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تسجيل مستخدم جديدLaser-interferometric Detectors for Gravitational Wave Background at 100 MHz : Detector Design and Sensitivity
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Recently, observational searches for gravitational wave background (GWB) have developed and given direct and indirect constraints on the energy density of GWB in a broad range of frequencies. These constraints have already rejected some theoretical models of large GWB spectra. However, at 100 MHz, there is no strict upper limit from direct observation, though the indirect limit by He4 abundance due to big-bang nucleosynthesis exists. In this paper, we propose an experiment with laser interferometers searching GWB at 100 MHz. We considered three detector designs and evaluated the GW response functions of a single detector. As a result, we found that, at 100 MHz, the most sensitive detector is the design, a so-called synchronous recycling interferometer, which has better sensitivity than an ordinary Fabry-Perot Michelson interferometer by a factor of 3.3 at 100 MHz. We also give the best sensitivity achievable at 100 MHz with realistic experimental parameters.
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Recently, observational searches for gravitational wave background (GWB) have been developed and given constraints on the energy density of GWB in a broad range of frequencies. These constraints have already resulted in the rejection of some theoreti
cal models of relatively large GWB spectra. However, at 100 MHz, there is no strict upper limit from direct observation, though an indirect limit exists due to He4 abundance due to big-bang nucleosynthesis. In our previous paper, we investigated the detector designs that can effectively respond to GW at high frequencies, where the wavelength of GW is comparable to the size of a detector, and found that the configuration, a so-called synchronous-recycling interferometer is best at these sensitivity. In this paper, we investigated the optimal location of two synchronous-recycling interferometers and derived their cross-correlation sensitivity to GWB. We found that the sensitivity is nearly optimized and hardly changed if two coaligned detectors are located within a range 0.2 m, and that the sensitivity achievable in an experiment is far below compared with the constraint previously obtained in experiments.
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