A low-noise transimpedance amplifier for the detection of “Violin-Mode” resonances in advanced laser interferometer gravitational wave observatory suspensions

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Lockerbie, N. A. and Tokmakov, K. V. (2014) A low-noise transimpedance amplifier for the detection of “Violin-Mode” resonances in advanced laser interferometer gravitational wave observatory suspensions. Review of Scientific Instruments, 85 (11). 114705. ISSN 0034-6748 (https://doi.org/10.1063/1.4900955)

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Abstract

This paper describes the design and performance of an extremely low-noise differential transimpedance amplifier, which takes its two inputs from separate photodiodes. The amplifier was planned to serve as the front-end electronics for a highly sensitive shadow-displacement sensing system, aimed at detecting very low-level “Violin-Mode” (VM) oscillations in 0.4 mm diameter by 600 mm long fused-silica suspension fibres. Four such highly tensioned fibres support the 40 kg test-masses/mirrors of the Advanced Laser Interferometer Gravitational wave Observatory interferometers. This novel design of amplifier incorporates features which prevent “noise-gain peaking” arising from large area photodiode (and cable) capacitances, and which also usefully separate the DC and AC photocurrents coming from the photodiodes. In consequence, the differential amplifier was able to generate straightforwardly two DC outputs, one per photodiode, as well as a single high-gain output for monitoring the VM oscillations—this output being derived from the difference of the photodiodes’ two, naturally anti-phase, AC photocurrents. Following a displacement calibration, the amplifier’s final VM signal output was found to have an AC displacement responsivity at 500 Hz of (9.43 ± 1.20) MV(rms) m−1(rms), and, therefore, a shot-noise limited sensitivity to such AC shadow- (i.e., fibre-) displacements of (69 ± 13) picometres/√Hz at this frequency, over a measuring span of ±0.1 mm.

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:51121
    Dates:
    Date
    Event
    7 November 2014
    Published
    7 November 2014
    Published Online
    21 October 2014
    Accepted
    Subjects:Science > Physics
    Department:Faculty of Science > Physics
    Depositing user: Pure Administrator
    Date deposited:15 Jan 2015 15:14
    Last modified:02 Dec 2024 01:15
    Related URLs:
    URI:https://strathprints.strath.ac.uk/id/eprint/51121
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