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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“
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Experimental Approachesforthe Einstein Telescope Ronny Nawrodt on behalf ofthe Einstein Telescope Science Team andthe ET DS Writing Team Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena Sonderforschungsbereich Transregio 7 „Gravitationswellenastronomie“ Rencontres de MoriondandGPhyS ColloquiumLa Thuile 20-27 March 2011
Overview • previoustalk: astro-physicswiththe Einstein Telescope • aim: overviewof experimental partofthe design studyand R&D forthe Einstein Telescope • content: • sensitivitycurveandimplicationsforthesetup • opticallayout • thermal noiseofopticalcomponents • suspensions • siteselectionandinfrastructure Moriond Meeting 2011
Sensitivityaims • initialaim: sensitivityenhancementofabout an orderofmagnitude in all ofthefrequencyrange form 1 Hz to 10 kHz seismic suspension radiationpressure larger mass higherlaser power photonshotnoise larger beam dia. mirror thermal noise Moriond Meeting 2011
Sensitivityaims • Toachivethatgoal all currentlyavailabletechniquesneedstobepushedtothelimitsandevenbeyond large fieldofupcoming R&D • currently: • conceptual design studyphaseongoing (2008 – 2011, FP7) • aim: givea potential design fortheinfrastructurebasedon our currentknowledge, summarisetheastrophysicalcasefor such a detector • ET DS documentcurrentlyputtogether (~350-400 pages) • presentationofthe ET DS 20 May 2011 in Cascina Moriond Meeting 2011
Laser power vs. Cryogenics cryogenictemperaturesbeneficial high laser power beneficial CONFLICT? Moriond Meeting 2011
Optical layout – Xylophone concept Low Frequency High Frequency [S. Hild et al., CQG 27 (2010), ET note ET-0135B-10] Moriond Meeting 2011
Optical layout – IncludedTechniques • high power lasers • 1064 nmfor ET-HF (approx. 500 W) • 1550 nmfor ET-LF (approx. 3 W) • arm cavities • ET-HF 3 MW circulating in cavity • ET-LF 18 kW circulating in cavity • power andsignalrecycling • 10dB squeezing • triangularshape, arm length 10 km • LG33mode in ET-HF • … [seetalkbyP. Kwee] [seetalkby R. Schnabel afterwards] focus on ET-LF Moriond Meeting 2011
Thermal noiseofopticalcomponents • TN will beimportantforthe ET-LF interferometer • startingpoint: ET-LF mirrormass 211 kg (supressrad. pressurenoise) (compareto ~ 40 kg in advanceddetectors) arm length: 10 km • reductionof thermal noiseby: • cryogenics • large beams • newmaterials • alternative techniques (e.g. replacementsforclassicalcoatings) [seetalkby F. Brückner in thissession] Moriond Meeting 2011
Thermal noise - Bulk =0 possibleforsomematerials, e.g. silicon (@ 18 and 125 K) • Thermo-elastic noise: • Brownian thermal noise: [Braginsky 1999] [Liu, Thorne 2000] [Liu, Thorne 2000] [Bondu, Hello, Vinet 1998, Liu, Thorne 2000] beam diameter temperature Moriond Meeting 2011
Thermal noise - Coatings • Thermo-elastic noise: • Brownian thermal noise: [Braginsky, Fejer et al. 2004] [Harry et al. 2002] beam diameter temperature Moriond Meeting 2011
Thermal noise – Bulk Material amorphousmaterialsshow a large losspeakatlowtemperatures crystallinematerialswellsuitedforcryogenicuse [Nawrodt, U Jena] Moriond Meeting 2011
Thermal noise – Material Choice • twocandidatematerials * bondstrengthmight not besufficient (silicatebonding) (furtherinvestigationneeded) Moriond Meeting 2011
800 C 800 C 800 C 800 C 800 C 800 C 800 C 800 C 800 C 600 C 600 C 600 C 600 C 600 C 600 C 600 C 400C 400C 400C 400C 300C 300C Thermal noise–Coatings • coating thermal noisedominates all other thermal noisesourcesofthemirrors in currentdetectors (coating = amorphous) • large R&D ongoingtounderstandlossmechanisms annealingtantalato different temperatures [I. Martin, U Glasgow] [seetalkby S. Rowan on Saturday] Moriond Meeting 2011
Thermal Noise - Estimates 300 K 20 K Si(111) testmass HR stack(18 doublets, Ta2O5:TiO2, SiO2) • w=90mm neededtosupresscoatingBrowniannoise • testmassdia. ~ 50cm, thickness: ~46cm (toreach211kg) Moriond Meeting 2011
Thermal Noise – Temperature Dependence 5 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 8 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 10 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 12 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 14 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 16 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 18 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 20 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 22 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 24 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 26 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 28 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 30 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 40 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 50 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 60 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 70 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 80 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 90 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 100 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 110 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 115 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 120 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 125 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 130 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 140 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 150 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 200 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 250 K Moriond Meeting 2011
Thermal Noise – Temperature Dependence 300 K Moriond Meeting 2011
Thermal Noise – Choice ofTemperature • all temperaturesbelow 20 K aresuitedfromthepointof thermal noise • design choice: 10 K operational temperatureatthemirrortoallowsafety in (so far) unknown/badlyknown material parameters • cryogenictestmass • Si(111) • temperature 10 K • diameter: 45…50cm • thickness: 45…60cm • mass: 211kg SEMICONDUCTOR industry 10 K Moriond Meeting 2011
Suspensions - Overview • requirements: • suspend 211 kg oftestmass • low thermal noisecontribution • seismicisolation • keepthetemperatureconstantatthetestmasses (10 K) • reducedgravitygradientnoise (underground + GGN reduction) • splitintoupperandlowersuspension seismicisolation additionally: goingundergroundforNewtoniannoisereduction low thermal noise extractionofheat Moriond Meeting 2011
Suspensions – Uppersuspension S. Braccini et al. GWADW Kyoto • Superattenuator will beadoptedtothe ET • requirementsfortheupperstage • total height: 17 meters • 6 stages (equaldist. spacing) Moriond Meeting 2011
Suspensions – Lower Stage modellingsuspension thermal noise [P. Puppo, Rome] investigationofsurfacelosses in silicon [U Jena/ U Glasgow] Moriond Meeting 2011
Suspensions – Lower Stage suspension design iscompliantwiththe thermal noiserequirements [P. Puppo, Rome] Moriond Meeting 2011
Suspensions – Lower Stage heatextractionthroughlower stage [P. Puppo, Rome] Moriond Meeting 2011
