A 'Violin-Mode' shadow sensor for interferometric gravitational wave detectors

Lockerbie, N A and Tokmakov, K V (2014) A 'Violin-Mode' shadow sensor for interferometric gravitational wave detectors. Measurement Science and Technology, 25 (12). 125110. ISSN 0957-0233 (https://doi.org/10.1088/0957-0233/25/12/125110)

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Abstract

This paper describes a system of four novel shadow detectors having, collectively, a displacement sensitivity of (69 ± 13) picometres (rms) / √Hz, at 500 Hz, over a measuring span of ±0.1 mm. The detectors were designed to monitor the vibrations of the 600 mm long, 400 µm diameter, silica suspension fibres of the mirrors for the Advanced LIGO (Laser Interferometer Gravitational wave Observatory) gravitational wave detectors, at the resonances of the so-called Violin Modes (VM). The VM detection system described here had a target sensitivity of 100 pm (rms)/√Hz at 500 Hz, together with, ultimately, a required detection span of ±0.1 mm about the mean position of each fibre—in order to compensate for potential slow drift over time of fibre position, due to mechanical relaxation. The full sensor system, comprising emitters (sources of illumination) and shadow detectors, therefore met these specifications. Using these sensors, VM resonances having amplitudes of 1.2 nm (rms), were detected in the suspension fibres of an Advanced LIGO dummy test-mass. The VM bandwidth of the sensor, determined by its transimpedance amplifier, was 226 Hz–8.93 kHz at the —3 dB points. This paper focuses mainly on the detector side of the shadow-sensors. The emitters are described in an accompanying paper.

ORCID iDs

Lockerbie, N A ORCID logoORCID: https://orcid.org/0000-0002-1678-3260 and Tokmakov, K V ORCID logoORCID: https://orcid.org/0000-0002-2808-6593;
  • Item type:Article
    ID code:50014
    Dates:
    Date
    Event
    7 November 2014
    Published
    7 November 2014
    Published Online
    7 October 2014
    Accepted
    Subjects:Science > Physics
    Department:Faculty of Science > Physics
    Depositing user: Pure Administrator
    Date deposited:24 Oct 2014 10:07
    Last modified:21 Nov 2024 01:09
    Related URLs:
    URI:https://strathprints.strath.ac.uk/id/eprint/50014
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