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Instrumental and environmental noise in GEO600

Instrumental and environmental noise in GEO600. Picture of GEO in stormy weather?? Or pics of tractors with trees?. Joshua Smith for the GEO 600 team. North building. Overview. A selection of recent detector characterization work. Environmental: Seismic Dust Magnetic fields / Mains.

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Instrumental and environmental noise in GEO600

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  1. Joshua Smith, Elba, Italy 31.05.06

  2. Instrumental and environmental noise in GEO600 Picture of GEO in stormy weather?? Or pics of tractors with trees? Joshua Smith for the GEO600 team North building Elba, Italy 31.05.06

  3. Overview A selection of recent detector characterization work • Environmental: • Seismic • Dust • Magnetic fields / Mains • Instrumental: • Noise Projections • Tracking couplings • Noise subtraction • Noise vetoes Joshua Smith, Elba, Italy 31.05.06

  4. Seismic / up-conversion H @ 240Hz H @ 290Hz Amplitude (max) H @ 340Hz Seis @ 49Hz Joshua Smith, Elba, Italy 31.05.06 0 Time [h] 3.5

  5. Dust Joshua Smith, Elba, Italy 31.05.06

  6. Power glitches Input port power Detector output Joshua Smith, Elba, Italy 31.05.06

  7. Back-coupling? Strain back-coupling doesn’t explain instrumental channel coincidence Dark port DC Power Strain coupling to DC power Joshua Smith, Elba, Italy 31.05.06

  8. Power glitches vs. dust Particle count Dark port DC power glitch count Dark port DC power glitch count Dark port DC power glitch count Input port DC power glitch count Joshua Smith, Elba, Italy 31.05.06 0 Time [m] 180

  9. Particle waves filtered 14020 455 (Particles/cu.ft)/1000 30.2 A a Joshua Smith, Elba, Italy 31.05.06

  10. Dust made loudest glitches Det. output BLRMS @~ 170Hz Time [h] Time [h] Before filter After filter Joshua Smith, Elba, Italy 31.05.06

  11. Magnetic fields / Mains Joshua Smith, Elba, Italy 31.05.06

  12. Magnetic field glitches H glitches B glitches Linear coupling, coherence Joshua Smith, Elba, Italy 31.05.06

  13. Magnetic field “projection” • B-field nearly limiting noise around 100Hz? • Coupling not yet understood • Checks: magnetometer measures B-field, IFO back-coupling ruled out Joshua Smith, Elba, Italy 31.05.06

  14. Hourly mains glitches 24s • Hourly series start: • 24 secs after GPS hour • 10 secs after UTC hour Joshua Smith, Elba, Italy 31.05.06

  15. Mag./mains coinc. with H Magnetometer central building ~ 50coinc./8hrs Mains monitor central building ~ 30coinc./8hrs Time-freq glitch maps Frequency [Hz] Frequency [Hz] 0 8 0 8 Time [h] Time [h] 50 50 Time-shifted coincidence 0 0 Joshua Smith, Elba, Italy 31.05.06 1 1 -1 -1 Time shift [s] Time shift [s]

  16. Noise Projections Joshua Smith, Elba, Italy 31.05.06

  17. Noise Budget Alignment actuation Shot, dark, osc. phase Scattering, up-conversion, ? Joshua Smith, Elba, Italy 31.05.06

  18. Tracking noise transfer func’s Amp ratio ~ 1 phase diff ~ 0 Tracked: Signal Recycl. FB Osc. Phase Laser intensity Frequency Joshua Smith, Elba, Italy 31.05.06

  19. Transfer func’s: long-term (10d) Ratio/Diffs drifts Histogram of drifts 10 days, most projections: +/- 10% mag +/- 10 degs phase So, long-term stable Joshua Smith, Elba, Italy 31.05.06

  20. Noise transfer func’s: short-term +/- 20% mag. variations on second timescales! Joshua Smith, Elba, Italy 31.05.06

  21. Noise Subtraction Joshua Smith, Elba, Italy 31.05.06

  22. Detector output and noise Detector output Noise projection Noise budget Noise chans. Record subset Joshua Smith, Elba, Italy 31.05.06 Improved H

  23. Noise subtraction requirements Subtraction factor depends on amplitude ratio and phase difference of filter used and real transfer function response. Joshua Smith, Elba, Italy 31.05.06

  24. Noise subtraction results Ratio H/(H-Projs) Time domain subtraction, simple IIR filters fit to measured TF response. But, no reduction of up-conversion Joshua Smith, Elba, Italy 31.05.06

  25. Technical noise veto Joshua Smith, Elba, Italy 31.05.06

  26. Noise veto: eg. injection H Michelson oscillator phase noise Joshua Smith, Elba, Italy 31.05.06

  27. Noise veto performance Estimated veto efficiency vs. rejection probability for the chosen thresholds. “Robust vetoes for gravitational-wave burst triggers using known instrumental couplings” P. Ajith, M. Hewitson, J. R. Smith, K. A. Strain, submitted to CQG, http://arxiv.org/abs/gr-qc/0605079 Joshua Smith, Elba, Italy 31.05.06

  28. The end 'falco tinnunculus', better know as 'Turmfalke' Joshua Smith, Elba, Italy 31.05.06

  29. Noise subtraction II Used simple IIR filters - good match to simple transfer function Joshua Smith, Elba, Italy 31.05.06

  30. Statistical dust veto? MID VIS veto TF map and timeshifted results Joshua Smith, Elba, Italy 31.05.06

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