R&D VIRGO-EGO

1. R&D VIRGO-EGO N5-W3 R&D EGO-VIRGO-July 8th, 2004

2. R&D funding • EGO budget (following call for tender June 2002) • EC: STREGA • National institutions CNRS-INFN-other EGO EC N5-W3 R&D EGO-VIRGO-July 8th, 2004

3. Conventions N5-W3 R&D EGO-VIRGO-July 8th, 2004

4. (1) Adaptive optics (Naples-ILGA) • Work started at both places • Two EGO funded positions filled • First coordination meeting : 9 June • Objective of the study fixed: full design of a AO system for Virgo upgrade and lab demonstration • Main Naples tasks • Mirror technology • Control loop and algorithm • Study instrumental noise • Main ILGA tasks • Architecture (before/after MC) • Error signal extraction strategies, ITF noises • Common tasks: noise analysis, final design N5-W3 R&D EGO-VIRGO-July 8th, 2004

5. (3) Control system upgrade (LAPP-EGO) • Effective work initiated mid-march. • Some equipment still under investigation (PCI bus analyser) • Internal staff foreseen available (3.5 FTE's mobilized) • Demodulation board: new programmable compression filter developed. To be implemented in a double mezzanine on the analogue demodulation board. Printed board of prototype ordered. • New DOL and Timing interface: layout designed. Optical components selected. Generation of timing signal studied. Design of mezzanine printed board in progress. • DSP prototype developed at EGO-INFN Pisa N5-W3 R&D EGO-VIRGO-July 8th, 2004

6. Perugia (5, 6) • Improvement of Q measuring facility • Development of fully operational prototype of fused silica suspension N5-W3 R&D EGO-VIRGO-July 8th, 2004

7. (4, 6) LMA activities • Corrective coatings: • first demonstration mirror (150mm) realized • Improvement of coating Q • New samples of doped Ta2O5 realized on small coater • Improvement on Q improved by 50 % (LIGO-GEO measurements) • No degradation of optical performance • Good prospect for further improvements N5-W3 R&D EGO-VIRGO-July 8th, 2004

8. LMA MANAGEMENT COMITTEE Chapeau Mexicain Design N5-W3 R&D EGO-VIRGO-July 8th, 2004

9. LMA MANAGEMENT COMITTEE LMA MANAGEMENT COMITTEE Chapeau Mexicain 1er Essai Expérimentale Minifiz Théorique Excel N5-W3 R&D EGO-VIRGO-July 8th, 2004

10. (8) Modelling thermal noise • Firenze-Urbino • Modelling of mirrors for thermal noise analysis. • Study of each possible cause of damping (mirror substrate, polishing techniques, coatings, mirror suspension technology, targets and motors for mirror control) and investigation of frequency dependence of the quality factor. N5-W3 R&D EGO-VIRGO-July 8th, 2004

11. (9) Study of signal recycling (LAL) • Effective work initiated on 11/01/2004 • Contributions from M. Barsuglia, F. Cavalier, M. Davier, P. Hello. • EGO funded Postdoc position filled as of 15/01/04. • Collaboration with LIGO-Caltech on 40m prototype started on two lines: • development of a simulation code for signal recycling (work at Orsay and one-month visit to Caltech) • participation in the commissioning of the 40m in the SR mode (one-month visit in July). N5-W3 R&D EGO-VIRGO-July 8th, 2004

12. (10) Pisa Uni: Laser cooling of fibers • Single crystals of BaY2F8 (BaYF) doped with Tm (2%) or Yb (2.5%) grown in laboratory. • Chamber for laser cooling designed, arranged and tested for vacuum operation. • Spectroscopic investigation carried out. • Luminescence and absorption spectra for BaYF:Tm. N5-W3 R&D EGO-VIRGO-July 8th, 2004

