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Jo van den Brand e-mail: jo@nikhef.nl

Design study for 3rd generation interferometers Work Package 1 Site identification and infrastructure. Jo van den Brand e-mail: jo@nikhef.nl. T ü bingen, October 9, 2007. Site identification issues: science. R ü diger, ‘85. Improved sensitivity compared to LIGO and Virgo

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Jo van den Brand e-mail: jo@nikhef.nl

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  1. Design study for 3rd generation interferometersWork Package 1Site identification and infrastructure Jo van den Brand e-mail: jo@nikhef.nl Tübingen, October 9, 2007

  2. Site identification issues: science Rüdiger, ‘85 • Improved sensitivity compared to LIGO and Virgo • Sensitivity below 10-24 m/sqrt(Hz) • Ultra-low frequency cut-off • Underground site • Multiple interferometers • 3 interferometers; triangular configuration? • 10 km long arms • 2 polarization + redundancy • Design study part of FP7 & ILIAS

  3. Courtesy: G.Cella Surface waves Compression waves Seismic displacement noise • Seismic displacement noise • Driven by wind, volcanic, seismic activity • Ocean tides, cultural noise (e.g. humans, cars) • Ground-water variations • Complicates operation of ITF, certainly in future designs with high finesse cavities • Active control systems, seismometers feedback to mirrors • Underground • Surface and compression waves • Die exponentially with depth

  4. Experience: CLIO – Prototype for LCGT

  5. Experience: underground interferometers • LISM: 20 m Fabry-Perot interferometer, R&D for LCGT, moved from Mitaka (ground based) to Kamioka (underground) • Seismic noise much lower: • Operation becomes easier • 102 overall gain • 103at 4 Hz

  6. Gravity gradient noise • Gravity gradient noise • Time varying contributions to Newtonian background driven by seismic compression waves, ground-water variations, slow-gravity drifts, weather, cultural noise • Determines low-frequency cut-off • Cannot be shielded against • Counter measures • Network of seismometers and development of data correction algorithms • Analytical studies: G. Cella • Numerical studies Figure: M.Lorenzini

  7. NN reduction in caverns Cavern radius [m] 102 less seismic noise x 104 geometrical reduction 106 overall reduction (far from surface) Spherical Cavern G.Cella Reduction factor (Compression waves not included) NN reduction of 104 @5 Hz with a 20 m radius cave 5 Hz 10 Hz 20 Hz 40 Hz Compression waves: R. De Salvo

  8. Ultra soft vibration isolation: sensitivity at low frequency Upper experimental hall 50-100 m tower to accommodate long suspension for low frequency goal Ellipsoidal/spherical cave for newtonian noise reduction Credit: R.De Salvo 10 km tunnel Working group 2

  9. Other criteria • Site selection and evaluation • Site availability and acquisition risk • Acquire land rights in reasonable time frame • Scientific suitability • Various noise sources • Construction suitability • Geological conditions (topography, hydrology) • Environmental considerations • Legal issues • Earthwork costs (local soil waste, labor costs) • Operations suitability • Supporting technical infrastructure (local University support) • Nearby communities (travel time, schools, etc.) • Operation costs (power, utilities, etc.) • Risks from environmental sources or future development • Future developments (noise sources) • Earthquakes, etc.

  10. ILC, NLC, Tesla, VLHC, Muon Source – Site requirements

  11. Dusel in USA: NSF – July 10, 2007 – 15 M$ study

  12. Site identification • Geological issues • Collaborate with earth science community • Roma 3, VU Amsterdam • Perform seismic measurements • Salt mines, granite • Geotechnical site reports • Existing mines / tunnels • Horizontal site access • Cost issues • Excavation costs • Equipment costs • Crushed rock disposal • Infrastructure • Vacuum, cryogenics Gran Sasso Salt mines

  13. Logistics for FP7 Define detailed strategy in first WP1 meeting

  14. FP7 foreseen resources • 44 kEuro travel • 1 postdoc for 3 years, 1 postdoc for 2 years • 30 kEuro for external work

  15. Contact me: jo@nikhef.nl Summary • Site selection for 3rd generation ITF • Underground site • Seismic activity, gravity gradient noise • Numerous technical issues • Collaborative design study • Interest expressed by • Caltech - LIGO • CNRS - Annecy • EGO • Florence • GEO600 • Gran Sasso • Nikhef / VU • Pisa • Roma 1, 3 • Start regular meetings (as soon as EC formalities are completed) • First meeting at Gran Sasso (E. Coccia)(Underground Lab. Community)

  16. Gravity gradient noise • Gravity gradient noise • Time varying contributions to Newtonian background driven by seismic compression waves, ground-water variations, slow-gravity drifts, weather, cultural noise • Determines low-frequency cut-off • Cannot be shielded against • Counter measures • Network of seismometers and development of data correction algorithms • Analytical studies: G. Cella • Numerical studies Figure: M.Lorenzini

  17. Possible strategy • Join the N2 network `Deep Underground Science Laboratories: DLnet (0.8 MEuro)’.

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