COMMISSIONING PROGRESS G.LOSURDO – INFN Firenze for the Virgo Collaboration

ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 2/25 Progress since last meeting WSR #dateduty cycle 1Sep Sep Oct 6-9cancelled 4Oct 13-16cancelled 5Nov Dec Jan Feb Feb Mar more Weekly Science Runs performed 4 months science run due to start on May 18th

ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 3/25 Virgo vs LSC

ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 4/25 Detector plans Run Commissioning FULL LSC-Virgo DATA EXCHANGE will start on May 18th FULL LSC-Virgo DATA EXCHANGE will start on May 18th LSC Council resolution - March 20, 2007 The LSC Council endorses the implementation of the data sharing provisions of our agreement with Virgo, starting on 18 May We look with favor on exchanges of data before then, for technical purposes. The Council asks the joint Run Planning Committee to meet intensively in the coming weeks, and to present at the May Collaboration meeting a set of options for joint running of the Virgo, GEO, and LIGO interferometers over the next few years. LSC Council resolution - March 20, 2007 The LSC Council endorses the implementation of the data sharing provisions of our agreement with Virgo, starting on 18 May We look with favor on exchanges of data before then, for technical purposes. The Council asks the joint Run Planning Committee to meet intensively in the coming weeks, and to present at the May Collaboration meeting a set of options for joint running of the Virgo, GEO, and LIGO interferometers over the next few years. 4 months

COMMISSIONING ISSUES: longitudinal control

ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 6/25 B2_ACp  B2_3f has bad SNR: control noise limiting (or close to limit) the sensitivity below 200 Hz WSR6 Switch to B2 to reduce the noise Longitudinal control noise - PRCL Problem: the switch to B2 is stable if the “good” operation point is found. This is not easy and not reproducible.

ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze B2_3f B2 B2_mix - PRCL  Combine stability at low frequency and good noise performance above 10 Hz  B2_3f replaced by a mix of B2_3f (low passed) and B2 (high passed)  Good stability achieved. Noise performance comparable with B2 only

ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 8/25 PRCL MICH MICH and PRCL corrections sent to the end mirrors to subtract the noise reintroduced by these loops into the dark fringe Linear Coupling Approximation: MICH  coupling coeff is called ALPHA PRCL  coupling coeff is called BETA Alpha and Beta – MICH and PRCL

ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 9/25 MICH Noise Injection (alpha=0) MICH Noise Injection (const alpha) MICH Noise Injection (6 th order filter) Frequency dependent Alpha - MICH A frequency dependent  has been introduced, improving the result: a factor ~20 of cancellation everywhere Effect on sensitivity

ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 10/25 Beta - PRCL Problem with the Beta subtraction: the coupling PRCL  dark fringe varies considerably with time A frequency dependent  does not help Solution: automatic Beta tuning Alp macro done and tested

ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 11/25 New MICH filter Modified roll-off: MICH control noise reduced around 50 Hz before after

COMMISSIONING ISSUES: angular control

ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 13/25 WSR10 alignment layout 6.26 MHz 8.35 MHz

ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 14/25 2 nd modulation frequency Virgo mod. (6.26 MHz) 2 nd mod. (8.35 MHz) 2 nd modulation frequency needed for having absolute (demodulated) reference for common end mirror alignment Previously aligned with ITF reflected light (Q21) DC signal IMC mod. (22.4 MHz) 2 nd mod. on the same EOM =>line forest on EOM => perturbed locking signals Solution: added 2 nd EOM => Much less problems but weaker modulation index to avoid perturbations. To be investigated

ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 15/25 corr 10 Hz before after End mirror beam centering  Shake end mirror tx/ty  If mirror is miscentered: cavity length oscillates  Lines visible in the locking correction signal  Tune input mirror alignment  null the line in Z corr (repeatable to 0.5 urad)  New input mirror alignment loops (Alp)  very slow (some mHz)  mirror center as reference  before: odd combinations of end quadrant DC’s

ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 16/25 Automatic control noise budget Automatic procedure to calculate the noise budget for longitudinal and angular control (a few minutes of noise injections)

COMMISSIONING ISSUES: Suspension controls

ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 18/25 Sensitivity to environmental conditions considerably decreased –larger gain in automatic alignment loops –better cut-off in damping of inverted pendulum respect to ground –damping of inverted pendulum respect to ground switched OFF on 4 suspensions (GIPC) –Reallocation of DARM correction split over both marionettes WSR8 Darker and more stable dark fringe Stability evolution Improved stability of BNS horizon (with similar environmental conditions) see talk by Ettore

ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 19/25 Detection bench local contol The big haircut: 28 Hz line with “hair” cancelled with better roll-off on detection bench local control

COMMISSIONING ISSUES: pollutions

ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 21/25 Laser Brewsters End benches Detection bench Injection bench Stray light See talk by Julien Environmental noise acting on in air components + Scattered light from in air components = Phase noise in the interferometer (with the typical environmental-like noise structures)

ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 22/25 Acoustic noise reduction Acoustic isolation box –installed around laser and injection tables –to be installed around detection table (April) –ordered also for terminal benches (to be installed when possible)

ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 23/25 External bench reshuffling General re-organisation –simplified setup –2” optics –dump the photodiode reflection –dust cover

ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 24/25 Electromagnetic noise Electromagnetic noise hunting –coherence with electromagnetic sensors observed –sources of magnetic field near the mirror tracked –noisy power supplies identified and removed dark fringe spectrum Possible solution: null the dipole gluing 4 magnets with opposite polarity on the front face The original sin: the 4 magnets have been glued with the same polarity on NI/WI mirrors

ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 25/25 Effects of turbo pumps  Noise reduction after switch off of the turbo pumps and some vacuum racks in the central area  Noise reduction observed also on the accelerometer on the brewster

ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 26/25 New SSFS board  More professional electronics  More gain in the 1-5 kHz range  Low freq gain to be increased soon old SSFS board sensitivity improvement

ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 27/25 Hardware Limit Sensitivity today

ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 28/25 Short term plans  Noise hunting –replacement of Brewster window with larger one –installation of more acoustic isolation –actuator noise reduction –control noise investigations  Run preparation  Virgo Science Run 1 to start May the 18th  Noise hunting –replacement of Brewster window with larger one –installation of more acoustic isolation –actuator noise reduction –control noise investigations  Run preparation  Virgo Science Run 1 to start May the 18th