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

1. Virgo Commissioning: Status and PlansOctober 24th 2005Matteo Barsuglia, LAL/CNRS

2. 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

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

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

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

6. 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

7. 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)

8. Linear(automatic) alignment/1

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

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

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

12. 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

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

14. C6 (july 29th – aug 12th) 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 summary

15. C6 and C7 Sensitivities feedback noises Shot noise

16. 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…

17. Summary • 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