Tier 2 computing centers (UWM, PSU, MIT). A proposal has been made to Lab and Collaboration management to organize such support.

In comparing the new calibration with the online version from S2, the calibration team finds a worst-case (H1) discrepancy of 20% and expects that if another (final) recalibration is done later, that its difference from the present calibration should be no worse than several percent. Because it may be another three weeks before coefficients for the present calibration are available, the team urges search groups wanting to get started on S2 analysis to use for now the online calibration, since it's already good at the 20% level. Xavier, who is working on the pulsar analysis, readily agreed to proceed using the online calibration and requested that ascii files of the coefficients be provided from the existing SenseMon trend frames. MikeL agreed to generated those files immediately. The calibration team also urges the search groups to speak up very soon if their requirements (e.g., binning, file formats) for S2 differ from those used in S1.
 

• Glitches (L. Cadonati, E. Katsavounidis)

Laura provided a summary of recent activity by the glitches investigation team. The MIT group is carrying on trigger mining in the H1/H2 data, using scripts developed in the S1 analysis. Triggers are being coarsely classified by dominant frequency band. Significant correlations in glitches are seen between AS_Q and  AS_DC, AS_I, MICH_CTRL, POB_Q for H1 and between AS_Q and AS_DC, AS_I, MICH_CTRL, PRC_CTRL for H2. Followup studies with glitchmon (varying thesholds) are planned. The Syracuse group continues its trigger mining of the L1 data, comparing DMT glitches with burst triggers. A detailed segment-indexed log is being kept.  The Florida group continues its WaveMon studies and has come up with a quantitative proposal for establishing "safe" vetoes based on correlated time/frequency clusters in auxiliary channels, where the auxiliary channels SNR must be above 5 and the ratio of the auxiliary channel SNR to the AS_Q channel SNR must be less than a ceiling. These studies are grounded by S2 hardware injections. The Oregon group is using glitchmon to study PEM couplings to AS_Q, again using hardware injections for reference. MikeA, John, Gaby, Nelson, and Natalia are working on various other investigations related to glitchiness in S2 data.
 
• Violin modes (S. Klimenko, J. Castiglione)

The Florida group will rerun LineMon over the S2 RDS to complete tracking of all known violin modes. Most, but not all, had been identified prior to S2 and tracked in real time. The group is interested in studying departures from thermal behavior, the slight non-linear dependence of harmonic mode frequency with harmonic number, and the vetoing of data segments with very high violin mode excitation. Stan urged that no veto be imposed unless there is saturation occurring or visible wings/shoulders on a given mode. KR suggested looking at sample starts of lock stretches to determine reasonable thresholds to set. Setting a threshold on, say, mean mode power being several times average thermal expectation would probably veto more data than is necessary.
 
• Steady-state correlations (N. Christensen)

Nelson reported by email. He and a student are studying correlations between AS_Q and optical level channels. Strong correlations are seen at 40 Hz, especially during glitchy periods (defined by high inspiral trigger rates).
 
• Bilinear couplings (S. Penn, V. Chickarmane)

Steve is working with a student to incorporate Vijay's definition of bicoherence (different normalization convention) into the BicoMon monitor. He is having some trouble in building the latest DMT version (2.6) on his apple computer at Hobart. (Patrick is also having some trouble with building on his linux machine. Both will talk John to sort things out.) Steve and Vijay are holding teleconferences every week to discuss progress. Vijay is working on a background DMT monitor to track known bilinear artifacts and hopes to be done by the end of July.
 
• Correlated inter-site environmental transients (R. Schofield)

Greg and Robert have made a trial combined RDS with PEM channels from both sites and are now putting together a complete version which is expected to be ready by early next week. Robert received a query from Ben Cusack in Australia who has been looking at magnetometer correlations between the sites and sees lines at 100 Hz and harmonics. These correlated lines have been seen before and are believed to arise from a DAQ converter box used in the coil magnetometer vaults at each site (Szabi).
 
• Local environmental disturbances (R. Schofield)

More progress has been made in acoustic noise mitigation at Hanford in regard to a redesigned periscope, new enclosures for the dark port tables, and fixes to single-wall HVAC ducts. Whether to add acoustic insulation to electronics racks or move them out of the LVEA has not yet been decided. Masahiro is looking at the acoustic couplings seen in S2 data and finds large variations in coupling strengths (factor of ~10) at different times. He cross correlates AS_Q with microphone channels. Robert, Nathan, Josh and Fred are using new a anemometer on the roof to study wind coupling to the IFO's and see a featureless 1/f contribution from 0.1 to 20 Hz. Corey has mounted three accelerometers on the large dewar to track down its infamous lock-disrupting glitches. KR wondered how much communication there is between Robert and Nelson on the optical levers and encouraged greater collaboration.
 
• Data access (P. Shawhan)

Peter had no news to report. KR suggested it would be useful to add an overview of all RDS sample locations to the data access page linked to the S2 web page. Encouraging people to provide missing documentation for that page would also be desirable.
 
• Data set reduction (I. Leonor)

No update.
 
• Signal injections  (S. Marka, P. Shawhan)

No new feedback from the search groups on hardware injections, but see Laura's burst report from the June 13 telecon.

A.O.B.

• Next Detector Characterization Teleconference: Friday August 1 at 1:30 p.m. EDT