Joshua Smith, Elba, Italy Elba, Italy Joshua Smith for the GEO 600 team Picture of GEO in stormy weather?? Or pics of tractors with trees? Instrumental and environmental noise in GEO600 North building Joshua Smith, Elba, Italy Overview Environmental: oSeismic oDust oMagnetic fields / Mains Instrumental: oNoise Projections oTracking couplings oNoise subtraction oNoise vetoes A selection of recent detector characterization work Joshua Smith, Elba, Italy Seismic / up-conversion 240Hz 290Hz 340Hz 49Hz 0 Time [h] 3.5 Amplitude (max) Joshua Smith, Elba, Italy Dust Power glitches Detector output Input port power Joshua Smith, Elba, Italy Back-coupling? Strain coupling to DC power Dark port DC Power Strain back-coupling doesnt explain instrumental channel coincidence Joshua Smith, Elba, Italy Power glitches vs. dust Dark port DC power glitch count Particle count Dark port DC power glitch count Input port DC power glitch count 0 Time [m] 180 Joshua Smith, Elba, Italy Particle waves filtered 140 5 3 0.2 (Particles/cu.ft)/1000 AaAa Joshua Smith, Elba, Italy Dust made loudest glitches Before filterAfter filter Time [h] Det. output 170Hz Joshua Smith, Elba, Italy Magnetic fields / Mains Joshua Smith, Elba, Italy Magnetic field glitches B glitches H glitches Linear coupling, coherence Joshua Smith, Elba, Italy Magnetic field projection B-field nearly limiting noise around 100Hz? oCoupling not yet understood oChecks: magnetometer measures B-field, IFO back-coupling ruled out Joshua Smith, Elba, Italy Hourly mains glitches Hourly series start: o24 secs after GPS hour o10 secs after UTC hour 24s Joshua Smith, Elba, Italy Mag./mains coinc. with H Frequency [Hz] Magnetometer central building ~ 50coinc./8hrs Time-freq glitch maps Time-shifted coincidence Mains monitor central building ~ 30coinc./8hrs Time [h] Time shift [s] 1 1 Frequency [Hz] Joshua Smith, Elba, Italy Noise Projections Joshua Smith, Elba, Italy Noise Budget Alignment actuation Scattering, up-conversion, ? Shot, dark, osc. phase Joshua Smith, Elba, Italy Tracking noise transfer funcs Tracked: Signal Recycl. FB Osc. Phase Laser intensity Frequency Amp ratio ~ 1 phase diff ~ 0 Joshua Smith, Elba, Italy Transfer funcs: long-term (10d) 10 days, most projections: +/- 10% mag +/- 10 degs phase So, long-term stable Ratio/Diffs drifts Histogram of drifts Joshua Smith, Elba, Italy Noise transfer funcs: short-term +/- 20% mag. variations on second timescales! Joshua Smith, Elba, Italy Noise Subtraction Joshua Smith, Elba, Italy Detector output and noise Detector output Noise chans. Record subset Noise projection Noise budget Improved H Joshua Smith, Elba, Italy Noise subtraction requirements Subtraction factor depends on amplitude ratio and phase difference of filter used and real transfer function response. Joshua Smith, Elba, Italy Noise subtraction results Time domain subtraction, simple IIR filters fit to measured TF response. Ratio H/(H-Projs) But, no reduction of up-conversion Joshua Smith, Elba, Italy Technical noise veto Joshua Smith, Elba, Italy Noise veto: eg. injection H Michelson oscillator phase noise Joshua Smith, Elba, Italy Noise veto performance Robust vetoes for gravitational-wave burst triggers using known instrumental couplings P. Ajith, M. Hewitson, J. R. Smith, K. A. Strain, submitted to CQG,Estimated veto efficiency vs. rejection probability for the chosen thresholds. Joshua Smith, Elba, Italy The end 'falco tinnunculus', better know as 'Turmfalke' Joshua Smith, Elba, Italy Noise subtraction II Used simple IIR filters - good match to simple transfer function Joshua Smith, Elba, Italy Statistical dust veto? MID VIS veto TF map and timeshifted results