Andreas Freise 09.10.2007 ILIAS-GW, Tübingen

Einstein gravitational wave Telescope

Topology Identification - Plans for WP3Topology Identification - Plans for WP3

A. Freise ILIAS-GW 10/2007 Slide 2

What is the Detector Topology?

Geometry: Number of sites, detector orientation, overall size

Topology: type of each interferometer (Michelson, Sagnac, …), number and position of main interferometer optics

Configuration: interferometer operating point, mode of operation (detuned, narrow- band, …), sensing and control scheme

A. Freise ILIAS-GW 10/2007 Slide 3

NEW laser, suspensions, optical scheme, mirrors Same Infrastructure, Similar Topology

NEW laser, suspensions, optical scheme, mirrors,vibration isolators. Cryogenics. New Infrastructure, New Topology

1st generation

2nd generation

3rd generation New Topology = New Interferometry

A. Freise ILIAS-GW 10/2007 Slide 4

Topology Identification

Motivation: Why a new topology? Because we can! Third generation (3G) detectors will require a new infrastructure

The Michelson interferometer is the optimal topology for maximising the optical signal of a gravitational wave with ideal polarisation

It is, however, not necessarily the best choice for maximising the signal-to-noise ratio detecting both polarisations of a gravitational wave

A. Freise ILIAS-GW 10/2007 Slide 5

3 detectors in a triangle configuration

Early Ideas

Rüdiger, ‘85

Topology example

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Advanced Configurations

A. Freise ILIAS-GW 10/2007 Slide 9

Advanced Configurations

A. Freise ILIAS-GW 10/2007 Slide 10

WP 3 Tasks and Milestones1. Evaluation of available and developing technologies for the suppression of

quantum noise 2. Evaluation of technologies for suppressing thermal noise or generally

displacement noise3. Modelling of Interferometer Topologies. Parameterise the quantum noise

limited sensitivity of each technology 4. Modelling of Interferometer Geometries. Quantify the signal extraction and

possible noise reduction capabilities of multiple detectors in dependence of their relative geometry (co-located, co-linear, etc)

5. Study the effects of very high laser power and compute requirements with respect to circulating light power values

6. Analyse the cross-compatibilities of the technologies above 7. Trade-off analysis and system design8. Modelling of Interferometer Configuration

A. Freise ILIAS-GW 10/2007 Slide 11

WP 3 Tasks and Milestones

Evaluation of detector geometry

Evaluation of (quantum-) noise reduction schemes

Evaluation of high-power instabilities

Trade-off analysis and draft design

Final design and component specifications

A. Freise ILIAS-GW 10/2007 Slide 12

The E.T. Work Package 3Topology Identification

Commitment stated in the proposal: 149 person months

Equally large contributions from Birmingham, Glasgow, Max-Planck, CNRS

Smaller contributions from INFN, EGO This is a seed corn for a wider activity

Funding through the proposal: 3 Post-doctoral scientists for 2 years in Birmingham,

Hannover and Glasgow Coordination through Birmingham

A. Freise ILIAS-GW 10/2007 Slide 13

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A. Freise ILIAS-GW 10/2007 Slide 14

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h(f) [1/sqrt(Hz)]

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Credit: M. Punturo, G. Losurdo

A. Freise ILIAS-GW 10/2007 Slide 15

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A. Freise ILIAS-GW 10/2007 Slide 16

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