131 research outputs found
Passive Newtonian noise suppression for gravitational-wave observatories based on shaping of the local topography
In this article we propose a new method for reducing Newtonian noise in
laser-interferometric gravitational-wave detectors located on the Earth's
surface. We show that by excavating meter-scale recesses in the ground around
the main test masses of a gravitational wave detector it is possible to reduce
the coupling of Rayleigh wave driven seismic disturbances to test mass
displacement. A discussion of the optimal recess shape is given and we use
finite element simulations to derive the scaling of the Newtonian noise
suppression with the parameters of the recess as well as the frequency of the
seismic excitation. Considering an interferometer similar to an Advance LIGO
configuration, our simulations indicate a frequency dependent Newtonian noise
suppression factor of 2 to 4 in the relevant frequency range for a recesses of
4m depth and a width and length of 11m and 5m, respectively. Though a retrofit
to existing interferometers seems not impossible, the application of our
concept to future infrastructures seems to provide a better benefit/cost ratio
and therefore a higher feasibility.Comment: 12 pages, 5 figure
Beyond the Second Generation of Laser-Interferometric Gravitational Wave Observatories
This article gives an overview of potential upgrades of second generation
gravitational wave detectors and the required key technologies to improve the
limiting noise sources. In addition the baseline design of the Einstein
Telescope, a European third generation gravitational wave observatory, is
briefly discussed.Comment: Amaldi 9 proceeding
Experimental demonstration of a Displacement noise Free Interferometry scheme for gravitational wave detectors showing displacement noise reduction at low frequencies
This paper reports an experimental demonstration of partial displacement
noise free laser interferometry in the gravitational wave detection band. The
used detuned Fabry-Perot cavity allows the isolation of the mimicked
gravitational wave signal from the displacement noise on the cavities input
mirror. By properly combining the reflected and transmitted signals from the
cavity a reduction of the displacement noise was achieved. Our results
represent the first experimental demonstration of this recently proposed
displacement noise free laser interferometry scheme. Overall we show that the
rejection ratio of the displacement noise to the gravitational wave signal was
improved in the frequency range of 10 Hz to 10 kHz with a typical factor of 60.Comment: 5 pages, 3 figure
Prospects of higher-order Laguerre Gauss modes in future gravitational wave detectors
The application of higher-order Laguerre Gauss (LG) modes in large-scale
gravitational wave detectors has recently been proposed. In comparison to the
fundamental mode, some higher-order Laguerre Gauss modes can significantly
reduce the contribution of coating Brownian noise. Using frequency domain
simulations we give a detailed analysis of the longitudinal and angular control
signals derived with a LG33 mode in comparison to the fundamental TEM00 mode.
The performance regarding interferometric sensing and control of the LG33 mode
is found to be similar, if not even better in all aspects of interest. In
addition, we evaluate the sensitivity gain of the implementation of LG33 modes
into the Advanced Virgo instrument. Our analysis shows that the application of
the LG33 mode results in a broadband improvement of the Advanced Virgo
sensitivity, increasing the potential detection rate of binary neutron star
inspirals by a factor 2.1.Comment: 12 pages, 8 figure
Length sensing and control for Einstein Telescope Low Frequency
In this paper we describe a feasible length sensing and control scheme for the low frequency interferometers of the Einstein Telescope (ET-LF) along with the techniques used to optimise several optical parameters, including the length of the recycling cavities and the modulation frequencies, using two numerical interferometer simulation packages: Optickle and Finesse. The investigations have suggested the use of certain combinations of sidebands to obtain independent information about the different degrees of freedom
Beyond the first generation : extending the science range of the gravitational wave detector GEO 600
[no abstract
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