Comparison of advanced gravitational-wave detectors

We compare two advanced designs for gravitational-wave antennas in terms of their ability to detect two possible gravitational wave sources. Spherical, resonant mass antennas and interferometers incorporating resonant sideband extraction (RSE) were modeled using experimentally measurable parameters. The signal-to-noise ratio of each detector for a binary neutron star system and a rapidly rotating stellar core were calculated. For a range of plausible parameters we found that the advanced LIGO interferometer incorporating RSE gave higher signal-to-noise ratios than a spherical detector resonant at the same frequency for both sources. Spheres were found to be sensitive to these sources at distances beyond our galaxy. Interferometers were sensitive to these sources at far enough distances that several events per year would be expected

Workshop on gravitational waves

In this article we summarise the proceedings of the Workshop on Gravitational Waves held during ICGC-95. In the first part we present the discussions on 3PN calculations (L. Blanchet, P. Jaranowski), black hole perturbation theory (M. Sasaki, J. Pullin), numerical relativity (E. Seidel), data analysis (B.S. Sathyaprakash), detection of gravitational waves from pulsars (S. Dhurandhar), and the limit on rotation of relativistic stars (J. Friedman). In the second part we briefly discuss the contributed papers which were mainly on detectors and detection techniques of gravitational waves.Comment: 18 pages, kluwer.sty, no figure

Microwave apparatus for gravitational waves observation

In this report the theoretical and experimental activities for the development of superconducting microwave cavities for the detection of gravitational waves are presented.Comment: 42 pages, 28 figure

Physics, Astrophysics and Cosmology with Gravitational Waves

Gravitational wave detectors are already operating at interesting sensitivity levels, and they have an upgrade path that should result in secure detections by 2014. We review the physics of gravitational waves, how they interact with detectors (bars and interferometers), and how these detectors operate. We study the most likely sources of gravitational waves and review the data analysis methods that are used to extract their signals from detector noise. Then we consider the consequences of gravitational wave detections and observations for physics, astrophysics, and cosmology.Comment: 137 pages, 16 figures, Published version <http://www.livingreviews.org/lrr-2009-2

Advanced Gravitational Radiation Transducers With Small Mass and Ultra-Low Temperature SQUIDs.

The transducer and SQUID are two major components for a resonant-mass gravitational wave antenna. They must always have high sensitivity and low noise. In this work, a two-mode superconducting inductive transducer for a three-mode gravitational wave bar antenna is designed. The construction and tests of small mass resonators that form the transducer are described. The experiments and test results of commercial dc SQUIDs at ultra-low temperature are discussed in detail. Special problems arise when SQUIDs are tested at ultra-low temperature in vacuum. We address the problems and provide proper solutions. Our experiments show that the dc SQUID made by Quantum Design operates well at temperatures as low as 50 mK. We find that the SQUID has an energy resolution of 2600 $\hbar$. The SQUID\u27s noise did not decrease with temperature as was expected. The possible reasons for this are discussed. The two-mode inductive transducer is designed based on a noise analysis of the complete three-mode system. A small mass of 8-9 grams is chosen for the transducer\u27s diaphragm. The geometry of both the small mass resonator and the intermediate resonator that form the transducer is designed with the aid of finite element analysis. One of two aluminum prototype resonators reached a mechanical Q of 8.3\times10\sp6 at 4.2 K. Among the three fabricated niobium resonators, one achieved mechanical Qs of 2.4\times10\sp7 at 4.2 K and 3.0\times10\sp7 at around 7 K. Another one with arms cut by Electrical Discharge Machining has reached mechanical Qs of 7.4\times10\sp6 at 4.2 K and 1.3\times10\sp7 at 8.3 K. Its electrical Q has been found to be 5.0\times10\sp5 with an electromechanical coupling efficiency of 15%. This is equivalent to an average $\beta$Q of 4.7\times10\sp5. This resonator is suitable for use in working transducers. An effective annealing procedure was discovered and applied in the fabrication process of these niobium resonators

Hybrid Evolutionary Computing Assisted Irregular-Shaped Patch Antenna Design for Wide Band Applications

A novel optimization concept for modeling irregular-shaped patch antenna with high bandwidth and efficient radiation attributes is proposed in this paper, along with the ability to accomplish the design at a reduced computational and cost burden. A revolutionary computing perception is established with Gravitational Search Algorithm (GSA) and Quantum Based Delta Particle Swarm Optimization (QPSO), now known as GSA-QPSO. The suggested model employed the GSA-QPSO algorithm strategically interfaced with a high-frequency structure simulator (HFSS) software through a Microsoft Visual Basic script to enhance irregular-shaped antenna design while maintaining wide bandwidth with suitable radiation efficiency over the target bandwidth region. The optimally designed microstrip patch antenna is fabricated on an FR-4 substrate with a surface area of 30×30×1.6 mm 3 . The evaluated outcome shows 96 % supreme radiation efficacy at 2.4 GHz whereas overall effectiveness is above 84% over the entire frequency range, with a nearly omnidirectional radiation pattern. In terms of impedance bandwidth, the suggested antenna offers 126.6 % over the operational frequency range from 2.34 GHz to 10.44 GHz. Fabrication and measurement results are also used to validate the simulated results. It exhibits the proficiency of the offered antenna design to be used for real-world wideband (WB) communication drives

Structural interaction with control systems

A monograph which assesses the state of the art of space vehicle design and development is presented. The monograph presents criteria and recommended practices for determining the structural data and a mathematical structural model of the vehicle needed for accurate prediction of structure and control-system interaction; for design to minimize undesirable interactions between the structure and the control system; and for determining techniques to achieve the maximum desirable interactions and associated structural design benefits. All space vehicles are treated, including launch vehicles, spacecraft, and entry vehicles. Important structural characteristics which affect the structural model used for structural and control-system interaction analysis are given