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Experiments with a Laser Interferometric Gravitational Wave Antenna


Zucker, Michael Edward (1989) Experiments with a Laser Interferometric Gravitational Wave Antenna. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/T5D0-4N31.


Sources and effects of astrophysical gravitational radiation are explained briefly to motivate discussion of the Caltech 40 meter antenna, which employs laser interferometry to monitor proper distances between inertial test masses. Practical considerations in construction of the apparatus are described. Redesign of test mass systems has resulted in a reduction of noise from internal mass vibrations by up to two orders of magnitude at some frequencies. A laser frequency stabilization system was developed which corrects the frequency of an argon ion laser to a residual fluctuation level bounded by the spectral density √sν(f) ≤ 60 µHz/√Hz, at fluctuation frequencies near 1.2 kHz. These and other improvements have contributed to reducing the spectral density of equivalent gravitational wave strain noise to √Sh(f) ≈ 10⁻¹⁹/√ Hz at these frequencies.

Finally, observations made with the antenna in February and March of 1987 are described. Kilohertz-band gravitational waves produced by the remnant of the recent supernova are shown to be theoretically unlikely at the strength required for confident detection in this antenna (then operating at poorer sensitivity than that quoted above). A search for periodic waves in the recorded data, comprising Fourier analysis of four 105-second samples of the antenna strain signal, was used to place new upper limits on periodic gravitational radiation at frequencies between 305 Hz and 5 kHz. In particular, continuous waves of any polarization are ruled out above strain amplitudes of 1.2 x 10⁻¹⁸ R.M.S. for waves emanating from the direction of the supernova, and 6.2 x 10⁻¹⁹ R.M.S. for waves emanating from the galactic center, between 1.5 and 4 kilohertz. Between 305 Hz and 5kHz no strains greater than 1.2 x 10⁻¹⁷ R.M.S. were detected from either direction. Limitations of the analysis and potential improvements are discussed, as are prospects for future searches.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:LIGO, laser, interferometer, gravitational, gravity
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Drever, Ronald W. P.
Group:Astronomy Department, LIGO
Thesis Committee:
  • Drever, Ronald W. P. (chair)
  • Phinney, E. Sterl
  • Prince, Thomas A.
  • Gomez, Ricardo
Defense Date:1 July 1988
Record Number:CaltechTHESIS:10252013-143448203
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:8012
Deposited By: Dan Anguka
Deposited On:25 Oct 2013 22:15
Last Modified:12 Jan 2022 01:41

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