ETD system

Electronic theses and dissertations repository

 

Tesi etd-12302009-003515


Thesis type
Tesi di dottorato di ricerca
Author
BOSCHI, VALERIO
URN
etd-12302009-003515
Title
Modeling and Simulation of Seismic Attenuation Systems for Gravitational Wave Interferometers
Settore scientifico disciplinare
FIS/01
Corso di studi
FISICA APPLICATA
Commissione
tutor Prof. Passuello, Diego
relatore Prof. Sannibale, Virginio
Parole chiave
  • Seismic attenuation
  • Mechanical modeling
  • LIGO
  • Virgo
Data inizio appello
11/01/2010;
Consultabilità
completa
Riassunto analitico
In order to detect gravitational waves (GW), the displacement of the test masses has to be reduced to the challenging level of 10^(-18) m/sqrt(Hz). For second generation detectors like Advanced LIGO the requirements are even more compelling. Since the seismic noise is the dominant low frequency noise source for terrestrial GW detectors, the performance and reliability of seismic attenuation systems play a critical role. <br><br>This thesis analyzes the mechanical modeling and simulation of seismic attenuators for GW interferometers. The first part of our study concentrated on HAM-SAS, a single-stage passive mechanical isolator, proposed by the California Institute of Technology SAS group, that is designed to support the Advanced LIGO HAM vacuum chambers. Several analytical and numerical simulation techniques have been used in order to determine the performance, reliability and controllability of the system and to obtain a set of linear models that can be used for the active control of the attenuator. The second part of this work is dedicated to the pre-isolator stage of Virgo suspensions. We obtained a set of state-space representations of Virgo inverted pendulum using system identification techniques and we developed a Kalman filter, based on the linear models, that is able to estimate independently every resonance mode of the pre-isolator from open loop data.
File