1. Nawrodt 10/07 #1/21 R. Nawrodt, A. Schröter, C. Schwarz, D. Heinert, M. Hudl, W. Vodel, A. Tünnermann, P. Seidel STREGA Meeting Tübingen 10/2007 08.10.2007 Friedrich-Schiller-Universität Jena Current bulk material research in Jena

2. Nawrodt 10/07 #2/21 Outline setup changes bulk material research nodal support coating/grating, all-reflective components

3. Nawrodt 10/07 #3/21 Setup -1- reminder: measurement technique, ring-down experiment Si(100),  3“  12 mm, 5.8 K, f 0 = 14886 Hz Q = 4.5  10 8

4. Nawrodt 10/07 #4/21 Setup -2- 1 probe chamber 2 experimental platform 3 LHe tank 4 LN2 tank 5 heat radiation shields 1 viewport 2 probe chamber 3 platform 4 substrate (1) 5 substrate (2) 6 interferometer reminder: cryostat Nawrodt et al. Cryogenics 21 (2006) 456

5. Nawrodt 10/07 #5/21 Setup -3- old setupnew setup combination alumium and stainless steel  thermal expansion fully stainless steel  less problems with thermal expansion full automatic control (temperature, frequency, amplitudes…)

6. Nawrodt 10/07 #6/21 Setup -4- setup ready for cantilever measurements cryostate setup “small setup” interferometric read-out capacitive readout

7. Nawrodt 10/07 #7/21 Bulk material research -1- investigation of potential substrate materials big samples, usually 3”, 4” or 6” diameter thickness: between 6…100mm (up to 250mm possible) different materials: fused silica, quartz, calcium fluoride, silicon

8. Nawrodt 10/07 #8/21 Bulk material research -2- reminder: material overview Si (100) Quartz (cryst.) Fused Silica

9. Nawrodt 10/07 #9/21 Bulk material research -3- reminder: crystalline quartz (elementary processes) substrate:  3“  12 mm mode frequency: 11565 Hz (300 K) Impurities Phonons Zimmer et al. Rev. Sci. Instrum. 78 (2007) 063905

10. Nawrodt 10/07 #10/21 Bulk material research -4- understanding anisotropy of the relaxation strength investigation of 3 cuts (x-, y-, z-cut from one single crystal) dia. 45mm, thickness: 50mm (limited by single crystal size)  … relaxation strength  … relaxation time

11. Nawrodt 10/07 #11/21 Bulk material research -5- silicon research (orientation) Si  75 mm  75 mm boron doped (10 14 cm -3 ) fundamental drum mode

12. Nawrodt 10/07 #12/21 Bulk material research -6- big silicon substrates (dia. 150mm  86mm) Temperature [K] mechanical Q-factor dips between 100 and 300K “flat” profile at low temperatures

13. Nawrodt 10/07 #13/21 Towards a nodal support -1- “high” temperature dips unclear big change in resonant frequency of substrate Temperature [K] Resonant Frequency [Hz] interaction with suspension wire?

14. Nawrodt 10/07 #14/21 Towards a nodal support -2- changes during adjustment (rotating of the substrate in the suspension wire) optimisation step ringdown time [s] optimisation step ringdown time [s] crystalline quartz 10° rotation per step silicon 10° rotation per step

15. Nawrodt 10/07 #15/21 Nodal support -1- pendulum suspensionnodal support

16. Nawrodt 10/07 #16/21 Nodal support -2- exciter (comb-like structure)

17. Nawrodt 10/07 #17/21 Nodal support -3- sapphire sphere brass spring (not shown)

18. Nawrodt 10/07 #18/21 Coating/grating research -1- quartz substrate grating structure (as will be used) 1st layer silica multilayer

19. Nawrodt 10/07 #19/21 Coating/grating research -2- substrate + grating + grating + 200 nm SiO 2 + graing + 200 nm SiO 2 + HR cryst. quartz,  3“  12 mm, 11670 Hz

20. Nawrodt 10/07 #20/21 Coating/grating research -3- extracted coating/grating losses Nawrodt et al. New J. Phys. 9 (2007) 225 higher sensitivity (cantilever?) frequency dependence?

21. Nawrodt 10/07 #21/21 Summary setup: bulk substrates, cantilevers (Iain’s talk), nodal support bulk material: silicon research on the way, crystaline quartz as toy material to understand relaxational processes coating/grating research: influence of grating structure possible collaboration next year best time for workshop in Jena in spring?