stefan.ballmer@LIGO.ORG - posted 15:49, Wednesday 16 September 2015 - last comment - 15:40, Thursday 17 September 2015(21552)
So called dust glitches, some examples
Attached is agallery of 5 "dust" glitches. Still clueless of what they are, but - ETMY saturation is a symptom, not a cause - it is not possible to produce such a white glitch from saturating a drive. - The DCPD spectrum shows a roll-off for all of them - But the roll-off frequency (i.e. glitch duration) varies significantly = from about 300Hz to 3kHz. Example 2: GPS: 1126294545 UTC: Sep 14 2015 19:35:28 UTC ETMY saturation: yes Example 3 GPS: 1126437892 UTC: Sep 16 2015 11:24:35 UTC ETMY saturation: yes Example 4 GPS: 1126434798 UTC: Sep 16 2015 10:33:01 UTC ETMY saturation: yes Example 5 GPS: 1126441165 UTC: Sep 16 2015 12:19:08 UTC ETMY saturation: yes Example 6 GPS: 1126442379 UTC: Sep 16 2015 12:39:22 UTC ETMY saturation: yes
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WIth Hang's help, I managed to investigate these glitches with the new lockloss tool using SUS-ETMY_L3_MASTER_OUT_LL_DQ as a reference channel. The script couldn't find any other optics that glitch prior to the ETMY. And sometimes the glitches are seen by ETMX 30-40 miliseconds after.
I've attached the plot of the glitches at the time you've given. I've also attached the list of channel I told the script to look. Basically all the SUS MASTER OUT DQ channels. Please let me know if you have any suggestions on whereelse I should look at.
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Attached are time traces of the DCPD_SUM for the 5 examples.
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