We solve algebraically the equations of motion for a spherical antenna coupled to an arbitrary nu... more We solve algebraically the equations of motion for a spherical antenna coupled to an arbitrary number of small resonators, free to move ra-dially, and investigate the conditions under which damping forces can be neglected in the system. We show that in order that the antenna's ...
In this article, we describe the vibrational isolation system, the thermal link and the transduce... more In this article, we describe the vibrational isolation system, the thermal link and the transducer mechanical structure, for the Schenberg resonant gravitational wave detector, which has been conceived modeled and analyzed using the finite element method. The dynamical equations corresponding to the structure have been solved using the MSC/NASTRAN software. In order to study the overall system behavior and the noise influence on it, we have carried out the analysis considering simultaneously all mechanical systems: vibrational isolation, thermal linking (between the dilution refrigerator and the suspension), and transducer-resonant mass mechanical coupling. Our calculation shows that a 300 dB attenuation level could be obtained.
Cavidades reentrantes de nióbio vêm sendo utilizadas pelo grupo Australiano nos transdutores elet... more Cavidades reentrantes de nióbio vêm sendo utilizadas pelo grupo Australiano nos transdutores eletromecânicos paramétricos do detector de ondas gravitacionais Niobè. Esses transdutores paramétricos são ativados por um sinal AC na faixa de microondas (banda X), que é modulado pelo sinal mecânico da vibração da antena esférica, com a variação de um parâmetro, que, no caso, é a capacitância da cavidade.
We present a data analysis method for searching monochromatic signals in temporal series. With th... more We present a data analysis method for searching monochromatic signals in temporal series. With this method it is possible to estimate the power spectrum by using averaged modified periodograms which reinforce the presence of peaks due to monochromatic signals. In particular we use ALLEGRO's gravitational wave data for the year 1999 taking into account the effect due to the orbital motion of the Earth. We tested the method injecting a simulated signal in real data and we were able to detect it. Then we seeked for candidate signals within the noise but nothing was found. The method showed useful for applications in the search for continuous gravitational waves.
Abstract: The first phase of the Brazilian Graviton Project, which is the construction and operat... more Abstract: The first phase of the Brazilian Graviton Project, which is the construction and operation of the gravitational wave detector Mario Schenberg at the Physics Institute of the University of São Paulo, has been recently approved by FAPESP (the Science Foundation ...
The present work quantifies the dependence of the tunable frequency range on the gap spacing betw... more The present work quantifies the dependence of the tunable frequency range on the gap spacing between the end of the conical post and the cavity top plate in reentrant 1.0 GHz klystron cavities. Fabricated from aluminum, the cavities tested are 80 mm in diameter with a top plate 1 mm thick. Experiments performed on such cavities have shown tuning coefficients (change in resonant frequency due to variation of the capacitive gap) as high as 40.0 MHz/μm, thereby demonstrating the capability of reentrant cavities as electromechanical transducers in resonant mass gravitational wave antennas. For cavity-based transducers ten times as small as the cavities tested here, this result translates into a tuning coefficient 100 times higher.
We solve algebraically the equations of motion for a spherical antenna coupled to an arbitrary nu... more We solve algebraically the equations of motion for a spherical antenna coupled to an arbitrary number of small resonators, free to move ra-dially, and investigate the conditions under which damping forces can be neglected in the system. We show that in order that the antenna's ...
In this article, we describe the vibrational isolation system, the thermal link and the transduce... more In this article, we describe the vibrational isolation system, the thermal link and the transducer mechanical structure, for the Schenberg resonant gravitational wave detector, which has been conceived modeled and analyzed using the finite element method. The dynamical equations corresponding to the structure have been solved using the MSC/NASTRAN software. In order to study the overall system behavior and the noise influence on it, we have carried out the analysis considering simultaneously all mechanical systems: vibrational isolation, thermal linking (between the dilution refrigerator and the suspension), and transducer-resonant mass mechanical coupling. Our calculation shows that a 300 dB attenuation level could be obtained.
Cavidades reentrantes de nióbio vêm sendo utilizadas pelo grupo Australiano nos transdutores elet... more Cavidades reentrantes de nióbio vêm sendo utilizadas pelo grupo Australiano nos transdutores eletromecânicos paramétricos do detector de ondas gravitacionais Niobè. Esses transdutores paramétricos são ativados por um sinal AC na faixa de microondas (banda X), que é modulado pelo sinal mecânico da vibração da antena esférica, com a variação de um parâmetro, que, no caso, é a capacitância da cavidade.
We present a data analysis method for searching monochromatic signals in temporal series. With th... more We present a data analysis method for searching monochromatic signals in temporal series. With this method it is possible to estimate the power spectrum by using averaged modified periodograms which reinforce the presence of peaks due to monochromatic signals. In particular we use ALLEGRO's gravitational wave data for the year 1999 taking into account the effect due to the orbital motion of the Earth. We tested the method injecting a simulated signal in real data and we were able to detect it. Then we seeked for candidate signals within the noise but nothing was found. The method showed useful for applications in the search for continuous gravitational waves.
Abstract: The first phase of the Brazilian Graviton Project, which is the construction and operat... more Abstract: The first phase of the Brazilian Graviton Project, which is the construction and operation of the gravitational wave detector Mario Schenberg at the Physics Institute of the University of São Paulo, has been recently approved by FAPESP (the Science Foundation ...
The present work quantifies the dependence of the tunable frequency range on the gap spacing betw... more The present work quantifies the dependence of the tunable frequency range on the gap spacing between the end of the conical post and the cavity top plate in reentrant 1.0 GHz klystron cavities. Fabricated from aluminum, the cavities tested are 80 mm in diameter with a top plate 1 mm thick. Experiments performed on such cavities have shown tuning coefficients (change in resonant frequency due to variation of the capacitive gap) as high as 40.0 MHz/μm, thereby demonstrating the capability of reentrant cavities as electromechanical transducers in resonant mass gravitational wave antennas. For cavity-based transducers ten times as small as the cavities tested here, this result translates into a tuning coefficient 100 times higher.
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Papers by Odylio Aguiar