commissioning progress g.losurdo – infn firenze for the virgo collaboration

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 #

date duty cycle

1 Sep 8-11 90

2 Sep 22-25 65

3 Oct 6-9 cancelled

4 Oct 13-16 cancelled

5 Nov 10-13 65

6 Dec 1-4 80

7 Jan 12-15 76

8 Feb 9-12 94

9 Feb 17-19 100

10 Mar 9-12 70

3 more Weekly Science Runs performed4 months science run due to start on May 18th


Virgo vs LSC


Detector plans

2006 2007

RunCommissioning

FULL LSC-Virgo DATA EXCHANGEwill start on May 18th

FULL LSC-Virgo DATA EXCHANGEwill 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 2007.

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 2007.

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


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.


@Copyright

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


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


MICH Noise Injection (alpha=0)

MICH Noise Injection (const alpha)

MICH Noise Injection (6th order filter)

Frequency dependent Alpha - MICH

A frequency dependent has been introduced, improving the result: a factor ~20 of cancellation everywhere

Effect on sensitivity


Beta - PRCL

Problem with the Beta subtraction:the coupling PRCL dark fringe varies considerably with timeA frequency dependent does not help

Solution:automatic Beta tuningAlp macro done and tested


New MICH filter

Modified roll-off:MICH control noise reduced

around 50 Hz

before after


angular control


WSR10 alignment layout

6.26 MHz8.35 MHz


2nd modulation frequency

Virgo mod. (6.26 MHz)

2nd mod. (8.35 MHz)

2nd 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)

2nd mod. on the same EOM =>line forest on EOM => perturbed locking signals

Solution: added 2nd EOM =>Much less problems but weaker modulation index to avoid perturbations. To be investigated


corr

10 Hz

beforeafter

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

Zcorr (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


Automatic control noise budget

Automatic procedure to calculate the noise budget for longitudinal and angular control (a few minutes of noise injections)


Suspension controls


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


Detection bench local contol

The big haircut: 28 Hz line with “hair” cancelled with better roll-off

on detection bench local control


pollutions


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)


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)


External bench reshuffling

General re-organisation

– simplified setup– 2” optics – dump the photodiode

reflection– dust cover


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 dipolegluing 4 magnets with opposite polarity on the front face

The original sin: the 4 magnetshave been glued with the samepolarity on NI/WI mirrors


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


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


Hardware Limit

Sensitivity today


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

commissioning progress g.losurdo – infn firenze for the virgo collaboration

Documents

losurdo infn firenze

f b2 b2

prcl slide

ilias wg1 cern

prcl mich mich

virgo collaboration

mix of b2

virgo vs lsc slide