Baton Rouge: Giovanni Santostasi
     Caltech: Szabi Marka, Peter Shawhan, John Zweizig
     Carleton: Nelson Christensen
     LHO: Ben Johnson, Mike Landry, Steve Penn
     LLO: Gaby Gonzalez, Natalia Zotov
     Michigan: Keith Riles
     Oregon: Robert Schofield

S2 / S3 Investigation Reports:

• Calibration:
  
  
• Status and plans (Gaby Gonzalez, Mike Landry, Brian O'Reilly)
  The calibration team is working on the final S3 calibration with the goal of completion by the August LSC meeting. They are at the same time helping to validate Xavi's h(t) generation. The S3 calibration errors will follow later.A SURF student at LLO is working to improve the DC calibration precision there, which has been a problem in the past. At LHO, another SURF student [Evan Goetz, a soon-to-be Michigan graduate student :) ] is commissioning the photon calibrator.
  
  
• Time domain update (Xavi Siemens)
  No report.
  
  
• Data quality:
  
  
• Investigations: ( S2 , S3 )  & segment repository (S2 , S3 ) (John Zweizig, Keith Riles)
  John explained why a handful of short time segments Xavi had flagged as having unreliable calibration were not included in John's list that went into the S2 version 5 DQ segments. John had looked at those times manually and concluded that the apparently missing injection lines were actually present, but had not made it into the frames. The excitation channels are handled as test points, which makes their DAQ readback relatively fragile, in that the data gets shipped around an extra loop before recording.
  
  
• Update on low-order byte corruption in S2 (Ben Johnson)
  Ben has looked at the S2 data to see if the low-order-byte corruption affected AS_Q as rarely in that run as it did in S3 (see previous telecon minutes). The short answer is yes, corruption of AS_Q was apparently rare, based on looking at data-valid word corruptions, and more important, based on a mapping of the channel locations in the data block transfers where corruptions occurred. Ben did find one time period for LLO where AS_Q was hammered, but it was a day of  repeated DAQ reboots and will be DQ-flagged for that reason, anyway. In addition, Ben provided plots of examples of corruption in integer channels from S2,
  
  
• Timing (Szabi Marka, Daniel Sigg)
  Szabi provided a list of problematic intervals in S3 for all IFO's. The largest time flagged is for L1 where intermittent DCU synchronization errors were seen. It's not clear yet how serious such a failure is or whether other DCU crates without IRIG-B monitoring were likewise affected. Szabi will continue investigating and and will provide a brief writeup for the DQ repository with guidance to analysts.
  
  
• Glitches / Burst/Inspiral search group vetoes (Laura Cadonati, Erik Katsavounidis)
  No report.
  
  
• Violin modes (Sergey Klimenko)
  No report.
  
  
• Interchannel correlations: (Nelson Christensen, Sarah Vigeland)
• S2 .txt files ( H1 ,  H2,  L1 )
• S3 .txt files ( H1 , H2 , L1 )
  

Nelson summarized recent work on compiling lists of lines coherent between the IFO AS_Q channels and a variety of auxiliary PEM channels. There will soon be line lists, ordered by channel and by frequency. Nelson and Sarah are looking over a list of unknown lines that turned up in Szabi's GRB analysis. Peter Shawhan wondered why there were so many lines with strengths just above the threshold of 0.05 for coherenece and suggested they may be noise fluctuations. Keith suggested looking at histograms to understand the issue. Steve Penn suggested providing additional tables ordered by frequencies, but with varying thresholds. John Zweizig mentioned he has a handy utility for sorting on the DMT machines.

• Bilinear couplings (Steve Penn)
  Steve has a new version of BicoViewer which produces output from which movies can be created for later viewing. He is working at LHO with a teacher from a high school near his campus in New York and with an undergraduate. He will have a new demo to show at the August LSC meeting. Another new feature under development is heterodyning to speed up zooming in for fine resolution.
  
  
• Correlated inter-site environmental transients & local environmental disturbances  (Robert Schofield)
  Robert reported that an apparent excess in coincidental glitches in voltage monitors at the two sites has gone away; a script bug was found.
  He then gave an update on a variety of environmental disturbance mitigation efforts:
• The problem with pulsed air duct heaters looks as if it may be resolved by combining continuous heating with water cooling. The method looks promising, even on hot days. 
• At Keith's request, he has gone through all of the IFO elogs for S3 to determine time intervals when optical tables were entered and dust likely stirred up. He feels confident he has a good record for H1 and H2, but has e-mailed Rich Riesen at LLO to get corroborating information for L1 from laser entry logs. Gaby offered to follow up with Rich.
• The new $23K insulation kit for a test dewar does give the expected reduction by four in temperature fluctuations. Corey Gray has begun a "glitch watch" to see if glitches from that dewar decrease in rate accordingly.
• It was noticed recently that acoustic coupling into H1 had shot up to a factor of 10 above that in S3. The problem was tracked down to a backscattering beam dump that was a poor sink for IR.
• Optical levers seem to be causing more trouble. Sudden glitches lead to undesirable DC offsets. Rai Weiss is worried in general about EMI on these systems.
  

• Next detchar telecon:  Friday August 6 at 1:30 p.m. EDT  (S2/S3 investigations)