Optimization of Mechanical Impedance Matchers for Parametric Transducers in Gravitational Wave Spherical Detectors

Author(s)

Frajuca, C. ; Pires, R. ; Bortoli, F. S. ; Magalhaes, N. S. ; Marinho, R. M., Jr. ; Oliveira, F. G. ; Hannam, M ; Sutton, P ; Hild, S ; VanDenBroeck, C

• Document type: Journal article
• Source: WAKE CONFERENCE 2021; v. 363, p. 7-pg., 2012-01-01.

Abstract

A resonant-mass spherical gravitational wave detector is been built at the Physics Institute of Sao Paulo University which will be part of a detection network with a similar one that is under construction in The Netherlands. The goal of such detector is to reach a sensitivity of 10(-21) in h at frequencies close to 3200 Hz within a bandwidth of 200 Hz. Its expected sensitivity will be close to the quantum limit and for such sensitivity to be reached several parameters must be optimized One of them is the calibration of the mechanical impedance matchers, which are mechanical oscillators assembled on the sphere with the purpose of coupling the oscillations of the sphere surface to the electromechanical transducers that are used as motion sensors. This work has the goal to optimize such mechanical coupling, consequently the detector sensitivity, using a microwave parametric transducer for which an important variable is the electrical quality factor. The study involves the simulation of the oscillation of the mechanical parts of the detector with its all 17 frequency modes while checking whether these modes behave as predicted by the theory. We found that the simulation works adequately and that most of the frequency modes investigated are in good agreement with the theory about vibration quadmpole modes in spheres. Other modes did not fit so well in the theory and we comment on this in the text. (AU)

• FAPESP's process: 10/00167-4 - Optimization of mechanical impedance matchers for parametric transducers in gravitational wave spherical detectors
• Grantee: Carlos Frajuca
• Support Opportunities: Regular Research Grants
• FAPESP's process: 11/07731-5 - 9th Edoardo Amaldi Conference on Gravitational Waves
• Grantee: Nadja Simão Magalhães
• Support Opportunities: Research Grants - Meeting - Abroad