Virgo+: Medium-Scale Improvements for Advanced Virgo Sensitivity Enhancement

1. Virgo+ & Advanced Virgo B. Mours With material from G. Losurdo, M. Punturo, A. Viceré and others ILIAS-WG3 Frascati

2. Virgo+ • Virgo+ concept: • Medium scale improvementscompatibles with the main Virgo subsystems • “Plug and play” • Same optical layout • Could be incremental • Limited shutdown • Limited commissioning time • Four packages have been identified: • Monolithic payloads with fused silica suspensions • “New” laser with limited power increase (20W → 50W) • Mirror thermal compensation • Electronics and control system upgrades • Installation target: beginning of 2008 ILIAS-WG3 Frascati

3. Depending on thermal noise model Newtonian noise Virgo+ Sensitivity (a) fbulk= 10-7 [Virgo design model] (b) fbulk= 10-9[Penn et al. 2005] ILIAS-WG3 Frascati

4. New loss angle evaluation LIGO Virgo Region of interest for thermal noise in adv Virgo/LIGO ILIAS-WG3 Frascati

5. Virgo+ Astrophysical impact Inspiral Range (Mpc): averaged (optimal orientation ) ILIAS-WG3 Frascati

6. Virgo+ planning • Need to reach the Virgo design sensitivity first • 2007: We expect to spend more than 50% of time taking data • Shutdown for Virgo+ installation • Start: from fall 2007 to the beginning of 2008. • End (back to vacuum) : about 6 months later. • This installation time could be reduced if new clean rooms are installed. • The installation will be followed by recommissioning • Back to science mode operation around the end of 2008. • WP package planning remarks (From November EGO council mtg): • Laser: • Need to order some components ASAP (Fiber laser and laser amplifier) • Monolithic suspension: • R&D already going on but the engineering part is probably the longest activity for Virgo+. • The mirror production is a long operation: Need to order the “blanks” ASAP • Electronic upgrade • R&D already going on. • Thermal compensation system • Not on the critical path. ILIAS-WG3 Frascati

7. Virgo+ Budget NOVEMBER 2005 Estimate • Remarks: • For laser and monolithic suspension: summary of WP numbers (recent numbers) • For the electronic and thermal compensation: rough estimate. • Some items are part of the regular EGO budget as Virgo maintenance cost. • The cost of the needed infrastructure (new clean rooms) is not included • The 2007 budget may need some adjustments when details will be known. • Seems to fit in the EGO Budget if Virgo+ is a priority ILIAS-WG3 Frascati

8. Advanced Virgo ILIAS-WG3 Frascati

9. Advanced Virgo • Target sensitivity improvement: • One order of magnitude compared to initial Virgo • Time scale: Shutdown around 2011 • To be compatible with Advanced LIGO • Bigger changes compared to Virgo+: • New beam topology: • Flat beam? Change the beam waist? Signal recycling?? • Progress on internal thermal noise: • Material? Coating? Monolithic suspension? • Newtonian noise subtraction? • … • But Smaller Changes than Advanced LIGO • keep the seismic isolation. ILIAS-WG3 Frascati

10. Advanced Virgo Sensitivity? • Not yet defined! • Task of the working group • Target: Virgo/10 • Some possibilities: ILIAS-WG3 Frascati

11. Advanced Virgo Organisation • 4 Working groups set up (coordinators appointed) • Low thermal noise suspensions and optics (M.Punturo, G.Losurdo) • High power laser and input optics (N.Man, P.La Penna) • Optical configuration (A.Freise, P.Hello) • (Including thermal compensation, flat beams, locking issues and signal recycling) • Electronics and controls. (A.Masserot, A.Gennai) • Goal of the working groups: • Define the base line for Advanced Virgo • To be included in the Advanced Virgo white paper? • Define the work packages • Estimate the cost and planning • The budget request to be issued end of 2007 (?) • GEO-Virgo MOU: • To be signed soon? ILIAS-WG3 Frascati