The Status of GEO600

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The Status of GEO600

• Joshua Smith for the GEO 600 team

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Recent Work (Examples)

• Increasing Robustness Detector
• More Digital Control (with dSPACE)
• Implemented on Signal-recycling longitudinal and
  Michelson Auto-alignment control loops
• allows aggressive filtering of detection noise
  limited feedback signals, notching, resonant gain
• Increased MI gain More stable locks (less
  saturations in MI loop), less modulation of
  signals
• New de/modulation setup from lemo to SMA,
  quality components
• Changed laser and increased power (full input
  Pwr)
• Radiation pressure compensation in modecleaners
• Increasing data quality
• Elimination of 1s glitches by lowpassing cal.
  parameters
• Scattering on SR Bench (Again!)

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Sensitivity
Peak 5e-22
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Inspiral Range
Design BH-BH 42MPc, for optimal position
(factor 5/2 higher)
http//www.geo600.uni-hannover.de/georeports/
MPc
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Noise Projections hP
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Work Ahead, S5 Plans

• Period of intense noise hunting
• Overnight and weekend runs
• Best guess around Christmas
• With well-calibrated detector output
• Join S5
• When additional improvements will take too long
  or are too risky to implement

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The End!
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Optical Layout
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SR FB analog vs. digital
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New MI longitudinal loop
Old

New Much more gain _at_ low f
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Start-of-the-second glitches
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Bennos Email

• We plan to join S5 as early as possible in an
  overnight/weekend mode. In this mode we will work
  on the detector during the daytime. In the
  evening we make sure that the calibration process
  is running reliably and we will provide
  callibrated h(t) data and a data quality channel.
  All analyses that make their own data quality cut
  and do not rely on instrumental vetoes might find
  these data useful. In this mode all other
  detector and environmental channels will be of
  limited reliabilty and possibly of limited
  quality.
• We are working hard to implement a number of
  changes that have been identified as necessary
  during noise hunting work. The most urgent ones
  involve changes to the Michelson length control
  loop. As this work affects the calibration
  parameters we are not confident to provide h(t)
  until the changes in the MI loop are finished and
  we have a stable confirmed calibration again. Our
  best guess is that we will join S5 in the
  overnight/weekend mode around Christmas.
• We will continue commissioning until we feel
  additional improvements will take too long or are
  too risky and then join S5 in a 24/7 mode.

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Nonlinear Actuator Up-con
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Nonlinear Actuator Beats
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Nonlinear Noise vs. Bias 600V
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Nonlinear Noise vs. Bias 60V
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Nonlinear Noise vs Bias V
Further decrease in bias not optimal !