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Detector Characterisation (Glitches)
narnaud - 12:05 Thursday 28 November 2024 (65646) Print this report
Rare but strong glitches: associated channels found by UPV

Since yesterday evening there are rare but strong (SNR > 100, up to 1000 or higher) glitches. And this time UPV finds some vetoes. I've run it on the past 24 hours and the results are at https://scientists.virgo-gw.eu/DataAnalysis/UPV/2024/20241128/last_day_1416736178-1416822578/V1:Hrec_hoft_16384Hz/perf/vp.html. The best witness channels are

Vetoes

Number of vetoes: 382
Dead time: Integrated time when the veto is active. We note d the fraction of the total livetime (69028 s) when the veto is active.
Efficiency (ε): This is the fraction of V1:Hrec_hoft_16384Hz triggers which are vetoed.
ε/d: This factor is larger than 1 when the veto rejects more triggers than a random veto.
V1:Hrec_hoft_16384Hz: 19377 clusters
V0 → V1:SWEB_B8_DC_0, vetoed clusters: 79 (0.408 %)
V1 → V1:SWEB_B8_DC_D_0, vetoed clusters: 78 (0.403 %)
V2 → V1:PSTAB_PDa_DC_0, vetoed clusters: 49 (0.253 %)
V3 → V1:SPRB_B4_DC_0, vetoed clusters: 42 (0.217 %)
V4 → V1:ASC_B4_QD2_Sum_0, vetoed clusters: 38 (0.196 %)
V5 → V1:PSL_PMC_QD_FF_V_0, vetoed clusters: 38 (0.196 %)
V6 → V1:PSL_PMC_QD_NF_V_0, vetoed clusters: 35 (0.181 %)
V7 → V1:SIB2_RFC_PD2_Audio_0, vetoed clusters: 34 (0.175 %)
V8 → V1:SIB2_B2_DC_0, vetoed clusters: 34 (0.175 %)
V9 → V1:INJ_IBJM_DC_H_e_0, vetoed clusters: 32 (0.165 %)
V1-Hrec_hoft_16384Hz-vetoall_freqtime.png

The effect of these vetoes can be seen by following a link "click here to expand/hide" and comparing the time-frequency trigger distribution before and after the veto. For instance before / after for the V1:SPRB_B4_DC-based veto.

Comments to this report:
melo, spinicelli - 17:35 Thursday 28 November 2024 (65649) Print this report

The glitches have been spotted also in the PMC channels as we can see in the attached figure. 

In the past we have seen that a decrease of the PMC power, related to the temperature increase of the Neovan head can cause an anomalous behaviour of the PSTAB and ITF channels (eLog 62974). As we are facing a similar problem at the moment (Fig. 2), we are going to further investigate this issue as soon as possible. 

 

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narnaud - 23:21 Wednesday 04 December 2024 (65721) Print this report
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