From gonzalez@lsu.edu Mon Jan 30 09:25:22 2006 Date: Sun, 29 Jan 2006 14:23:04 -0600 From: Gabriela Gonzalez To: Keith Riles Cc: Stephen Fairhurst , Daniel Hoak , Joseph A Giaime Subject: AS5 DQ veto segments Hello Keith, here is a list of time segments that should be flagged, probably something like "ASTRIGGER". The segments are at the end of science segments, and were found looking for the second trend channel L1:LSC- AS5_Q_MON.rms being below a threshold of 6e-4 counts: Dan identified the channel, Steve wrote the script to find the segments, I selected the segments from the results: a true collaboration from an operator in the control room to a theorist in ldas-grid!. Here a few more details on the results: * From looking at Shantanu's plots for block normal triggers, it looks like there is a glitch in the data before the servo reduces the AS5 signal, and in all cases I looked at, the glitch happens up to a second earlier than these veto windows, so I would pad them with an extra second. * There were other times within science segments where the channel was also below this threshold, but I only kept the intervals found at the end of science segments. This list includes the segment with two of the three loudest online BNS triggers (and probably many others, I haven't checked yet), in seg L1-249, which led me to start this investigation. * The end of the veto segment may be a second later than the end of the science segment because we padded the end to define the veto segment as a [star, end) interval according to the usual definitions, and maybe even 2 seconds off because of the difference between conlog and SegFind segments (we used SegFInd for the veto script, but I used conlog to find the segment numbers). The longest veto segment is 22 minutes at the end of L1-389, visible at hour ~ -2 in this FOM printed at 4pm on Dec 31: http://ilog.ligo-la.caltech.edu/ilog/pub/groups/detector/logs/2005/ images/12/31/scirun-1136066520.gif The operator log says: ---- 19:39 The AS Trigger has tripped although nothing appears to be going on with seismic. While we are out of science mode I am going to enter the LVEA to fill TCS X and Y chiller water. 19:48 Completed Filling TCS chiller water and have reset AS Trigger we are now back in science mode. (segment 390) ---- The time series shows the AS5 signal getting servoed below threshold at 19:25 in L1-389, so it seems the operator missed the fact that it was still science mode. The scimon, on the other hand, was wondering why the range was so low, but didn't realize that there had been an AS trigger.... The next segment had problems a few hours later with the end of the year and the leap second, but unrelated to the problems in this segment. I'm so glad the system is automated now... Let me know if you have any questions. I will document this for the glitch call tomorrow, and make an entry in the glitch notebook, if you want a reference for the data. Gaby. [ Part 2, Text/PLAIN (Name: "vetowithsegnums_edt.txt") 27 lines. ] [ Unable to print this part. ] [ Part 3, Text/PLAIN 6 lines. ] [ Unable to print this part. ]