1. S2/S3 Glitch Investigation Update
Laura Cadonati
for the Glitch Investigation Group
LSC meeting, Livingston
March 17, 2004

2. Wrap-up of S2 Glitch/Veto Search
Large number of channels analyzed for veto search
Inspiral group:
adopted as veto L1:LSC-POB_I 70 Hz HP
Burst group:
no veto adopted for upper limit search
favorite candidate was AS_DC (non-linear coupling with AS_Q at all three interferometers, esp. at L1)

3. Inspiral Veto: L1:LSC-POB_I (N. Christensen, G. Gonzalez, P. Shawhan)
a selected playground segment
the worst playground segment
Dead time = 3%
Veto efficiency = 11% at SNR>8

4. Non-Linear Coupling AS_DC - AS_Q (R. Adhikari, S. Ballmer)
At all three IFOs, burst candidate events best correlated with glitches in unfiltered AS_DC.
Similar effects seen in SPOB_MON and WFS*
AS_Q
1000 Hz HP
“At low frequencies, the model is that there is a broadband noise level in AS_Q which increases monotonically with the AS_DC level. e.g. the stack shakes, the mirrors twist and the light level seen in AS_DC doubles for ~1 sec.
In a whitened time frequency plot this looks like a broad band, 1 sec glitch in AS_Q. It will show up at all frequencies where no other noise source is dominant.
The SPOB_MON veto is also a low frequency veto. The model here is that as the effective sideband recycling gain goes down, the gain in all of the LSC servos goes down. Of these, DARM is the first to go unstable and so we see a burst centered around the lower end of the 'phase bubble' (65-70 Hz). “ (Rana)
AS_Q
100 Hz HP
AS_DC
no filter
REFL_DC
no filter
SPOB_MON
no filter

5. would have been a “safe” veto (tested on hardware injections)
Burst Group Veto Choice for S2 (A. Di Credico, Syracuse, MIT, M. Ito, R. Schofield)
Preliminary selection of candidate vetoes based on preliminary ETG productions (Oct 03):
L1 : LSC-AS_DC (3 s, nofilter)
H1 : LSC-AS_DC(3 s, nofilter)
H2: no candidate
Final choice of veto for S2 burst analysis (Jan 04): no veto used
Channel
Deadtime %
TFCLUSTERS
130Hz-400Hz
Veto Efficiency
400Hz-1000Hz
Veto efficiency
WAVEBURST
(triple coincidence)
L1: LSC-AS_DC
4.42%
13.7%
19.6%
39.5%
would have been a “safe” veto (tested on hardware injections)

6. WaveMon Veto for WaveBurst Candidates (K. Franzen, S. Klimenko)
WaveBurst L1 confidence
WaveBurst H1 confidence
Multiplicity of channels analyzed with WaveMon
Test veto only on triple-coincidence WaveBurst events
Before and after veto plotted vs WaveBurst confidence
Most veto by MICH_CTRL H1 L1
combined
triple H2
WaveBurst H2 confidence
WaveBurst triple coincidence confidence (GC)

7. Glitches in S3 (P. Richerme, MIT)
Scanned the database for AS_Q/aux coincidences
So far only analyzed glitches from glitchMon
(will look also into Zglitch, PTmon, WaveMon...)
Science segments in S3:
L1: 533 segments ( 368 hours)
H1: 508 segments ( 1169 hours)
H2: 718 segments ( 1074 hours)
Several coincidences AS_Q/aux-chan seen
(will not necessarily be true on burst candidates).
The results shown in the next
few slides are all very preliminary:
the search just started...

8. L1:LSC-AS_I 70 Hz high pass, > 4s (same as AS_Q) Efficiency = 35%
Success = 22%
Deadtime=0.5%
L1:LSC-AS_I 70Hz HP
L1:LSC-AS_I 70Hz HP
L1:LSC-AS_I no filter
L1:LSC-AS_I no filter
unfiltered > 4s
Efficiency = 8.5%
Success = 24%
Deadtime=0.08%

9. More Effects at L1 Peaks in lag plot also seen in:
L1:LSC-MICH_CTRL 70Hz HP
channel
HP filter
Dead
time
Efficiency
Success
POB_I
70Hz
0.06%
15%
86%
POB_Q
0.04%
14%
93%
MICH_CTRL
0.11%
17%
65%
PRC_CTRL
0.07%
10%
83%
AS_DC
10Hz
<0.1%
0.13%
70%
Peaks in lag plot also seen in:
REFL_AC REFL_DC REFL_Q
SPOB_MON
L1:LSC-POB_I 70Hz HP
L1:LSC-REFL_Q 70Hz HP
L1:LSC-REFL_DC 10Hz HP
L1:LSC-POB_Q 70Hz HP

10. Glitches at H1 H1:LSC-AS_DC 10Hz HP H1:LSC-AS_I 70Hz HP channel
HP filter
Dead time
Efficiency
Success
AS_I
70Hz
0.02%
26%
62%
10Hz
0.14%
12% 3%
POB_I
0.03%
24%
35%
POB_Q
0.01%
64%
REFL_Q 5%
44%
AS_DC
0.16%
SPOB_MON 8%
34%
REFL_DC
0.05%
11% 7%
H1:LSC-REFL_DC 10Hz HP
H1:LSC-POB_I 70Hz HP

11. Glitches at H2 Also: SPOB_MON, REFL_Q, REFL_I ... H2:LSC-AS_DC 10Hz HP
H2:LSC-AS_I 70Hz HP
channel
HP filter
Dead time
Efficiency
Success
AS_I
70Hz
0.03% 6%
65%
none
0.3% 4%
POB_I
0.13%
10%
51%
POB_Q
0.01%
2.4%
84%
AS_DC
10Hz
0.08% 2%
23%
AS_AC
30Hz
<0.01%
0.5%
63%
REFL_DC
0.6%
68%
H2:LSC-REFL_DC 10Hz HP
H2:LSC-POB_I 70Hz HP
Also:
SPOB_MON, REFL_Q, REFL_I ...

12. Inspiral Candidates (N. Christensen)
Online production of inspiral triggers – used times to scan all PEMs
H1:LSC-AS_Q
GPS : Hz bandpass - LN Dewar glitch?
H0:PEM-LVEA_SEISZ
a few others have a magnetometer in the neighborhood but no smoking gun so far.... IN PROGRESS!

13. Summary S2 glitch investigation: S3 glitch investigation:
Broad rerun over channels/filters ~ complete
Non-linear correlations AS_DC (SPOB_MON, REFL_DC) and broadband bursts
Burst/Inspiral veto choice made (none/L1:LSC-POB_I)
S3 glitch investigation:
Scan of glitchMon triggers in the database - some interesting correlations visible in lag plots and scatter plots.
The search has just started...