Tilt-free seismometer


Seismic noise is one of the major sources of noise for Laser Interferometer Gravitational-wave Observatory (LIGO). Isolating the system (e.g. interferometer mirrors) from ground motion reduces the seismic noise. Different sensors such as inertial sensors are used to monitor these disturbances and take part in a feedback or feedforward control system. The tilt-horizontal coupling in inertial sensors is one of the major problems for seismic isolation in low frequencies. The signal of inertial sensors is dominated by tilt motion at low frequencies and our goal is to decouple the translational and tilt information. There are two broad categories of a solution:
  • Use inertial rotation sensors and subtract the tilt component from the signal of horizontal inertial sensors. But this solution is restricted by the noise level of rotational sensors.
  • Mechanically filter the tilt transmission to the sensor by suspending an inertial sensor.
This wiki contains relevant information that we wish to regularly access related to our work on a solution for the second approach.


Student reports

Relevant Publications

  • Peter W. Rodgers, "Frequency limits for seismometers as determined from signal-to-noise ratios." Bulletin of the Seismological Society of America, Vol. 82, No. 2 (1992)
  • Wielandt and Streckheisen, "The leaf-spring seismometer: design and performance." Bulletin of the Seismological Society of America, Vol. 72, No. 6 (1982)
  • "Modeling and experiment of the suspended seismometer concept for attenuating the contribution of tilt motion in horizontal measurements" by Matichard, et al. 2016 arXiv
  • Henri Sohier, "Suspension of a seismometer for improved sensitivity by tilt sensitivity limitation" LIGO-E1100229
  • "Dynamical Properties of LIGO Single Loop Suspended Mirrors" by Malik Rakhmanov LIGO-T000134
  • Ringler and Hutt, "Self-noise models of seismic instruments"
  • L-4C geophone service manual, which includes calibration instructions
  • Frequency limits for seismometers as determined from signal-to-noise ratios: The electromagnetic seismometer.
  • Review: Inertial Sensors for Low-Frequency Seismic Vibration Measurement: Link
  • Response of Seismometer with Symmetric Triaxial Sensor Configuration to Complex Ground Motion: Researchgate

Relevant Topics

  • Inertial Sensors: In this topic, you will find a brief explanation of different types of inertial sensors.


Topic revision: r14 - 21 Sep 2017, MohammadAfrough
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