R&D activities in Florence

1. R&D activities in Florence Geppo Cagnoli INFN and U. of Glasgow WG2 & WG3 Meeting – 27th Apr. 2006 - Firenze

2. Firenze/Urbino group • 6 Staff members working on STREGA: • Flavio Vetrano Francesco Marin • Filippo Martelli • Giovanni Losurdo • Francesco Piergiovanni • Geppo Cagnoli • Supporting staff members: • Andrea Vicere’ • Gianluca Guidi • 2 Post docs: Enrico Campagna Francesco Marino • 2 PhD Students: Matteo Lorenzini Elisabetta Cesarini WG2/3 Meeting - GWA - Firenze

3. Firenze and Urbino Urbino WG2/3 Meeting - GWA - Firenze

4. Activities on thermal noise • Modelling of thermal noise for Virgo optics and suspensions (funded by EGO) • Measurements on crystalline silicon fibres (CRYSTAL collaboration, funded by INFN ) • Study of new materials for 3rd generation interferometric GW detectors (JRA3-STREGA collaboration) WG2/3 Meeting - GWA - Firenze

5. Silicon fibres measurements setup X-Y shadow sensor photodiodes Finite element analysis exciter Fibre is clampedwith 2 Al blocks Vacuum chamber P = 10-5/10-6 mbar Fibre profile measurements setup WG2/3 Meeting - GWA - Firenze

6. Achievements • Profiling and modelling WG2/3 Meeting - GWA - Firenze

7. Achievements cont. • Measurements L=111.5 mm average diameter 242mm L=308 mm average diameter 574mm WG2/3 Meeting - GWA - Firenze

8. Open points • Excess losses with 1.5mm diameter fibre thermoelastic WG2/3 Meeting - GWA - Firenze

9. Open points cont. • Like in Glasgow we used a piezo for sensing and for exciting the structure Fibre Structure WG2/3 Meeting - GWA - Firenze

10. Open points cont. orthogonal parallel • Excess losses are higher for the “orthogonal” than for “parallel” modes (!!) Force and torque on the clamp (G.Cagnoli, F. Martelli, F. Piergiovanni) WG2/3 Meeting - GWA - Firenze

11. Cryogenic facility Thermal expansion coefficient Thermal conductivity Q measurements (possible, but our set up is not optimized for this) Study of the properties of materials suitable for 3rd generation interferometric GW detectors To be performed inside the JRA3-STREGA collaboration Measurements concern Crystalline Silicon Samples WG2/3 Meeting - GWA - Firenze

12. The cryostat 30 cm Inner cold shield Outer cold shield Optical windows A.S. Scientific cryostat Experimental volume: about 14 dm3 Vacuum chamber Outer tank Liquid N2 Inner tank Liquid He Optical windows WG2/3 Meeting - GWA - Firenze Experimental chamber

13. Thermal conductivity measurement INSULATOR BOX HEATER CLAMP THERMOMETERS SAMPLE SAMPLE HEATER COPPER BOX WG2/3 Meeting - GWA - Firenze

14. Measurement of the power loss CLAMP • We are measuring the heat lost by wire conduction and radiation 1mW of heating power INSULATOR BOX HEATER THERMOMETERS SAMPLE SAMPLE HEATER COPPER BOX At room temperature we have measured: Heat Capacity of the sample 4.2 J/K Heat Conductivity 3.7 mW/K WG2/3 Meeting - GWA - Firenze

15. Thermal expansion measurement facility WG2/3 Meeting - GWA - Firenze

16. Measuring cavity Very soft elastic blades Sample Laser Mobile clamp Mirrors Fixed clamp WG2/3 Meeting - GWA - Firenze

17. The reference cavity Elastic Cu/Be blades Reference material: zerodur Mirror 1 K Piezo actuator 1 h Vacuum chamber hosting reference cavity Heating wires for RC temperature control Result of the temperature stabilization(Matteo Lorenzini) WG2/3 Meeting - GWA - Firenze

18. Photothermal effect facility Small spot size results Low frequency: size effect High frequency: coating effect WG2/3 Meeting - GWA - Firenze

19. Conclusion • First measurement of thermal conductivity expected soon • The reference cavity for thermal expansion measurements is being assembled • Photothermal facility is working successfully • We are looking forward to show you our labs tomorrow afternoon WG2/3 Meeting - GWA - Firenze