Tony Doyle [email protected] GridPP2 Proposal, BT Meeting, Imperial, 23 July 2003.
Strawman red Caltech - physics.gla.ac.uk
Transcript of Strawman red Caltech - physics.gla.ac.uk
Overview
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Task description
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Some working assumptions
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To avoid misunderstandings …
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Suspension Thermal Noise
Boosted aLIGO Quad with 1.2m long last stage and 160kg test masses.
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Suspension Thermal Noise
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Suspension R&D
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Newtonian Noise
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Used seismic from:
Newer data from LLO
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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.
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Coating Brownian noise
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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.
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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)
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Khalili cavities
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Khalili cavities
Extremely hardware intensive.
Lots of technical challenges: Thermal lensing Cavity stability Control
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Thermal lensing in K-cavity
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Waveguide mirrors
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Quantum noise
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Squeezing losses
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= 9% in total
Cavity losses in literature
Assuming losses are independent of cavity length
Speedmeter an alternative?
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Strawman Red Costs
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Overview
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For details please see document on the DCC:
https://dcc.ligo.org/cgi-bin/private/DocDB/ShowDocument?docid=78100
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