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Quadruple suspension design for Advanced LIGO

Robertson, N. A. and Cagnoli, G. and Crooks, D. R. M. and Elliffe, E. and Faller, J. E. and Fritschel, P. and Goβler, S. and Grant, A. and Heptonstall, A. and Hough, J. and Lück, H. and Mittleman, R. and Perreur-Lloyd, M. and Plissi, M. V. and Rowan, S. and Shoemaker, D. H. and Sneddon, P. H. and Strain, K. A. and Torrie, C. I. and Ward, H. and Willems, P. (2002) Quadruple suspension design for Advanced LIGO. Classical and Quantum Gravity, 19 (15). pp. 4043-4058. ISSN 0264-9381. doi:10.1088/0264-9381/19/15/311.

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In this paper, we describe the conceptual design for the suspension system for the test masses for Advanced LIGO, the planned upgrade to LIGO, the US laser interferometric gravitational-wave observatory. The design is based on the triple pendulum design developed for GEO 600—the German/UK interferometric gravitational wave detector. The GEO design incorporates fused silica fibres of circular cross-section attached to the fused silica mirror (test mass) in the lowest pendulum stage, in order to minimize the thermal noise from the pendulum modes. The damping of the low-frequency modes of the triple pendulum is achieved by using co-located sensors and actuators at the highest mass of the triple pendulum. Another feature of the design is that global control forces acting on the mirrors, used to maintain the output of the interferometer on a dark fringe, are applied via a triple reaction pendulum, so that these forces can be implemented via a seismically isolated platform. These techniques have been extended to meet the more stringent noise levels planned for in Advanced LIGO. In particular, the Advanced LIGO baseline design requires a quadruple pendulum with a final stage consisting of a 40 kg sapphire mirror, suspended on fused silica ribbons or fibres. The design is chosen to aim to reach a target noise contribution from the suspension corresponding to a displacement sensitivity of 10^(−19) m Hz^(−1/2) at 10 Hz at each of the test masses.

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Additional Information:© 2002 IOP Publishing Ltd. Received 10 May 2002. Published 15 July 2002. The authors would like to thank their colleagues in the GEO collaboration for their interest and help in this work. We also acknowledge with thanks members of the LIGO Scientific Collaboration (LSC) at Caltech, MIT and Stanford who have contributed, in particular Mark Barton at Caltech. The Glasgow group acknowledges the financial support of the University of Glasgow. GEO acknowledges the financial support of the Particle Physics and Astronomy Research Council (PPARC), the Bundesministerium für Bildung und Forschung (BMBF) and the state of Lower Saxony. The LIGO Laboratory thanks the National Science Foundation for its support through the cooperative agreement PHY-9210038 and the award PHY-9801158.
Funding AgencyGrant Number
University of GlasgowUNSPECIFIED
Particle Physics and Astronomy Research Council (PPARC)UNSPECIFIED
Bundesministerium für Bildung und Forschung (BMBF)UNSPECIFIED
State of Lower SaxonyUNSPECIFIED
NSF Cooperative AgreementPHY-9210038
NSF Cooperative AgreementPHY-9801158
Issue or Number:15
Classification Code:PACS: 04.80Nn. MSC: 83C35
Record Number:CaltechAUTHORS:20140110-085940181
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Official Citation: Quadruple suspension design for Advanced LIGO N A Robertson et al 2002 Class. Quantum Grav. 19 4043
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:43304
Deposited By: Ruth Sustaita
Deposited On:10 Jan 2014 17:47
Last Modified:10 Nov 2021 16:36

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