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Virgo Commissioning: Status and Plans

October 24th 2005Matteo Barsuglia, LAL/CNRS

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• 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

Status at the Prague meeting

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Laser Frequency (Hz)

Short term solution: put attenuator between the IMC and the ITF Power attenuated (8 W0.8 W)

fringes

Reduced power: motivations

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Brewster dielectric polarizers

Rotator

Installation of the new bench on going

Final solution: Faraday isolator and new bench

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C5 sensitivity (Dec 2004)

Recycled interferometer 0.8 W input power

Typical locking time: 1 hour

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The interferometer bistabilities • Present continuously since january 2005

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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 bench3. 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

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• 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)

Last months summary

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Linear(automatic) alignment/1

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Linear alignment/2 Internal power Dark fringe power (W)

100 sec

1 hour

Fluctuations

Drifts

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Linear alignment/3

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

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Linear alignment/4

C6 (august 2005)

C5 (december 2005)

1 day

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Hierarchical control f < 10 mHz

10 mHz < f < 10 Hz

f > 10 Hz

Motivation: re-allocate the control force on upper stages to reduce actuator noise

Force on marionetta

Force on mirror

Actuators noise

Interferometer internal power

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Detector automation • Hundreds of operations during alignment/locking of ITF

One single script to bring the detector in science mode in ~5 minutes

Lock to dark fringe with variable finesse

AA ONOMC lock

MarionetteLow noise coil drivers

Other noise reductions and calibration

Interferometer internal powerAutomation status

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• 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

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C6 and C7 Sensitivities

ILIAS WG1 – Perugia, September 19, 2005 G.Losurdo – INFN Firenze-Urbino 3

Shot noise

feedback noises

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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…

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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