13. (11) CO2 pulling machine (Glasgow) • Work started at beginning of March. Old lab space renovated and now fully available for the EGO R&D project. • Laser, power meter and beam dampers already received. • Team of 5 people looking after the project. Research assistant involved at 75% of his time. • On going work: • Measurement of the transmittance of silica to the CO2 laser wavelengths. • First test on the pulling and feeding technique. • First test on the self regulating mechanism. • Investigation on the three possible methods for the detection of the fibre profile. • Importat tasks that have to be carried out soon: • Conceptual design finalized. • Selection of mechanical actuators. N5-W3 R&D EGO-VIRGO-July 8th, 2004

14. (13) Wideband transducers (Padova) • Work initiated in January 2004. • Equipment necessary for the research available or on order. • Internal staff available. • EGO funded position (research assistant) expected to start in September 2004. • Design goal is a mechanical amplifier able to perform at least a gain factor of 10 on the displacement in a wide bandwidth. Displacement measured by a Fabry-Perot resonator. • Work started with a theoretical investigation by a PhD student and other researchers. Work ended in a design of a mechanical amplifier prototype together with its optical displacement transducer. • Amplifier gain evaluated with a modelling software framework (Pro/Engineer - Pro/Mechanica). Localized rigid hinges could be a source of thermoelastic noise and need further evaluation. • System setup and measurements to be carried out by PhD student and research assistant starting September 2004. N5-W3 R&D EGO-VIRGO-July 8th, 2004

15. (14)Spherical resonator (Roma TV) • Support of work on spherical detector made in collaboration with Leiden and others • Spherical detector in Leiden is progressing well: • 1 ton sphere cooled with 3 resonant transducers, • Rome and Leiden are studing the calibration procedure and coupling of the sphere modes with the transducers. • In parallel data acquisition system for the data taking is being prepared N5-W3 R&D EGO-VIRGO-July 8th, 2004

16. (15) Study of quantum noise (LKB) • Full treatment of quantum noise in interferometers. Basic numerical modules developed and tested through a full model of Fabry-Perot cavity with losses. • Experimental setup improved to reach the required sensitivity for observation of quantum effects on radiation pressure. • Stabilizing high-finesse cavity. • New mirrors received (substrates from Wave Precision, coated by LMA). • New high-finesse cavity (F>200000, few mw), suitable for cryogenic application N5-W3 R&D EGO-VIRGO-July 8th, 2004

17. Cancelling radiation pressure noise Courty, Heidmann, Pinard scheme for QND Detuned Cavity ITF cavity Short cavity L A control cavity and a detuned cavity are associated to the main interferometer Fabry-Perot cavity to reduce, through a feedback scheme the radiation pressure noise. A full evaluation of the quantum locking performance in the case of real noise sources, like seismic and thermal, has been exploited by D.Vitali et al in[iii]. N5-W3 R&D EGO-VIRGO-July 8th, 2004

18. (16) Thermal Noise at Cryogenic Temperatures (Pisa-EGO) • Cascina infrastructure modificatons initiated • Cryostat design almost completed and ordering foreseen in June • Payload design completed and procurement started • Several components ordered and some delivered (pulse tubes) • First cryogenic measurements on dummy miror before the end of the year ? N5-W3 R&D EGO-VIRGO-July 8th, 2004

19. Particular behavior of Si Crystalline Silicon N5-W3 R&D EGO-VIRGO-July 8th, 2004

20. Silicon ribbons • Silicon cantilever blades Silicon for mirrors and suspensions (From IGR-Cagnoli) • Extend the experience of GEO600 from silica to silicon monolithic suspensions N5-W3 R&D EGO-VIRGO-July 8th, 2004

21. Cryogenic test facility & Si payload N5-W3 R&D EGO-VIRGO-July 8th, 2004

22. (17) Data Analysis-(Cardiff-ILGA) • Data Analysis of Gravitational Waves from Coalescing Black Holes, • Recruitment expected before the summer, start in september N5-W3 R&D EGO-VIRGO-July 8th, 2004

23. Other conventions • (7) ILGA: ITF optimization • (6, 5) Perugia: Q measuring facility, modelling thermal noise, fused silica suspensions • (12) GEO: Diffractive optics: on hold, no candidate N5-W3 R&D EGO-VIRGO-July 8th, 2004

