From desai@gravity.psu.edu Mon Jan  7 00:44:30 2008
Date: Mon, 7 Jan 2008 00:44:28 -0500 (EST)
From: Shantanu Desai 
To: Keith Riles 
Cc: John Zweizig 
Subject: Proposed DQ flag intervals for L1 BS optical lever problem in May 2007

Hi
Keith,
As you know L1 was glitchy around first week of May because of problems with
BS optical lever. Some notes on this can be found in the glitch enotebook
http://www.lsc-group.phys.uwm.edu/cgi-bin/glitch-enote.pl?nb=glis5gli&action=view&page=26

I have attached proposed L1 DQ flag intervals for this problem. I suggest
that +/- 2 seconds be padded around each of these intervals.
Since this problem persisted only for  a short period, these DQ flags  were
obtained in a "brute force manner" by looking at the second trends of
L1:SUS-BS_OL_SUM and looking for huge drops (which are easy to spot) for all
L1 segments between May 9 and May 11 (until the laser was swapped) and also
a few days before that by looking at some time intervals suggested by Dan
Hoak. One plot can  be found in the glitch enotebook entry above .  Of
course
these may not pick all the glitches.

Also there are some times (which I have indicated as "upward" in the
attached text file) where there were upward spikes (instead of drops) in
OL_SUM and I have cross-checked that all of these cause glitches in
DARM_ERR.


Anyhow let me know if you have questions. I have cced this to John , since
if I remember right, he was also planning on making DQ flags for all optical
lever glitches. Once all these optical lever flags
are produced, these L1 BS oplev flags can then be replaced. Until then ,
probably , these could be flagged.
Thanks
Shantanu

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