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  • 1
    Electronic Resource
    Electronic Resource
    Development of a 1.5-tonne niobium gravitational radiational antenna (1987)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 58 (1987), S. 1910-1916 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A 1.5-tonne Nb gravitational radiation antenna is described. Problems associated with a noncontacting magnetically levitated parametric upconverter transducer are discussed, and a system using a bonded microwave reentrant cavity and bonded mechanical impedance transformer is described and analyzed in detail. It is shown that such an antenna can be expected to achieve a noise temperature of ∼1 mK. An ultralow phase noise tunable microwave source for the transducer pump signal is described, as well as precision bonding techniques which yield a mechanical positioning accuracy of 10−6 m, and a reproducibility of 10−8 m.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1139488
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  • 2
    Electronic Resource
    Electronic Resource
    Parametric interaction of the electric and acoustic fields in a sapphire monocrystal transducer with a microwave readout (1998)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 84 (1998), S. 6523-6527 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A sapphire monocrystal configured with a parametric microwave readout can potentially monitor the motion of its internal acoustic resonances at the precision governed by quantum mechanical fluctuations. The mechanism of transductance is due to parametric interaction between the electric and acoustic field within the crystal. This mechanism has been tested for the first time, and the theory has been verified by observing the pump frequency dependence of the acoustic quality factor. Because of the extremely low acoustic losses (Q〉107) and electrical losses (Q〉104), measurements were sensitive enough to attain positive verification at room temperature. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.369023
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  • 3
    Electronic Resource
    Electronic Resource
    Low resonant frequency cantilever spring vibration isolator for gravitational wave detectors (1994)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 3482-3488 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An all metal multistage low frequency vibration isolator for a laser interferometer gravitational wave detector has been built and tested with a very sensitive accelerometer. Curved cantilever springs are used to form a low frequency compact form of isolation element. Near center of mass suspension of the isolation stages reduces cross coupling between orthogonal directions. The isolator has a low-pass corner frequency of 6.5 Hz vertically and 1.8 Hz horizontally. The system shows low temperature coefficients and absence of creep. Results demonstrate that steel curved springs near their elastic limit do not generate broadband acoustic noise at the 10−15 m /(square root of)Hz level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1145218
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  • 4
    Electronic Resource
    Electronic Resource
    Microwave signal processing for a cryogenic gravitational radiation antenna with a noncontacting readout (1993)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3191-3197 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A modified version of the microwave signal processing system for the 1.5 tonne niobium bar gravitational radiation antenna at the University of Western Australia has been developed and tested during preparations for long-term observation. Among the new features of the system are a noncontacting microwave coupling to the motion transducer, cryogenic low-noise amplification, and automatic carrier suppression with improved long-term stability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1144327
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  • 5
    Electronic Resource
    Electronic Resource
    Southern Hemisphere automated supernova search (1995)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 2777-2784 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The Perth Astronomy Research Group has developed an automated supernova search program, using the 61 cm Perth–Lowell reflecting telescope at Perth Observatory in Western Australia, equipped with a CCD camera. The system is currently capable of observing about 15 objects per hour, using 3 min exposures, and has a detection threshold of 18th–19th magnitude. The entire system has been constructed using low-cost IBM-compatible computers. Two original discoveries (SN 1993K, SN 1994R) have so far been made during automated search runs. This paper describes the hardware and software used for the supernova search program, and shows some preliminary results from the search system. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1145624
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  • 6
    Electronic Resource
    Electronic Resource
    Noncontacting microwave coupling to a cryogenic gravitational radiation antenna (1993)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1905-1909 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Gravitational radiation detectors must detect extremely small displacements, and thus require elaborate vibration isolation systems to attenuate the surrounding environmental noise. Contacting electrical leads can provide a direct path that will short circuit the vibration isolation, and degrade the antenna Q factor. Noncontacting microstrip transceivers provide a practical means of electromagnetically coupling to a resonant bar gravitational antenna when a microwave transducer is used as a signal readout system. Two microwave patch antennas now operate as transceivers on the University of Western Australia's 1.5 tonne niobium bar gravitational radiation antenna and are described in detail in this paper. This system allows improved vibration isolation without degradation of the acoustic Q factor of the niobium bar. Combined with a cryogenic amplifier, this system should achieve a reduction of 57 dB in the series noise power. This corresponds to a factor of 700 reduction in the effective displacement noise when referred to the transducer, from 2×10−16 to 3×10−19 m/(square root of)Hz.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1143975
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  • 7
    Electronic Resource
    Electronic Resource
    Parametric back-action effects in a high-Q cyrogenic sapphire transducer (1996)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 2435-2442 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The construction and operation of a high-quality factor microwave sapphire resonator transducer coupled to a 1 kHz niobium membrane acoustic oscillator are presented in this paper. A four-stage passive vibration isolation system was included in the design to permit the measurement of the transducer's parametric properties. The isolation system was shown to sufficiently suppress mechanical noise above 100 Hz and an upper limit to the displacement sensitivity of the transducer was measured to be 3.0±0.6×10−16 m/(square root of)Hz. The parametric behavior of the transducer with a single pump readout was measured for several transducer configurations, and the results were found to be in good agreement with theory. The measurements presented here display for the first time the complete parametric behavior in a high electrical Q system, where the transducer's bandwidth is less than the mechanical oscillator's frequency. The high stability and low losses of our system may allow the transducer to be configured as a back-action evasion or quantum nondemolition device. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1147193
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  • 8
    Electronic Resource
    Electronic Resource
    Position control system for suspended masses in laser interferometer gravitational wave detectors (1995)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 2763-2776 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We review and present an analysis of the major issues in the design of test mass control systems for laser interferometer gravitational wave detectors. Based on this analysis, we present a design for a computer controlled modular analog servo control system which is well suited to the control of a large number of degrees of freedom in long baseline instruments. The system has been tested on an interferometer using multistage cantilever spring isolators. The system enables simple monitoring, testing, and display of many channels simultaneously, while retaining the advantages of analog proportional-integral-derivative control electronics. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1145623
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  • 9
    Electronic Resource
    Electronic Resource
    Application of commercial antennas to very long baseline interferometry radio astronomy (1995)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 995-999 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Groundstation antennas located in Western Australia have been used as elements in the Southern Hemisphere very long baseline interferometry (VLBI) experiment. These commercial antennas of 27.5 and 15 m diameter provide a very economical improvement to the imaging capability of this array and the practice of using such antennas can be extended to other sites in the Southern Hemisphere in preparation for the forthcoming space-VLBI experiments. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1145634
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  • 10
    Electronic Resource
    Electronic Resource
    Ultrahigh Q pendulum suspensions for gravitational wave detectors (1993)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1899-1904 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Pendulum suspensions for laser interferometer gravitational wave detectors need to have an extremely high Q factor to minimize Brownian motion noise. In this paper we analyze the limits to the Q factor of the compound pendulum. We show that the observed acoustic loss of niobium can allow pendulum Q factors of 1010 to be achieved. This should enable a 3 km terrestrial laser interferometer detector to achieve strain sensitivity of 10−22/(square root of)Hz at frequencies as low as 10 Hz. At cryogenic temperatures Q factors up to 1012 should be achievable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1143974
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