Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut) Institut für Atom- und Molekülphysik Detector Characterization of GEO 600 during the S4 science run S. Hild for the GEO 600 team Introduction  GEO 600 participated in the LSC S4 science run, which took place between February 22 nd and March 24 th  During these 708 hours a duty cycle in nominal science mode of 96.6 % was achieved.  Many monitors for detector characterization were developed and used for commissioning before S4 as well as for online detector characterization during the science run. Typical sensitivity Detector Characterization Tools Lock-loss investigations Data Quality Every loss of lock during S4 was analysed ! Signals used for lock-loss investigations: Logitudinal error points and feedback points of modecleaners, Power Recycling, Signal Recycling and differential Michelson. (whitened and unwhitened signals) Autoalignment error points and feedback points of modecleaners, Power Recycling, Signal Recycling and differential Michelson. Laser power stabilisation loop Light powers at various points of the interferometer Environmental monitors For future: Monitoring of important RF-modulation signals Instrumental duty cycle = % Longest lock > 52 hours Instrumental duty cycle for locks longer than 10 hours = % Usually used for Burst analysis: lock segments > 300 seconds Usually used for Inspiral analysis: lock segments > 2048 seconds h(t): derived from two quadratures of MI diff. EP diff. calibration: estimation of optical gain + MID loop gain (for online calibration) noise proj.: calibration lines for various online noise projections violin mode: fiber modes from the monolithic suspension stage MC turbo: turbo pump frequency (822 Hz) Mains: 50 Hz and multiples from mains The signal recycling mirror was tuned for a peak response at 1 kHz. Sensitivity corresponds to range of about 0.4 MPc for BH-BH inspirals (about 0.25 MPc for BH-NS and NS-NS). Duty Cycle Reason for locklossquantity Tractor passing east or north building35 High frequency glitches in power-stab loop25 Maintenance Hz oscillation in MID-AA-Tilt16 Stormy weather14 Earthquakes5 12 Hz oscillation in MID-long-loop5 Coupled ringing in SR-AA and MID-long3 Modecleaner 1 oscillation 30 Hz2 Horse galloping along north building2 End of range1 Unlear4 Total134 Exemplary lock loss investigation: 2.5 Hz oscillation MID-AA-Tilt 1 kHz SeismoMon IFOMonHspecmon Online h(t), with min/max per frequency bin Spectra of seismic (9 degrees of freedom) IFO channels potentially coupling to h(t) There was one stormy day in S4: Wind shakes the walls of the buildings  causes acoustic noise inside the buildings  movement of walls couples via foundation to vacuum system Large misalignment (Michelson auto- alignment is gain pendulum resonance frequencies) Non-optimal spatial overlap of beams at the beamsplitter Increased light level at the dark port and on detection photodiode Saturation of MI diff EP in electronics Windy conditions 2 Volts = Saturation Found a perfect correlation between BLRMS (989 to 999 Hz) of h(t) and the rate of glitches with a central frequency between 700 and 2000 Hz. Some properties of the glitches (derived from HACRmon): glitches cause excess noise between 400 and 1300 Hz average duration of about 20 ms average bandwidth of about 200 Hz Glitch rate varies from nearly 0 to 4000 glitches per 15 minutes GEO REPORTS Min/max spectrum of h(t) 15 BLRMS of h(t) Inspiral monitor Spectrogram of h(t) Data quality Chi 2 Calibration parameters Bursts (HACRmon): Lines (Linemon): Sensitivity: Calibration Time frequency distribution SNR distribution Duration Bandwidth Line cataloguing Harmonic identification Sideband identification Data Quality Flags: 1. Chi 2 Derived from calibration process (compares model and measurement of the optical gain at calibration line frequencies) Used to flag MU3-Glitches 2. Saturation of detection signal Used to flag bad times due to stormy weather 3. Seismic flag (planned) Flag for high level of local seismic noise (tractors passing buildings) MU3-Glitches Windy day Tractor activities Chi 2 cut HACRmon 1kHz chi 2 Example: MU3-Glitches (Problem was fixed during S4) Glitchrate (HACRmon) Strain RMS Glitchrate (HACRmon) Chi 2 : derived from calibration process a.u. Voltage [V] [m/s]