Advanced VIRGO

WG1: Status

14.06.2007 VIRGO, Cascina

Andreas Freise

University of Birmingham

14.06.2007 A. Freise2

Group Status Organisation, Resources Man power, schedule

Group Status Organisation, Resources Man power, schedule

Overview

Technical Status Expected outputs Status of the R+D Some 'cost' estimates

Technical Status Expected outputs Status of the R+D Some 'cost' estimates

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Expected Output (1)

Parameter for core optics (March 2006) parametrised formula for SR response (or sensitivity) mirror coating specification beam shape and position throughout the IFO substrate size and geometry

(i.e. the constrains on it from ray tracing) number and position of readout ports

(i.e. the impact on the outer geometry of the vacuum system and around it)

basic parameter set that can be used for various simulation input files

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Advanced VIRGO Sensitivity

Optical readout noise: simple analytic computations (white paper), simulation codes are almost ready

Thermal noise: beam shape and size, under investigation

Control noise: no idea (no locking scheme,…)

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Advanced VIRGO Test Layout

VIRGO note VIR-NOT-EGO-1390-330

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Advanced VIRGO Simulations

Finesse: input file is available and is being used (Andreas, Maddalena, …), code currently being extended to include radiation pressure effects

New software by Courty and LeBars: should be available soon

Siesta: development should re-start now Various LIGO simulations could be adopted

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Advanced VIRGO Working Area

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Expected Output (2)

Evaluate benefits and costs for the different options

Signal Recycling (RSE) Flat beams, higher order LG modes

DC Readout Non-degenerate recycling cavities Wedges/no wedges in optical substrates

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Cost Evaluation

Larger apertures (tubes, flanges, baffles, …)

New modulation-demodulation scheme (optics, electronics)

New input/output optics (telescopes, mode cleaners, benches,…)

High quality optics in output ports

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Flat Beams

Special mirror substrates and coatings for core optics

Many special auxiliary optics Different suspension controls Complex input/ouput optics

for all ports (inlcuding pick-off beams)

See talks by J.Y. Vinet, M. Laval !

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Higher Order LG Modes

LG mode generation and mode cleaning

Problems in main interferometer and read-out ports not yet clear (there arenone??)

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Signal Recycling

Additional suspension, additional core mirror

Probably additional modulation-demodulation frequency (modulator, electronics)

Requires a more advanced lock-acquisition scheme

More complex calibration and reconstruction process

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Non-Degenerate Recycling Cavities

New optics in vacuum system (tanks, tubes, suspensions, optics, …??) Might be required anyway, depends on input optics and requirements.

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DC Readout

More advanced output mode-cleaner (high finesse, low-noise)

Better laser power stabilisation

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Summary

Work underway towards a parameter set for the core optics

Currently based on a simple extension of VIRGO with Signal Recycling

Trade-off between this and other options is difficult, more R+D needed

Cost evaluation started but also lacks more accurate input data

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… end of part 1.

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Group Organisation

The group WG1 is currently a loose meeting of interested people

Several independent R+D activities are now linked together through WG1

New R+D activities are initiated by WG1

No-one is yet committed to any of the priority tasks

Some people seem more interested in R+D for 3rd generation detectors than in 'Advanced' VIRGO

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Resources

All information is available in the EGO-VIRGO working area

Simulation codes must be made available (and advertised better)

Meetings and discussions not very regular nor frequent, mostly due to the lack of progress (see next slide)

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Man Power

VIRGO and VIRGO+ have priorityBut: we have no direct link to discussions about either!

Most people hope to become more available now that VSR1 started

Birmingham should hire a 100% dedicated post-doc anytime now

No 'young' people with a long term perspective are active in this group

Time scales are very difficult without a more dedicated effort (see Rai's comment during the LSC meeting)

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Length Sensing and Control

No volunteers for this topic yet This will limit the progress from now

on This should be the most interesting

topic: use what you learned from the design and commissioning of VIRGO!

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Summary

WG1 has provided a good starting point for the collaboration

We probably need to link better with VIRGO and VIRGO+ activities

The R+D effort towards Advanced VIRGO is low compared to similar projects, thus the working group will be required to make decisions without having the data from R+D projects

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… end.