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F. Frasconi I.N.F.N. Pisa for the Virgo Collaboration TAUP2007 Sendai, September 11-15, 2007 VIRGO EXPERIMENT VIRGO: a large interferometer for Gravitational.

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Presentation on theme: "F. Frasconi I.N.F.N. Pisa for the Virgo Collaboration TAUP2007 Sendai, September 11-15, 2007 VIRGO EXPERIMENT VIRGO: a large interferometer for Gravitational."— Presentation transcript:

1 F. Frasconi I.N.F.N. Pisa for the Virgo Collaboration TAUP2007 Sendai, September 11-15, 2007 VIRGO EXPERIMENT VIRGO: a large interferometer for Gravitational Wave detection started its first scientific run

2 September 11, 2007F. Frasconi / INFN Pisa2 The Interferometer at EGO site NIKHEF Amsterdam, LAPP Annecy, INFN Firenze-Urbino, INFN Genova, IPN Lyon, INFN Napoli, OCA Nice, LAL Orsay, ESPCI Paris, INFN Perugia, INFN Pisa, INFN Roma1, INFN Roma Tor Vergata

3 September 11, 2007F. Frasconi / INFN Pisa3 VIRGO Optical scheme Laser 20 W Input Mode Cleaner (145 m) Power Recycling 3 km long Fabry-Perot Cavities Output Mode Cleaner (4 cm)

4 September 11, 2007F. Frasconi / INFN Pisa4 Injection System Based on a Nd:YVO4 laser source with 20 W power ( = 1.064  m) Laser Cavity

5 September 11, 2007F. Frasconi / INFN Pisa5 Injection System (cont.) Input mode cleaner cavity about 145 m long based on: - Injection Bench (fall 2005, New Installation ) - End Mirror

6 September 11, 2007F. Frasconi / INFN Pisa6 Detection System (scheme) Suspended bench with optics for beam adjustments and OMC Detection, amplification and demodulation on external bench Laser Beam Suspended Bench External Bench

7 September 11, 2007F. Frasconi / INFN Pisa7 Detection System (cont.) Output Mode-Cleaner External bench Suspended bench

8 September 11, 2007F. Frasconi / INFN Pisa8 Mirror Suspensions The Superattenuator (SA) is the mechanical system adopted to isolate the optical components from seismic activities (local disturbances). It is based on the working principle of a multistage pendulum. Thanks to the isolation performance the system is compliant with future detector upgrades.

9 September 11, 2007F. Frasconi / INFN Pisa9 Main features of SA Thermal Noise Two types of SA: Short Chains & Long Chains; Hybrid system: active control below 4 Hz & passive attenuation starting from 4 Hz; Measured attenuation upper limit: 10 15 at 10 Hz (detection band extended in the low frequency region)

10 September 11, 2007F. Frasconi / INFN Pisa10 Mirror Suspension Control The Inverted Pendulum (IP) is the elastic structure conceived to allow a wide positioning control of the suspension point Hierarchical control of the mirror (3 actuation points): - Inertial Damping on IP (to control tidal strain and drift of any origin ); - Local Control on Marionette (angular mirror displacements reduced down to fraction of  rad); - local damping on Reference Mass (RM).

11 September 11, 2007F. Frasconi / INFN Pisa11 Mirror Suspension Control improvements Several improvements have been done at the control level of the mirror: - global positioning IP control (GPIPC) - better stability for bad weather conditions – “guardian software” for earthquake oscillation high detector stability and high duty cycle

12 September 11, 2007F. Frasconi / INFN Pisa12 Fall 2005 Shutdown The shutdown was suggested by a few major problems found during the commissioning phase: - control problems and alignment drift on PR mirror; - spurious resonances and back-scattered light on suspended IB (no possibility to operate ITF at full power).