24. Potential R&d Items for Second Call for proposals • Laser & Injection • Study of properties of fiber optics(tubular structures) in view of their application in laser injection systems of gravitational waves ITF. • Design and prototype realization of a fiber optics laser feed for Virgo injection system. • Development of a large size and high power Faraday isolator. • Design of a second generation laser and injection system (upgrade Virgo I and Virgo II) • Optics contamination control • Development of instrumentation for in situ measurement of optics contamination • Development of processes for in situ cleaning of ITF optics (spread contamination and particles) • Development of new concepts for the assembly-integration of optics in super clean conditions. The concept may consider new vacuum chamber designs and handling procedures different from the one existing in Virgo. N5-W3 R&D EGO-VIRGO-July 8th, 2004

25. Silicon optics • Optical characterisation at cryogenic temperatures • Selection of the most adapted type of material (dopant) considering a possible use at 4, 100 and 300 K. Full characterisation of the selected variety at 300, 100, 4 degrés K. • Realization of a full size silicon demonstrator and characterisation (blank quality, high quality polishing, coating) • Test of silicon demonstrator at cryogenic temperatures (coatings, stress bending, ..) N5-W3 R&D EGO-VIRGO-July 8th, 2004

26. Potential advantages of silicon • Cristalline material (high Q ) • Polishing and coating identical to SiO2 (at 300K) • Availability in large sizes • Very interesting thermal and mechanical properties at low temperatures • Semiconductor => evacuation of charges • Problem: little experimental data (no optical data) at low temperatures • Characteristics depend of level of dopant • An extensive characterisation program is necessary (already started with Strega) N5-W3 R&D EGO-VIRGO-July 8th, 2004

27. Availability and cost • Standard diameter of wafers : • 12.7cm, 15cm, 20cm, 30cm • Present max diameter : 45cm • Cost of raw material : 1/10 of SiO2 • Polishing costs identical to SiO2 Boule 300mm, 250 kg N5-W3 R&D EGO-VIRGO-July 8th, 2004

28. Absorption @ 300 K • Example mirage effect measurement 100 ppm/cm N5-W3 R&D EGO-VIRGO-July 8th, 2004

29. Properties @ 100 K 300 K 110 K 1 ppm/cm Si dopé au phosphore N5-W3 R&D EGO-VIRGO-July 8th, 2004

30. 2 – Properties @ 100 K N5-W3 R&D EGO-VIRGO-July 8th, 2004

31. New interferometers (1) Detailed conceptual design for a second Virgo ITF sharing the existing infrastructure • Detailed concept and architecture. Preliminary cost evaluation. • Design of towers and suspensions adapted to existing infrastructure (taking account of contamination control R&D) N5-W3 R&D EGO-VIRGO-July 8th, 2004

32. New Interferometers (2) Advanced studies for a third generation cryogenic ITF • Comparative study of various architectures for a future cryogenic interferometer. • Study and conceptual design of a cryogenic suspension for second generation ITFs, • Identification of possible underground and surface sites for a future European ITF. • Conceptual design and evaluation of construction, maintenance and operation costs of a cryogenic infrastructure for a second generation ITF N5-W3 R&D EGO-VIRGO-July 8th, 2004

33. 2 possible strategies for cooled suspension COLD FINGER Cryostat Jelly fish COLD FINGER N5-W3 R&D EGO-VIRGO-July 8th, 2004

34. Fabry Perot Coupler q Litt Laser M M q 0. q in Laser Laser T=0.01 R=1 • need to store light in a cavity • also possible with gratings: R=0.99 R=0.99 R=0.99 Littrow mount: 0th & 1st order coincide  need strong grating • need weak grating total loss should be lower N5-W3 R&D EGO-VIRGO-July 8th, 2004

35. Proposed Optical Scheme GEO-HF (K. Strain) N5-W3 R&D EGO-VIRGO-July 8th, 2004