Noise meeting on Thursday Oct 18 at 9:30 am

 

Agenda

1. VSR1 Piezo Issues: Beam jitter and Mystery Noises Julien Marque 15'

2. Dark fringe slow non-stationarities Gabriele Vajente 30'

3. Evolution of horizon during VSR1 Edwige Tournefier 15'
   

4. VSR1 environmental noise budget Irene Fiori 30'

5. Harmonics corrector Federico Paoletti 10'
   
6. Magnetic noise Dominique Huet 15'
7. Identification of spectral lines in VSR1 pulsar searches 15' Cristiano Palomba 15 '
   

8. Low frequency seismic noise: locking and sensitivity issues Paolo Ruggi 30'

9. Virgo DataBase ed  Quality flags definitions Leone Bosi 10'
   
10. Some considerations about far away strong earthquakes Angela Di Virgilio 15'
    

11. Veto study and transient analysis on segments of VSR1 Marina Del Prete 15 '

Presentation directory

/opt/w3/DataAnalysis/Noise/doc/Noise_meetings/2007/20071018/

Presentation web page

http://wwwcascina.virgo.infn.it/DataAnalysis/Noise/doc/Noise_meetings/2007/20071018/

Connection

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Present

Dominique Huet, Paolo Ruggi, Gabriele Vajente, Angela Di Virgilio, Stefano Braccini, Marina Del Prete, Elena Cuoco, Irene Fiori, Edwige Tournefier, Leone Bosi, Isidoro Ferrante, Michele Punturo, Vincenzo Dattilo, Shourov Chatterji, Adalberto Giazotto, Carlo Bradaschia, Benoit Mours, on phone: Cristiano Palomba, Ettore Majorana, Didier Verkindt.

Julien: use IB_zCorr as veto before the problem of RFC piezos is cured. Many improvements: stationarity, lines. Amount of glitches decreases drastically. See also conclusions. Mods 19 Sep for mistery noise. Mods for BMS on July 18. About 6 kHz bump, some coherence with  magnetometers.  Bench motion could introduce also jitter in the beam entering the interferometer.

Gabriele: analysis of BRMS: regression with auxiliary channels. Quite predictive. 1-10 kHz depends on dark fringe power, suspended benches corrections RMS, temperature inside labs and towers. 100-1000 Hz: IB RMS, mirror vertical position, end mirror angular RMS, dark fringe power before OMC, alpha and beta. Below 100 Hz: seismic conditions, poyload position, arm cavities transmission, alpha and beta, ISYS and IMC angular corrections.

Edwige: RFC filters, beam centering, BS filters, sideband balancing, magnetic lines, early July: filtering of coil drivers, mystery noise, highly non stationary. Common mode noise (PRCL+freq) is more coupled with etalon effect. Brewster noise: diffused light or brewster window phase noise? Eddy currents: is it an upper limit or a true level? Still to fix input beam jitter noise. Should introduce in noise budget input beam jitter.

Irene: tools: environmental coherence cataloghe, web line monitor. Miracle of ENEL cutoff. End building ENEL silence reproduced, not in the main building. DAQ air conditioning not turned off, might have an effect on brewster. 5-60 Hz:coherence with microphones and episensors in Laser lab. See other slides for a comprehensive discussion and references to logbook. Sensitivity of laserlab: study which racks contribute. Note bench resonances, why is the frequency so low. Fans to be eliminated. What about water cooling?

Federico: Harmonic corrector. Introduction of new UPS introduces noise on the line. Introduction of Harmonic corrector introduces bump at 8 kHz.

Dominique: description of magnetic hunt, with entries. LC illuminator coherence with darkfringe. Fan of LC illuminator. Several lines below 100 Hz removed. Measurement of B in the oven at 10 nT/sqrt Hz can be seen in the dark fringe. Lateral magnet coupling. Careful that the lines extend further in the spectrum. The dates of switching off fans are reported in the logbook. What about magnetic shield the oven?

Cristiano: report on line analysis from continuous source data analysis. Resolution better than 10^-3 Hz.

Paolo: 200-300 Hz spectrum spoiled by bad weather. Power in cavities less stable. If improve tz IB power inside the interferometer is much more stabilized. Not only peaks but floor rises. Sensitivity at 100-500 Hz spoiled by misalignment. Measure "input noise" to the suspension looking at the top stage lvdts (bad weather: 10 times worse).  In dark firnge, factor three. Increase in IB  above 3 Hz.  Pseudo seismic noise injection:  something done in tx, nothing in ty. Diff end tx perturbation. IMC studies: observed power instability reproduced. Tests to be continued.

Leone: description of data quality database. Your favorite additional segment definitions to be or'ed or and'ed are welcome.

Marina: some loud events can be vetoed looking at magnetometers, accelerometers, and power line. Investigation on other data segments (presence of lightnings, good final data) will be performed.