The fast matched filter for gravitational-wave data analysis: Characteristics and applications

We report on the application of a matched filter to the data of two-mode resonant gravitational-wave antennas for the detection of burst signals, with reference to data obtained by direct acquisition, i.e. without going through lock-in amplifiers, sampled at relatively high speed. After a review of the basic model of resonant detectors, that includes a discussion of the signal and of the noise, we present a detailed mathematical derivation of the optimum filter matched to an input burst. We then analyze and discuss the performance of the matched filter as regards both the improvement of the signal-to-noise ratio and the observation bandwidth, also considering the adaptive realization of the filter, based on the actual spectrum of the noise as estimated from the data. The discussion that follows is centered on various aspects concerning the practical application of the matched filter as well as the loss of performance due both to uncertainties on the parameters used for building the filter and to various discretization effects, both in the time and frequency domains. Finally, we consider some experimental results obtained by applying the matched filter to the data of the Explorer detector, also providing a comparison with what we obtained by applying an optimum filter to data processed by lock-in amplifiers, sampled at lower speed

MiniGRAIL progress report 2004

The MiniGRAIL detector was improved. The sphere was replaced by a slightly larger one, having a diameter of 68 cm (instead of 65 cm), reducing the resonant frequency by about 200 Hz to around 2.9 kHz. The last four masses of the attenuation system were machined to increase their resonant frequency and improve the attenuation around the resonant frequency of the sphere. In the new sphere, six holes were machined on the TIGA positions for easy mounting of the transducers. During the last cryogenic run, two capacitive transducers and a calibrator were mounted on the sphere. The first transducer was coupled to a double-stage SQUID amplifier having a commercial quantum design SQUID as a first stage and a DROS as a second stage. The second transducer was read by a single-stage quantum design SQUID. During the cryogenic run, the sphere was cooled down to 4 K. The two-stage SQUID had a flux noise of about 1.6 μ0 Hz−1/2. The detector was calibrated and the sensitivity curve of MiniGRAIL was determined

Detection of impulsive, monochromatic and stochastic gravitational waves with resonant antennas

Consiglio Nazionale delle Ricerche (CNR). Biblioteca Centrale / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

MiniGRAIL progress report 2004

The MiniGRAIL detector was improved. The sphere was replaced by a slightly larger one, having a diameter of 68 cm (instead of 65 cm), reducing the resonant frequency by about 200 Hz to around 2.9 kHz. The last four masses of the attenuation system were machined to increase their resonant frequency and improve the attenuation around the resonant frequency of the sphere. In the new sphere, six holes were machined on the TIGA positions for easy mounting of the transducers. During the last cryogenic run, two capacitive transducers and a calibrator were mounted on the sphere. The first transducer was coupled to a double-stage SQUID amplifier having a commercial quantum design SQUID as a first stage and a DROS as a second stage. The second transducer was read by a single-stage quantum design SQUID. During the cryogenic run, the sphere was cooled down to 4 K. The two-stage SQUID had a flux noise of about 1.6 μ0 Hz−1/2. The detector was calibrated and the sensitivity curve of MiniGRAIL was determined