Use this URL to cite or link to this record in EThOS:
Title: Breaking the seismic wall : how to improve gravitational wave detectors at low frequency
Author: Cooper, Samuel James
Awarding Body: University of Birmingham
Current Institution: University of Birmingham
Date of Award: 2020
Availability of Full Text:
Access from EThOS:
Access from Institution:
The era of gravitational-wave astronomy was enabled by the incredible sensitivity of the LIGO and VIRGO detectors. However, they are still plagued by technical noises at frequencies below 30 Hz, driven in part by the limitations of the seismic isolation of the detector. To detect gravitational waves at low frequency, the isolation performance must be improved to reduce these technical noises. To improve the performance of seismic isolation systems, I have developed HoQI a new interferometrically sensor, that can be applied to both the isolation tables and suspensions. HoQI has a resolution a factor 1000 higher than sensors currently used in LIGO and I have quantified the level of non-linearity present in the sensor and shown this to not be a limiting factor. HoQIs impact on the performance of the seismic isolation system has also been quantified, through the use of a accurate model of an Advanced LIGO isolation platform that I have developed. Using the model I have shown that using using HoQI, the expected isolation platform motion can be reduced by a factor of 70 at 0.1 Hz and a factor of 10 at 2 Hz. I have shown that the control filters used in this model can be improved by up to 70% by designing them using particle swarm optimisation.
Supervisor: Not available Sponsor: STFC
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QC Physics