Mechanical characterisation of the TorPeDO: a low frequency gravitational force sensor. (5th June 2017)

• Record Type: Journal Article
• Authors: McManus, D J; Forsyth, P W F; Yap, M J; Ward, R L; Shaddock, D A; McClelland, D E; Slagmolen, B J J
• Is Part Of: Classical and quantum gravity. Volume 34:Number 13(2017:Jul.)
• Publication Date: 2017-06-05
• Subjects: gravitational waves -- newtonian noise -- torsion pendulum -- optical sensing -- gravimeter; Quantum gravity -- Periodicals; Gravitation -- Periodicals; Relativity (Physics) -- Periodicals; Space and time -- Periodicals; Periodicals; 521.1
• DOI: 10.1088/1361-6382/aa7103
• Languages: English
• ISSNs: 0264-9381

Abstract

Abstract: Newtonian noise is likely to be a future challenge at low frequencies for Advanced LIGO and other second generation gravitational wave detectors. We present the TorPeDO system: a dual torsion pendulum sensor designed to measure local gravitational forces to high precision. Gravitational forces induce a differential rotation between the two torsion beams, which is measured with an optical read-out. Both torsion pendulums have a common suspension point, tunable centre of mass, and resonant frequency. This produces a high level of mechanical common mode noise cancellation. We report on a controls prototype of the TorPeDO system, presenting the frequency response and tuning range of both pendulums. A noise budget and mechanical cross-coupling model for this system are also presented. We demonstrate frequency tuning of the two torsion pendulums to a difference of 4.3 μ Hz.