13 September 11, 2007F. Frasconi / INFN Pisa13 Fall 2005: detector upgrades (PR) Non-monolithic & Curved mirror induced: - control problems (spurious resonances); - misalignment and jitter noise for vertical translations. Monolithic flat mirror & Parabolic telescope on IB 120 mm R=4100 mm 350 mm Incident beam PR mirror transfer function Old New

14 September 11, 2007F. Frasconi / INFN Pisa14 Fall 2005: detector upgrades (IB) New suspended IB characteristics: - Faraday isolator (fixing back-scattered light) - parabolic telescope - thinner monolithic suspension wires Faraday Isolator

15 September 11, 2007F. Frasconi / INFN Pisa15 Activities before VSR1 Commissioning activity & noise hunting important for:improve controls & automation improve detector reliability & robustness Week-end Science run WSR1 (Sept. 2006)-WSR10 (Mar. 2007) important for:test shift organization data collection Collected data used for: detector characterization data analysis playground prepare joint analysis with LIGO

16 September 11, 2007F. Frasconi / INFN Pisa16 Detector sensitivity evolution

17 September 11, 2007F. Frasconi / INFN Pisa17 The First Virgo Science Run (VSR1) The run started on 18 th May 2007 It will last 4 months (till end of Sept. 2007) In coincidence with the last period of LIGO S5 run

18 September 11, 2007F. Frasconi / INFN Pisa18 Improved sensitivity during VSR1 Sensitivity during VSR1: Sept. 5, 2007 Sensitivity during VSR1: May 18, 2007

19 September 11, 2007F. Frasconi / INFN Pisa19 VSR1 horizon for inspiral sources BNS inspiral range: ~4.0 Mpc Mpc

20 September 11, 2007F. Frasconi / INFN Pisa20 VSR1: detector statistic

21 September 11, 2007F. Frasconi / INFN Pisa21 Data Analysis (DA) LSC-VIRGO agreement on common data taking & DA has been signed Data exchange has been activated since May 2007 (start of VSR1) Organization: - DA groups have been merged (joint review committee created for each working group); - Joint DA committee and run planning committee have been created (discussing the DA activities and run schedule even after VSR1/S5) Final goal: LSC-VIRGO joint analysis - white paper in progress

22 September 11, 2007F. Frasconi / INFN Pisa22 After VSR1 VIRGO is competitive at high frequency with LIGO detectors; VIRGO has the best sensitivity at low frequency (below 40 Hz) even if: the design sensitivity is still far away in the low-medium frequency range. Future activities: - a better understanding of the detector behavior - starting a detector upgrades campaign (VIRGO+ & AdV) to be implemented in parallel with other GW detectors all over the World (eLIGO & advLIGO).

23 September 11, 2007F. Frasconi / INFN Pisa23 VIRGO+ Main goals: - improving the design sensitivity by a factor ~2 - VIRGO+ should be back in Science Mode in 2009 (second half) in coincidence with eLIGO VIRGO+ is meant as a series of detector upgrades: - new IMC payload (new end mirror: better optical quality & larger size) - thermal compensation system - higher laser power (laser amplifier by LZH/GEO) - new mirrors (reduced losses -> higher finesse) - new control electronics

24 September 11, 2007F. Frasconi / INFN Pisa24 Advanced VIRGO (AdV) Goals - improving the VIRGO design sensitivity by a factor ~10 - back in data taking around 2013-2014 Main scheduled changes: - higher power laser (optical readout noise) - heavier mirrors (optical readout noise) - better coatings (thermal noise) - signal recycling (shape the sensitivity curve) - beam waist position (thermal noise) AdV Conceptual Design document in preparation The exact AdV upgrades still under discussion

25 September 11, 2007F. Frasconi / INFN Pisa25 Conclusions VIRGO still in Science Mode - VSR1 started in May: data taking 4 months long - very good detector stability (thanks to control improvements) - good duty cycle in science mode (~ 82%) - 18 locking periods longer than 40 hours - BNS inspiral range at 4.0 Mpc level VIRGO+ upgrades - improving the design sensitivity of a factor ~2: preparation in advanced status - commissioning period of the upgrades -> back in science mode within the second half of 2009 (in coincidence with eLIGO) AdV upgrades - working groups & coordinators: defined - improving the design sensitivity of a factor ~10: conceptual design document in progress to be submitted to the Funding Institutions by the end of the year


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