1. WP2-WP3 Joint Meeting - Jena - March 1-3, 2010

2. Several different mechanisms contribute to the thermal noise of the mirror: Brownian (BR)(substrate, coating) (T,  ) Thermoelastic (TE) (substrate) (Thermal props) Thermorefractive (TR) dn/dT (substrate) Thermo-optic new correlated model (TR-TE) (coating) The coating brownian noise dominates over the other thermal sources

3. 3 WP2-WP3 Joint Meeting - Jena - March 1-3, 2010 *Amaldi 8, New York, June 2009 and MG12, Paris, July 2009, proceedings

4. 4 To reach a temperature of 10K with a power of 3W on the mirror we need a silicon suspension wire with a diameter of 8 mm; The temperature of the marionette stage can be 5 K or 2K depending on which kind of refrigeration system is used WP2-WP3 Joint Meeting - Jena - March 1-3, 2010

5. Modes: pendulum 0.28 Hz, 0.36 Hz, 0.50Hz vertical 0.4 Hz (blades), 23 Hz, 62 Hz violins15.8 Hz, 31.6 Hz, 63.2 Hz, 126.4 Hz, … WP2-WP3 Joint Meeting - Jena - March 1-3, 2010 M1M1 M2M2 M3M3

6. 6 Wires and substrate Properties

7. Coating Properties (from Janyce Franc transparencies) SiO 2 thin filmTi:Ta 2 O 5 thin film  (kg.m -3 ) 22006425  (W.m -1.K -1 ) 0.130.4 (room T°) C (J. K -1.Kg -1 )43.17 @ 50K  (K -1 ) -0.25 10 -6 3.6 10 -6 (room T°)  (dn/dT) 1.01 10 -6 14 10 -6 (room T°) Y (GPa)60140  0.1590.21 n1.44876 @ 30K2.05 Notice: It is reasonable that the parameters at cryogenic temperature do not change considerably with respect to their room T values. As a consequence, at cryogenic temperatures, the coating brownian noise should still dominate on the TE, TR and thermo-optic noises.

8. Thermal Noise Curve compared with the Sensitivity Curve B WP2-WP3 Joint Meeting - Jena - March 1-3, 2010

9. Thermal Noise Curve with violins

10. Modes: pendulum 0.28 Hz, 0.36 Hz, 0.50Hz vertical 0.4 Hz (blades), 20 Hz, 26 Hz violins33 Hz, 67 Hz, 100 Hz, 200 Hz, … WP2-WP3 Joint Meeting - Jena - March 1-3, 2010 M1M1 M2M2 M3M3

11. Thermal Noise Curve compared with the Sensitivity Curve C