1. 4th ILIAS-GW Annual Meeting J.P. Zendri Tuebingen 8-9 October 2007 Materials for Dual: Losses at low Temperature on Si and SiC

2. 4th ILIAS-GW Annual Meeting J.P. Zendri Tuebingen 8-9 October 2007 Materials under investigation Samples shape Silicon single crystal and bonded Silicon Carbide Cantilever beams Disks Experimental set-up (2-300 K) Heater Shacker Capacitive and optical readout Thermometer DUAL requirement  T<10 -8

3. 4th ILIAS-GW Annual Meeting J.P. Zendri Tuebingen 8-9 October 2007 Samples suspension Recently: glued suspension Less invasive on the sample One face of the sample is free Sapphire balls SS spring Sample Glued Sapphire ball

4. 4th ILIAS-GW Annual Meeting J.P. Zendri Tuebingen 8-9 October 2007 Silicon Sample: mono crystalline silicon (n type P doped) disks 4 inch in diameter 0.5 mm in thickness Mode ShapeFrequency 381 Hz 1724 Hz 2512 Hz

5. 4th ILIAS-GW Annual Meeting J.P. Zendri Tuebingen 8-9 October 2007 Dissipation around 125 K H: thickness change of the disk center averaged over a circular area 0.3 mm in diameter Emode: elastic energy stored in the mode Finite size of the sapphire ball Disc thickness change Real nodal point suspension The region around 125 K is dominated by clamping losses H 2 /Emode proportional of the fraction of the elastic energy that couples to the holder FEM calculation: Opt. readout Cap. readout

6. 4th ILIAS-GW Annual Meeting J.P. Zendri Tuebingen 8-9 October 2007 Dissipation mechanism T≠125K Below 50 K Not evidence of clamping losses as at 125K Squeezed gas damping losses order of 10 -8 Surface losses? Coupled field thermoelastic FEM Analysis

7. 4th ILIAS-GW Annual Meeting J.P. Zendri Tuebingen 8-9 October 2007 Glued suspension Advantages Increased thermal conductivity Less invasive Pressure less One face is free (for instance for coating layers)

8. 4th ILIAS-GW Annual Meeting J.P. Zendri Tuebingen 8-9 October 2007 First Bonded Si run Direct bonding Pressure 4 bar Temperature 500 C Post processing annealing 2 hours at 1100 C 3 monocristalline Si disks bonded together using ‘direct bonding’ Single disc thickness 0.3 mm, diameter 4 inch Glued suspension & capacitive readout First Measurements (run in progress) Bonded disk

9. 4th ILIAS-GW Annual Meeting J.P. Zendri Tuebingen 8-9 October 2007 bonded Si: preliminary results h=0.9 mm d=0.15 mm ASSUMING 1. 2. 3. (Dual goal order of 10 -3 ) ?

10. 4th ILIAS-GW Annual Meeting J.P. Zendri Tuebingen 8-9 October 2007 Silicon carbide Considered Samples TypologyPhasePolyTypeSample Shape Supplier Sintered 1AlphaUnknown Beams Bettini (I) Disks Sintered 2BetaUnknownDisksBridgeston (J) Infiltrated C/SiC Beams Cesic (D) Disks Single crystalBeta 4HDisk Cree (USA) 6HDisk

11. 4th ILIAS-GW Annual Meeting J.P. Zendri Tuebingen 8-9 October 2007 Silicon carbide Considered Samples TypologyPhasePolyTypeSample Shape Supplier Sintered 1AlphaUnknown Beams Bettini (I) Disks Sintered 2BetaUnknownDisksBridgeston (J) Infiltrated C/SiC Beams Cesic (D) Disks Single crystalBeta 4HDisk Cree (USA) 6HDisk Already reported

12. 4th ILIAS-GW Annual Meeting J.P. Zendri Tuebingen 8-9 October 2007 Silicon carbide Considered Samples TypologyPhasePolyTypeSample Shape Supplier Sintered 1AlphaUnknown Beams Bettini (I) Disks Sintered 2BetaUnknownDisksBridgeston (J) Infiltrated C/SiC Beams Cesic (D) Disks Single crystalBeta 4HDisk Cree (USA) 6HDisk Already reported Report on this meeting

13. 4th ILIAS-GW Annual Meeting J.P. Zendri Tuebingen 8-9 October 2007 Silicon carbide Considered Samples TypologyPhasePolyTypeSample Shape Supplier Sintered 1AlphaUnknown Beams Bettini (I) Disks Sintered 2BetaUnknownDisksBridgeston (J) Infiltrated C/SiC Beams Cesic (D) Disks Single crystalBeta 4HDisk Cree (USA) 6HDisk Already reported Report on this meeting Still not measured

14. 4th ILIAS-GW Annual Meeting J.P. Zendri Tuebingen 8-9 October 2007 C/SiC disks measurements Samples: disks 3 inch in diameter 1,2,3 mm in thickness Two different carbon matrix Nodal point suspension Capacitive readout Two normal modes investigated

15. 4th ILIAS-GW Annual Meeting J.P. Zendri Tuebingen 8-9 October 2007 C/SiC disks measurements 1. Not evidence of a frequency dependence → Thermoelastic dissipation not dominant 2. Not evidence of a thickness dependence → Surface dissipation not dominant

16. 4th ILIAS-GW Annual Meeting J.P. Zendri Tuebingen 8-9 October 2007 C/SiC carbon matrix size effect Weak dependence Disk A: bigger size of the C-matrix Disk B: Smaller size of the C-matrix

17. 4th ILIAS-GW Annual Meeting J.P. Zendri Tuebingen 8-9 October 2007 Single crystal SiC SAMPLES Disks 2 inch in diameter About 0.3 mm in thickness Two different polytypes 4H and 6H Experimental set-up Nodal suspension (glued) Capacitive readout (comb cap) 4H SiC 6H SiC Capacitive readout

18. 4th ILIAS-GW Annual Meeting J.P. Zendri Tuebingen 8-9 October 2007 Single crystal SiC: preliminary measurements Measurements in progress

19. 4th ILIAS-GW Annual Meeting J.P. Zendri Tuebingen 8-9 October 2007 C/SiC disk Not exluded quantum tunneling of two level systems Hope that at ultralow temperature  scales as T -3 Weak temperature dependence Logaritmic dependence Loss Angle Relative frequency shift

20. 4th ILIAS-GW Annual Meeting J.P. Zendri Tuebingen 8-9 October 2007 C/SiC ultrlow temperature measurement The samples has been assembled past Friday in a DR of the Trento Univ. Experimental set-up SiC Disk for Q measurements Shacker Capactive readout SiC Disk with thermometer

21. 4th ILIAS-GW annual meeting Summary Developed an experimental apparatus for measuring mechanical losses down to 10 -8 at cryogenic temperature The first cryogenic measurements on Si bonded Disc is in progress Regardless the fabrication process the low temperature loss angle of the Silicon Carbide never go down to 10 -6. Ultracryogenic can help? Next year program Extend the measurements at ultracryogenic temperatures Systematic measurements on Si bonding losses Measure the thermal conductivity of bonding Complete the measurements on all the typology of SiC (beta phase) Measurement in collaboration with other Ilias groups

22. 4th ILIAS-GW Annual Meeting J.P. Zendri Tuebingen 8-9 October 2007 Facility for the Q-factor measurement IVC P=10 -6 mbar Sample (disk) Suspension and thermal link Holder (low thermal cond.) Samples prop Actively thermal. (2-300K ) Cryogenic Liquid LHe4 or LN2