Cumming, A.V., Sorazu, B., Daw, E. orcid.org/0000-0002-3780-5430 et al. (7 more authors) (2020) Lowest observed surface and weld losses in fused silica fibres for gravitational wave detectors. Classical and Quantum Gravity, 37 (19). 195019. ISSN 0264-9381
Abstract
High purity fused silica has become the cornerstone choice for use in the final monolithic stage of the mirror suspensions in the gravitational wave observatories Advanced LIGO (aLIGO) and Advanced Virgo (AdV). The ultra-low thermal noise contributed by these suspensions is one of the key improvements that permitted the Nobel prize winning first direct measurement of gravitational waves in 2015. This paper outlines the first in situ study undertaken to analyse the thermal noise of the final monolithic stage of the aLIGO Hanford detector mirror suspensions. We analysed short operational periods of this detector, when high excitation of the transverse 'violin' modes of the silica suspension fibres occurred. This allowed detailed measurements of the Q-factor of violin modes up to order 8 of individual fibres on separate masses. We demonstrate the highest silica fibre violin mode Q-factors yet measured of up to 2 × 109. From finite element modelling, the dominant surface and weld losses have been calculated to be a factor of 3 to 4 better than previously accepted, and as a result, we demonstrate that the level of noise in the aLIGO final stage silica suspensions is around 30%–40% better than previously estimated between frequencies of 10–500 Hz. This leads to an increase in the estimated event rate by a factor of 2 for aLIGO, if suspension thermal noise became the main limitation to the sensitivity of the detector.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2020 The Author(s). Published by IOP Publishing Ltd. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI (http://creativecommons.org/licenses/by/4.0). |
Keywords: | aLIGO; suspensions; monolithic; fused silica; mechanical loss; dissipation |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Physics and Astronomy (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 20 Oct 2020 10:29 |
Last Modified: | 20 Oct 2020 10:29 |
Status: | Published |
Publisher: | IOP Publishing |
Refereed: | Yes |
Identification Number: | 10.1088/1361-6382/abac42 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:166711 |
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