[en] This paper describes the microwave properties of a sapphire loaded superconducting cavity resonator. We report measurements of energy confinement, evanescent field scale lengths, and radiation losses. We report high quality factors, in excess of 10⁹ at cryogenic temperatures, for a resonator based on a sapphire element mounted inside a superconducting cavity. Resonators of this type have potentially valuable applications as ultrahigh stability oscillators, high Q filters and as low phase noise frequency sources

[en] In this paper, the author discusses the present generation of cryogenic Weber-bar antennae for gravitational waves. Successively are discussed signal strength and event rate; intrinsic noise in resonant antennae; transducers for resonant mass antennae; antennae materials; suspension and isolation; and prospects for improved sensitivity. (Auth.)

[en] This paper reviews the concept of gravitational radiation, and describes the worldwide research programme for the development of high-sensitivity resonant-bar antennas which are aimed at detecting gravitational radiation from astrophysical sources. (author)

[en] A mechanism of non-linear excitation is proposed to explain observed excess noise in gravitational radiation antennae, driven by low frequency vibration. The mechanism is analogous to the excitation of a violin string by low frequency bowing. Numerical estimates for Weber bars suspended by cables are in good agreement with observations. (Auth.)

[en] A negative result for a highly sensitive measurement to detect changes in the helium film thickness profile induced by torsional oscillation of the film substrate is reported. The results are in agreement with Keller's failure to detect film thinning, but are in disagreement with recent results of Williams and Packard, Graham and Vittoratos, and Hallock. (2 figures) (auth)

[en] This paper reviews the development of gravitational radiation antennas. Major problems still to be overcome are outlined, and prospects for the detection of gravitational radiation from astrophysical sources are discussed. Major emphasis is placed on Weber bar antennas, with spacecraft Doppler ranging and laser interferometer antennas discussed briefly

No abstract available

No abstract available

[en] An automatic superconducting flux pump is described capable of energizing an inductive load to high currents (approximately 1000 A). These currents are derived from an inexpensive low current power supply and control circuits. (U.S.)

[en] A superconducting-cavity stabilised oscillator has been constructed which combines active and passive stabilisation of a 9.6 GHz klystron to obtain a phase noise power spectral density between -170 dB Hz^-₁ and -180 dB Hz^-₁ at 5 kHz from the carrier, which represents about 40 dB improvement over the state-of-the-art. The device has been developed for use as a low noise pump for a superconducting parametric upconverter transducer on a gravitational radiation antenna. An RF modulated reflex klystron is actively locked to a TE⁰¹¹ niobium cavity operated at 2 K with a loaded Q of the order of 10₈. Power is extracted from the cavity which acts as a high Q filter. (author)