From raab_f@ligo-wa.caltech.edu Wed Apr 20 19:30:17 2005 Date: Wed, 20 Apr 2005 16:32:06 -0700 From: Fred Raab To: Glitch Working Group , keith , Justin Garofoli Subject: seismic triggers for data flags The web page http://www.ligo-wa.caltech.edu/~fjr/data_4k/ contains four ascii files of seismic triggers proposed for data-quality flags, generated using PSLmon with 10-sec strides and band limits tailored to mechanical resonances of suspended mirrors or the vibration isolation stacks. These files were chosen to cover the ends of the interferometers and the resulting triggers are known to have less than 50% false alarm rate in finding AS_Q events in the 70-110 Hz band that is typically excited by upconversion events in at least one of the Hanford interferometers. The triggers files give GPSstart GPSstop TrigValue as space-delimited columns. The file names indicate the trigger channels. The name 7H0EX0p4_0p9.txt indicate that the H0:PEM-EX_SEISX channel in the band from 0.4-0.9 Hz, with a trigger threshold of 7 times the median of the band-limited max trends from PSLmon. (H0EY indicates H0:PEM-EY_SEISXY, LVEAX indicates H0:PEM-LVEA_SEISX, etc.) (Band significance: 0.4-0.9 Hz covers suspension resonances of core optics 0.9-1.1 Hz covers suspension resonances of the small optics in the input optics chain 1.8-2.4 Hz covers the 2nd BSC vibration-isolation stack resonance) Fred -- Dr. Frederick J. Raab, Head LIGO Hanford Observatory P.O. Box 159 Richland, WA 99352 phone: 509-372-8125 FAX: 509-372-8137