1. Nawrodt 23/03/2011 Experimental Approaches for the Einstein Telescope Ronny Nawrodt on behalf of the Einstein Telescope Science Team and the ET DS Writing Team Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena Sonderforschungsbereich Transregio 7 „Gravitationswellenastronomie“ Rencontres de Moriond and GPhyS Colloquium La Thuile 20-27 March 2011

2. Nawrodt 23/03/2011 Overview previous talk: astro-physics with the Einstein Telescope aim: overview of experimental part of the design study and R&D for the Einstein Telescope content: –sensitivity curve and implications for the setup –optical layout –thermal noise of optical components –suspensions –site selection and infrastructure #2/61 Moriond Meeting 2011

3. Nawrodt 23/03/2011 Sensitivity aims initial aim: sensitivity enhancement of about an order of magnitude in all of the frequency range form 1 Hz to 10 kHz #3/61 Moriond Meeting 2011 seismic suspension radiation pressure mirror thermal noise photon shot noise larger mass larger beam dia. higher laser power

4. Nawrodt 23/03/2011 Sensitivity aims To achive that goal all currently available techniques needs to be pushed to the limits and even beyond  large field of upcoming R&D currently: –conceptual design study phase ongoing (2008 – 2011, FP7) –aim: give a potential design for the infrastructure based on our current knowledge, summarise the astrophysical case for such a detector –ET DS document currently put together (~350-400 pages) –presentation of the ET DS 20 May 2011 in Cascina Moriond Meeting 2011 #4/61

5. Nawrodt 23/03/2011 Laser power vs. Cryogenics Moriond Meeting 2011 cryogenic temperatures beneficial high laser power beneficial CONFLICT? #5/61

6. Nawrodt 23/03/2011 Optical layout – Xylophone concept Moriond Meeting 2011 [S. Hild et al., CQG 27 (2010), ET note ET-0135B-10] Low Frequency High Frequency #6/61

7. Nawrodt 23/03/2011 Optical layout – Included Techniques high power lasers –1064 nm for ET-HF (approx. 500 W) –1550 nm for ET-LF (approx. 3 W) arm cavities –ET-HF  3 MW circulating in cavity –ET-LF  18 kW circulating in cavity power and signal recycling 10dB squeezing triangular shape, arm length 10 km LG 33 mode in ET-HF … Moriond Meeting 2011 [see talk by R. Schnabel afterwards] focus on ET-LF #7/61 [see talk by P. Kwee]

8. Nawrodt 23/03/2011 Thermal noise of optical components TN will be important for the ET-LF interferometer starting point: ET-LF mirror mass 211 kg (supress rad. pressure noise) (compare to ~ 40 kg in advanced detectors) arm length: 10 km reduction of thermal noise by: –cryogenics –large beams –new materials –alternative techniques (e.g. replacements for classical coatings) Moriond Meeting 2011 [see talk by F. Brückner in this session] #8/61

9. Nawrodt 23/03/2011 Thermal noise - Bulk Moriond Meeting 2011 Thermo-elastic noise: Brownian thermal noise: [Liu, Thorne 2000] [Braginsky 1999] [Liu, Thorne 2000] [Bondu, Hello, Vinet 1998, Liu, Thorne 2000] beam diameter temperature  =0 possible for some materials, e.g. silicon (@ 18 and 125 K) #9/61

10. Nawrodt 23/03/2011 Thermal noise - Coatings Moriond Meeting 2011 beam diameter temperature Thermo-elastic noise: Brownian thermal noise: [Harry et al. 2002] [Braginsky, Fejer et al. 2004] #10/61

11. Nawrodt 23/03/2011 Thermal noise – Bulk Material Moriond Meeting 2011 amorphous materials show a large loss peak at low temperatures crystalline materials well suited for cryogenic use [Nawrodt, U Jena] #11/61

12. Nawrodt 23/03/2011 Thermal noise – Material Choice two candidate materials Moriond Meeting 2011 SapphireSilicon mechanical loss++ mechanical strength+(+)*++ optical material+o thermal conductivity++ polishing-+ size availability-…++…++ (semicond. industry) * bond strength might not be sufficient (silicate bonding) (further investigation needed) #12/61

13. Nawrodt 23/03/2011 Thermal noise – Coatings coating thermal noise dominates all other thermal noise sources of the mirrors in current detectors (coating = amorphous) large R&D ongoing to understand loss mechanisms Moriond Meeting 2011 [see talk by S. Rowan on Saturday] 300C 600 C 800 C 400C 800 C 600 C 800 C 600 C 800 C 600 C 800 C 400C 600 C 800 C 400C 600 C 800 C 300C 400C 600 C 800 C [I. Martin, U Glasgow] annealing tantala to different temperatures #13/61

14. Nawrodt 23/03/2011 Thermal Noise - Estimates Moriond Meeting 2011 20 K 300 K Si(111) test mass HR stack (18 doublets, Ta 2 O 5 :TiO 2, SiO 2 )  w=90mm needed to supress coating Brownian noise  test mass dia. ~ 50cm, thickness: ~46cm (to reach 211kg) #14/61

15. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 5 K Moriond Meeting 2011 #15/61

16. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 8 K Moriond Meeting 2011 #16/61

17. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 10 K Moriond Meeting 2011 #17/61

18. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 12 K Moriond Meeting 2011 #18/61

19. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 14 K Moriond Meeting 2011 #19/61

20. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 16 K Moriond Meeting 2011 #20/61

21. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 18 K Moriond Meeting 2011 #21/61

22. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 20 K Moriond Meeting 2011 #22/61

23. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 22 K Moriond Meeting 2011 #23/61

24. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 24 K Moriond Meeting 2011 #24/61

25. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 26 K Moriond Meeting 2011 #25/61

26. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 28 K Moriond Meeting 2011 #26/61

27. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 30 K Moriond Meeting 2011 #27/61

28. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 40 K Moriond Meeting 2011 #28/61

29. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 50 K Moriond Meeting 2011 #29/61

30. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 60 K Moriond Meeting 2011 #30/61

31. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 70 K Moriond Meeting 2011 #31/61

32. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 80 K Moriond Meeting 2011 #32/61

33. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 90 K Moriond Meeting 2011 #33/61

34. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 100 K Moriond Meeting 2011 #34/61

35. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 110 K Moriond Meeting 2011 #35/61

36. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 115 K Moriond Meeting 2011 #36/61

37. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 120 K Moriond Meeting 2011 #37/61

38. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 125 K Moriond Meeting 2011 #38/61

39. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 130 K Moriond Meeting 2011 #39/61

40. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 140 K Moriond Meeting 2011 #40/61

41. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 150 K Moriond Meeting 2011 #41/61

42. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 200 K Moriond Meeting 2011 #42/61

43. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 250 K Moriond Meeting 2011 #43/61

44. Nawrodt 23/03/2011 Thermal Noise – Temperature Dependence 300 K Moriond Meeting 2011 #44/61

45. Nawrodt 23/03/2011 Thermal Noise – Choice of Temperature all temperatures below 20 K are suited from the point of thermal noise design choice: 10 K operational temperature at the mirror to allow safety in (so far) unknown/badly known material parameters cryogenic test mass Si(111) temperature 10 K diameter: 45…50cm thickness: 45…60cm mass: 211kg 10 K SEMICONDUCTOR industry Moriond Meeting 2011 #45/61

46. Nawrodt 23/03/2011 Suspensions - Overview requirements: –suspend 211 kg of test mass –low thermal noise contribution –seismic isolation –keep the temperature constant at the test masses (10 K) –reduced gravity gradient noise (underground + GGN reduction) split into upper and lower suspension Moriond Meeting 2011 seismic isolation additionally: going underground for Newtonian noise reduction low thermal noise extraction of heat #46/61

47. Nawrodt 23/03/2011 Suspensions – Upper suspension Moriond Meeting 2011 Superattenuator will be adopted to the ET requirements for the upper stage total height: 17 meters 6 stages (equal dist. spacing) #47/61 S. Braccini et al. GWADW Kyoto

48. Nawrodt 23/03/2011 Suspensions – Lower Stage Moriond Meeting 2011 modelling suspension thermal noise [P. Puppo, Rome] investigation of surface losses in silicon [U Jena/ U Glasgow] #48/61

49. Nawrodt 23/03/2011 Suspensions – Lower Stage Moriond Meeting 2011 suspension design is compliant with the thermal noise requirements [P. Puppo, Rome] #49/61

50. Nawrodt 23/03/2011 Suspensions – Lower Stage Moriond Meeting 2011 heat extraction through lower stage [P. Puppo, Rome] #50/61

51. Nawrodt 23/03/2011 Suspensions – Lower Stage Moriond Meeting 2011 equilibrium temperatures at the test mass INFRASTRUCTURE suspensions vacuum cryogenics #51/61

52. Nawrodt 23/03/2011 Site selection and infrastructure scientific issues for the site selection –low seismic activities („proper“ underground) –far away from disturbance sources (e.g. cities, shores, etc.) –possibility for infrastructure (electricity, roads, building, …) intensive study of seismic at different locations within the ET conceptual design study systematic study and modelling of seismic in different places –seismic noise –FEA based models Moriond Meeting 2011 #52/61

53. Nawrodt 23/03/2011 Site selection and infrastructure Moriond Meeting 2011 #53/61

54. Nawrodt 23/03/2011 Site selection and infrastructure Moriond Meeting 2011 #54/61

55. Nawrodt 23/03/2011 Site selection and infrastructure large focus of the ET design study on infrastructure building the infrastructure will be the largest financial part of the observatory aim: to build a long term infrastructure containing upgradable instruments Moriond Meeting 2011 #55/61

56. Nawrodt 23/03/2011 Site selection and infrastructure Moriond Meeting 2011 artist view of ET end station #56/61

57. Nawrodt 23/03/2011 Site selection and infrastructure - Access Moriond Meeting 2011 vertical vs. horizontal access #57/61

58. Nawrodt 23/03/2011 Site selection and infrastructure Moriond Meeting 2011 NIKHEF #58/61

59. Nawrodt 23/03/2011 Site selection and infrastructure - Cryogenics Moriond Meeting 2011 from: INFN LHe cooling option pulse tube cooling option #59/61

60. Nawrodt 23/03/2011 Site selection and infrastructure - Cryogenics Moriond Meeting 2011 cryotrap cryogenic infrastructure #60/61

61. Nawrodt 23/03/2011 Summary ET will be an infrastructure to host several detectors (2 IF each) 10x more amplitude sensitivity compared to adv. detectors ET conceptual design study very successful  R&D ongoing outcome: design study document containing science case, infra- structure, optics, suspensions, … public day 20/05/2011 in Cascina ET homepage with more information: www.et-gw.eu Moriond Meeting 2011 #61/61