Virgo Commissioning: Status and Plans October 24th 2005 Matteo Barsuglia, LAL/CNRS

Status at the Prague meeting Interferometer in the recycled (full) configuration with 0.7 W (reduced power) Last data taking: C5 (dec 2004, 5 days) Main commissioning activities: interferometer control set-up and tuning Linear alignment Hierarchical control Automation Problems of interferometer bistabilities

Reduced power: motivations Laser Frequency (Hz) fringes Short term solution: put attenuator between the IMC and the ITF  Power attenuated (8 W0.8 W)

Final solution: Faraday isolator and new bench Brewster dielectric polarizers Rotator Installation of the new bench on going

C5 sensitivity (Dec 2004) Recycled interferometer 0.8 W input power Typical locking time: 1 hour

The interferometer bistabilities Present continuously since january 2005 Interferometer internal power (a.u.) Continuous interferometer unlocks No science operations No standard commissioning work Problem solved in july 2005 with: 1. Better photodiode centering 2. Special alignment of the injection bench 3. Special tuning of a demodulation phase of a signal involved in the interfererometer control The effects 2,3 can be explained with a presence of spurious beams, stray light, or beam clipping at the injection bench level Actions taken for the new injection bench 1 sec

Last months summary Problem of bistabilities solved Automatic alignment completed Hierarchical control completed First phase of detector automation completed Progress in noise hunting Two data taking (C6 14 days, C7 5 days)

Linear(automatic) alignment/1

Linear alignment/2 Fluctuations Drifts Internal power Dark fringe power (W) Fluctuations 100 sec Drifts 1 hour

Linear alignment/3 Linear alignment completed: 10 degrees of freedom controlled with the full bandwitdh

Linear alignment/4 C6 (august 2005) C5 (december 2005) 1 day

Interferometer internal power Hierarchical control Actuators noise f < 10 mHz Motivation: re-allocate the control force on upper stages to reduce actuator noise Interferometer internal power Force on marionetta Force on mirror 10 mHz < f < 10 Hz f > 10 Hz

Detector automation Hundreds of operations during alignment/locking of ITF  One single script to bring the detector in science mode in ~5 minutes Automation status Interferometer internal power Marionette Low noise coil drivers AA ON OMC lock Other noise reductions and calibration Lock to dark fringe with variable finesse

C6 and C7 summary C6 (july 29th – aug 12th) C7 (Sept 14th sept 19th) Partial automatic alignment Science mode duty cycle 86% Longest lock 40 hours Best inspiral range 0.54 Mpc Automatic science mode recovering ~5 minutes C7 (Sept 14th sept 19th) Full automatic alignment and full hierarchical control Science mode duty cycle 65% Longest lock 14 hours Best inspiral range 1.65 Mpc Automatic science mode recovering ~5 minutes

C6 and C7 Sensitivities feedback noises Shot noise

Next steps Change injection bench and increase the power (x10) Commissisoning of “high power” interferometer Restart the injection system Restart the interferometer  January 2006 Check problems with high power (try to reach ~500 W on BS) Complete ITF control set-up and tuning  February 2006 Start/Continue noise hunting Priority first on middle-high frequency range (> 50 Hz) Acoustic, diffused light, actuators noise…

Summary 90% of controls reliably working Progress: Automatic alignment completed Full hierarchical control completed First phase of automation completed C6 and C7 data takings 1.65 Mpc detector robust (C6: 86%, C7: 65%) Detector left locked during nights, first trials 90% of controls reliably working Science mode with a single script Assembly of the new injection bench on going Interferometer restart in January Commissioning of high power interferometer Noise hunting