VIRGO Control System Upgrade: Multi-DSP Board Alberto Gennai INFN Pisa LIGO-G070351-00-Z.
COMMISSIONING PROGRESS G.LOSURDO – INFN Firenze for the Virgo Collaboration.
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Transcript of 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
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
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
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 7/25
@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
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 (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
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 timeA frequency dependent does not help
Solution:automatic Beta tuningAlp 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 MHz8.35 MHz
ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 14/25
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
ILIAS WG1 - CERN, Mar. 30th, 2007 G.Losurdo – INFN Firenze 15/25
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
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 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
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