Reports until 09:38, Friday 19 April 2019
H1 SUS
jeffrey.bartlett@LIGO.ORG - posted 09:38, Friday 19 April 2019 - last comment - 09:43, Friday 19 April 2019(48612)
Damp ETM-X Violin Mode 13 
   ETM-X violin mode13 had been ringing up all evening and was up approaching 4.7 this morning. Took advantage of LLO being down to suppress this mode.

   16:20 (09:20) Dropped out of Observing to Commissioning 
   Set VIOLIN_DAMPING to DAMPING_ON_SIMPLE
   Applied +30 gain to H1SUS-ETMX_L2_DAMP_MODE13
   Confirmed the mode had turned down
   Set VIOLIN_DAMPING back to DAMPING_ON_DC
   16:25 (09:25) Back into Observing
Comments related to this report
rahul.kumar@LIGO.ORG - 09:43, Friday 19 April 2019 (48614)
Link

I have attached 2 plots which shows the ndscope of the monitor levels and power spectrum (for 2nd harmonics). Mode 13 (1010.30 Hz) was rising for several hours (after Guardian decided to switch off damping), following which Jeff applied damping_on_simple, the excitation level fell off sharply - in the power spectrum plot, one can see the peak droping from 10^-15 m/sqrtHz  to 10^-19m/sqrtHz level.

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