strawman red caltech - physics.gla.ac.uk
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Overview
Stefan Hild Slide 2 Strawman Caltech, Jan 2012
Task description
Stefan Hild Slide 3 Strawman Caltech, Jan 2012
Some working assumptions
Stefan Hild Slide 4 Strawman Caltech, Jan 2012
To avoid misunderstandings …
Stefan Hild Slide 5 Strawman Caltech, Jan 2012
Suspension Thermal Noise
Boosted aLIGO Quad with 1.2m long last stage and 160kg test masses.
Stefan Hild Slide 6 Strawman Caltech, Jan 2012
Suspension Thermal Noise
Stefan Hild Slide 7 Strawman Caltech, Jan 2012
Suspension R&D
Stefan Hild Slide 8 Strawman Caltech, Jan 2012
Newtonian Noise
Stefan Hild Slide 9 Strawman Caltech, Jan 2012
Used seismic from:
Newer data from LLO
Stefan Hild Slide 10 Strawman Caltech, Jan 2012
New data from LLO seem to suggest that Strawman red underestimates the GGN level by about a factor 2. Work in progress!
Seismic barrages
2D finite-difference time-domain simulations for barrages of 40x40m.
Attenuation of seismic by about a factor 2.
Stefan Hild Slide 11 Strawman Caltech, Jan 2012
Coating Brownian noise
Stefan Hild Slide 12 Strawman Caltech, Jan 2012
Increasing the beam size
Assume an increase of beam size by a factor 1.6.
Keep aspect ratio of test masses as it is => 160kg.
Stefan Hild Slide 13 Strawman Caltech, Jan 2012
Optical coatings with reduced thermal noise
Continued improvement of tantala coatings. Loss related to local atomic structure of material
High-temperature annealing of coatings. Heat treatment in the range of 500-1000 degrees centigrade
Amorphous silicon as a high-index coating material n=3.5 => quarter-wave layer is thinner. In addition need fewer layers. Potential improvement = 4.6 Requires change of laser wavelength
Crysatalline coatings (AlGaAs)
Stefan Hild Slide 14 Strawman Caltech, Jan 2012
Khalili cavities
Stefan Hild Slide 15 Strawman Caltech, Jan 2012
Khalili cavities
Extremely hardware intensive.
Lots of technical challenges: Thermal lensing Cavity stability Control
Stefan Hild Slide 16 Strawman Caltech, Jan 2012
Thermal lensing in K-cavity
Stefan Hild Slide 17 Strawman Caltech, Jan 2012
Waveguide mirrors
Stefan Hild Slide 18 Strawman Caltech, Jan 2012
Quantum noise
Stefan Hild Slide 19 Strawman Caltech, Jan 2012
Squeezing losses
Stefan Hild Slide 20 Strawman Caltech, Jan 2012
= 9% in total
Cavity losses in literature
Assuming losses are independent of cavity length
Speedmeter an alternative?
Stefan Hild Slide 21 Strawman Caltech, Jan 2012
Strawman Red Costs
Stefan Hild Slide 22 Strawman Caltech, Jan 2012
Stefan Hild Slide 23 Strawman Caltech, Jan 2012
Stefan Hild Slide 24 Strawman Caltech, Jan 2012
Overview
Stefan Hild Slide 25 Strawman Caltech, Jan 2012
For details please see document on the DCC:
https://dcc.ligo.org/cgi-bin/private/DocDB/ShowDocument?docid=78100
Stefan Hild Slide 26 Strawman Caltech, Jan 2012
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