Showing papers by "G. Gemme published in 2006"
TL;DR: In this article, the authors report on the present scientific run (04-05) of the two detectors EXPLORER and NAUTILUS, which started in March 2004.
Abstract: We report on the present scientific run (04–05) of the two detectors EXPLORER and NAUTILUS. The 04–05 run of the two detectors started in March 2004. The strain sensitivity is about 7 × 10−22 Hz−1/2 and the bandwidth is about 5 Hertz. The sensitivity for 1 ms bursts is h = 3 × 10−19.
26 citations
TL;DR: In this paper, the authors reported the preliminary results of the search for gravitational wave bursts from the 2003 run of the EXPLORER-NAUTILUS experiment and derived a new upper limit for the GW burst rate, of the order of 0.02 events/day for hRSS ≥ 2 × 10−19.
Abstract: We report here the preliminary results of the search for gravitational wave bursts from the 2003 run of the EXPLORER–NAUTILUS experiment. The total common measuring time was 149 days. The detectors had a typical noise spectral amplitude of about 2 × 10−21 Hz−1/2, a bandwidth of the order of 10 Hz and a very good stability. We derive a new upper limit for the GW burst rate, of the order of 0.02 events/day for hRSS ≥ 2 × 10−19, and discuss the implication of this result with respect to the results obtained with the 2001 run.
9 citations
02 Mar 2006
TL;DR: In this article, the authors developed a fully coupled dynamic model of the system and worked out some estimates of signal-to-noise ratio and the stability conditions in various experimental configurations.
Abstract: Parametric transducers, such as superconducting rf cavities, can boost the bandwidth and sensitivity of the next generation resonant antennas, thanks to a readily available technology. We have developed a fully coupled dynamic model of the system ''antenna- transducer'' and worked out some estimates of signal-to-noise ratio and the stability conditions in various experimental configurations. We also show the design and the prototype of a rf cavity which, together with a suitable read-out electronic, will be used as a test bench for the parametric transducer.
5 citations
TL;DR: In this paper, a microwave parametric transducer is proposed to be installed on massive gravity wave antennas, like bars and spheres, based on the high sensitivity of a superconducting RF cavity to the change of the appropriate geometrical dimension.
Abstract: We are developing a microwave parametric transducer to be installed on massive gravity wave antennas, like bars and spheres. This transducer is based on the high sensitivity of a superconducting RF cavity to the change of the appropriate geometrical dimension. To fully exploit the transducer sensitivity, a very low noise amplifier, at the operating frequency of a few GHz, is required. We describe the experimental set-up and the test procedure that has been used to measure the noise temperature and the gain of the LNA at several temperatures, from 300 K to 1.5 K. The influence of imperfect impedance matching with the temperature change is investigated. A commercial GaAs LNA in the frequency range 1–3 GHz has shown a noise temperature TN ≤ 4 K at 4.2 K and below.
4 citations
TL;DR: In this paper, the authors developed a fully coupled dynamic model of the system "antenna-transducer" and worked out some estimates of signal-to-noise ratio and the stability conditions in various experimental configurations.
Abstract: Parametric transducers, such as superconducting rf cavities, can boost the bandwidth and sensitivity of the next generation resonant antennas, thanks to a readily available technology. We have developed a fully coupled dynamic model of the system "antenna--transducer" and worked out some estimates of signal--to--noise ratio and the stability conditions in various experimental configurations. We also show the design and the prototype of a rf cavity which, together with a suitable read--out electronic, will be used as a test bench for the parametric transducer.