1. Advanced VIRGO WG1: Status 14.06.2007 VIRGO, Cascina Andreas Freise University of Birmingham

2. 14.06.2007A. 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

3. 14.06.2007A. Freise3 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

4. 14.06.2007A. Freise4 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,…)

5. 14.06.2007A. Freise5 Advanced VIRGO Test Layout VIRGO note VIR-NOT-EGO-1390-330

6. 14.06.2007A. Freise6 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

7. 14.06.2007A. Freise7

8. 14.06.2007A. Freise8 Advanced VIRGO Working Area

9. 14.06.2007A. Freise9 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

10. 14.06.2007A. Freise10 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

11. 14.06.2007A. Freise11 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 !

12. 14.06.2007A. Freise12 Higher Order LG Modes  LG mode generation and mode cleaning  Problems in main interferometer and read-out ports not yet clear (there are none??)

13. 14.06.2007A. Freise13 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

14. 14.06.2007A. Freise14 Non-Degenerate Recycling Cavities  New optics in vacuum system (tanks, tubes, suspensions, optics, …??)  Might be required anyway, depends on input optics and requirements.

15. 14.06.2007A. Freise15 DC Readout  More advanced output mode- cleaner (high finesse, low-noise)  Better laser power stabilisation

16. 14.06.2007A. Freise16 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

17. 14.06.2007A. Freise17 … end of part 1.

18. 14.06.2007A. Freise18 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

19. 14.06.2007A. Freise19 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)

20. 14.06.2007A. Freise20 Man Power  VIRGO and VIRGO+ have priority But: 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)

21. 14.06.2007A. Freise21 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!

22. 14.06.2007A. Freise22 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

23. 14.06.2007A. Freise23 … end.