Virgo Update B Mours LIGOG 060105 00 Z

Virgo Update B. Mours LIGO-G 060105 -00 -Z March , 2006 Virgo Status – LSC meeting

Fall 2005 shutdown l New injection bench u Full redesign u Faraday isolator » Go to the nominal power u New Input Mode cleaner alignment scheme l New Recycling mirror u Go to a monolithic mirror u Change the input telescope » Use parabolic mirrors on the “injection bench” l Expect 500 W on the beam splitter u x 20 compared to C 7 l Back to vacuum end of November March , 2006 Virgo Status – LSC meeting u Adjusting the reflectivity (92% 95%) increase of the recycling factor

Virgo re-commissioning l December: u Restart the local controls u Realign the injection system l January u Relock the input mode cleaner (5 Jan 06) u Realign the input telescope u Measure TF for the new recycling mirror. l February u Relock the long cavities » 88% beam matching up to now u Relock the reference cavity l March u Relock the full Virgo l Slow down by the usual problems: u Alignment, broke a translation stage, pico-motors, faulty electronic, , … March , 2006 Virgo Status – LSC meeting

Virgo status now l Virgo locking scheme: u Variable finesse technique: » » » l B 8 p Lock on the half fringe Used transmitted beam to lock the cavities Start the frequency stabilization servo Align PR mirror Fringe offset adiabatically reduced Use different error signals B 2_3 f_ACp l 1 Now (Saturday) u ITF relock: l 0 » PR aligned » 5% of the dark fringe Recycling Misaligned ITF on Grey Fringe L 1 L 2 l 2 B 1 p_DC u Power in the arms 2 X before shutdown » still a factor 10 to go March , 2006 STEP 1 Virgo Status – LSC meeting B 7 p

Data Analysis: some examples l Using C 6/C 7 data (Aug-September 05) u C 7; inspiral horizon = 1. 5 Mpc (optimal orientation) l Goal u Develop the data analysis u Understand better the detector noises and non stationarities March , 2006 Virgo Status – LSC meeting

Learn how to deal with relock l Well known problem of excitation after a relock u Trigger rate of some burst algorithms before/after cutting violin/internal modes resonances: (167 -333 -3884 -3916 Hz) No Cut March , 2006 With adaptive notches Virgo Status – LSC meeting

Burst of burst events l “Burst of Bursts”: u Observe long events (after clustering) u Correlated with mirror angle » The residual angular motion change the coupling with the frequency noise u Non stationarities in the whitened channel Minimal Coupling March , 2006 Virgo Status – LSC meeting BOBs

Example of Bursts distribution l Mean Filter algorithm l Veto on misalignment u 30% dead time l Get closer to the MC distribution March , 2006 Virgo Status – LSC meeting

Other problems found with bursts l Bursts in dark fringe and detection bench accelerometer l Origin: u Centering of the quadrant every 6 second March , 2006 Virgo Status – LSC meeting

C 6 -C 7 data quality l Not science quality data u But good to learn et get ready l C 6 -C 7 period: u Fast commissioning progress u Only a few months of stable operation March , 2006 Virgo Status – LSC meeting

Next Virgo steps l 2006 u Interferometer restart: Now u Recycled ITF commissioning: 3 Months » Start data taking during weed-ends and nights u Noise hunting: 4 Months ? u Start a Science Run (NS-NS horizon around 15/2. 5 Mpc? ) u Data taking > 30% of the time ? l 2007 u A possible shutdown to fix problems u Commissioning and noise hunting u Nominal sensitivity u Data taking > 50% of the time March , 2006 Virgo Status – LSC meeting

Virgo+ l Independent changes u Same optical layout u Monolithic suspension u 50 W laser u “Short” shutdown l “Low” cost upgrades u 1 -2 M€ l Installation target: early 2008 Inspiral Range (Mpc): (averaged orientation ) Virgo+ (a) Virgo+ (b) NSNS 12 46 22 BHBH 58 234 116 March , 2006 Virgo Status – LSC meeting