ET: Einstein Telescope

Transcription

1 ET: Einstein Telescope Michele Punturo INFN Perugia On behalf of the ET design study team ILIAS General meeting, Jaca Feb

2 Evolution of the current GW detectors Current Gravitational Wave interferometric detectors have a well defined evolution line in the next 5-7 years LIGO just completed its S5 scientific run Virgo completed in October 07 its first long scientific run in parallel with LIGO Both the detectors are in upgrade/commissioning mode to implement their 1.5 generation upgrade step (Virgo+, enhanced LIGO) GEO is covering ( astrowatch mode) the down time of LIGO and Virgo in collaboration with the resonant bar detectors see G.Losurdo Talk ILIAS General meeting, Jaca Feb

3 1 st generation GW detectors sensitivities h (Hz -1/2 ) Pulsars h max 1 yr integration LIGO 1 st generation detectors Credit: P.Rapagnani Virgo QNM from BH Collisions, Msun, z=1 BH-BH Inspiral, z = 0.4 GEO QNM from BH Collisions, Msun, 150 Mpc BH-BH Inspiral, 100 Mpc BH-BH Merger 100 Mpc Resonant antennas Core 10 Mpc NS-NS Merger 100 Mpc NS, ε=10-6, 10 kpc NS-NS Inspiral, 300 Mpc Hz ESO May 2, 2006 ILIAS General meeting, Jaca G.Losurdo Feb 2008 INFN Firenze 3 3

4 1.5 generation sensitivities Monolithic FS suspensions Laser amplifier Higher finesse, lower mirror TN ILIAS General meeting, Jaca Feb

5 Advanced detectors Enhanced detectors are a step toward the realization of the 2 nd generation detectors ( advanced ) Also GEO will participate to the network of enhanced detectors with an upgraded version, specialized in the high frequency regime thanks (mainly) to the signal recycling technology GEO HF They are based on small changes of the current detectors with available technologies that anticipate the next step Advanced detectors will be online in the >2013 timeslot They will be based on known technologies currently under preliminary engineering phase High power laser (~200W) and compliant optics Lower thermal noise mirrors (substrates and coatings) Lower thermal noise suspensions (FS monolithic suspensions) Better seismic isolation Active filtering in LIGO Focused improvements of the Virgo Super-Attenuator Signal recycling ILIAS General meeting, Jaca Feb

6 Detection progresses Credit: Richard Powell, Beverly Berger. From LIGO presentation G NS-NS (1.4M S ): 13 15/50 120/170 Mpc h(f) [1/sqrt(Hz)] st generation: Virgo LIGO 1.5 generation: Virgo+ eligo 2 nd generation advvirgo advligo Event rate@snr=7 (year -1 ) ,1 0,01 NS-NS Virgo cluster Great Attractor Frequency [Hz] 0, Radius (Mpc)

7 3 rd generation detectors Second generation detectors: Will permit the detection of Gravitational Waves (GW) Will open the era of the GW astronomy Will be the core business of the next decade in experimental GW research But can we look beyond? Precision GW astronomy needs high SNR to determine the parameters of the astrophysical process Interesting phenomena involves massive bodies that requires low frequency sensitivity in GW detectors We need to think to 3 rd generation GW detectors ILIAS General meeting, Jaca Feb

8 Objectives of a 3 rd generation GW detectors From detection and initial GW astronomy to precision GW astronomy Fundamental Physics: Test general relativity in the strongly non-linear regime Initial and advanced detectors won t have the sensitivity required to test strong field GR (too low SNR) Most tests are currently quoted in the context of LISA, but in a different frequency range We need to have good enough SNR for rare BBH mergers which will enable strong-field test of GR Black hole physics: What is the end state of a gravitational collapse? Astrophysics: Take a census of binary neutron stars in the high red-shift Universe Adv VIRGO/LIGO might confirm BNS mergers, possibly provide links to γ-ray bursts 3 rd generation GW detectors could do much more: see different classes of sources (NS-NS, NS-BH) and contribute to resolve the enigma in the variety of γ-ray bursts ILIAS General meeting, Jaca Feb

9 How to arrive to an European 3 rd generation GW Observatory? Long preparatory path, already started: ILIAS played a determinant role: ILIAS-GW-WP3 realized the correct environment where to discuss, at European level, the evolution of the current detectors and where to merge the efforts addressed to the proposition of a 3 rd generation GW observatory It supported the meetings, the workshops and the preliminary studies All the ET proposal writing meetings have been supported by WP3 WP3 has been also the core of the new WG6 (GW) in the ASPERA road-mapping activity ILIAS-JRA3 (STREGA) partially supported R&D activities in thermal noise issues for 3 rd generation GW detectors European Science Foundation supported an exploratory workshop (Perugia, Sept 2005) that has been a milestone in the definition of the strategy for the proposal of a new Observatory FP7 Design Study has been the perfect environment where to synthesize our ideas in a proposal and compete with other excellent proposals ILIAS General meeting, Jaca Feb

10 ET ET: Einstein Telescope An European 3rd Generation Gravitational Wave Observatory Conceptual design study proposed at the May 2007 FP7 call Capacities Research Infrastructures Collaborative projects ILIAS General meeting, Jaca Feb

11 ET: Participants Participant no. Participant organization name Country 1 European Gravitational Observatory Italy-France 2 Istituto Nazionale di Fisica Nucleare Italy 3 Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.v., acting through Max- Planck-Institut für Gravitationsphysik Germany 4 Centre National de la Recherche Scientifique France 5 University of Birmingham United Kingdom 6 University of Glasgow United Kingdom 7 NIKHEF The Netherlands 8 Cardiff University United Kingdom ILIAS General meeting, Jaca Feb

12 ET: Status of the project The proposal passed the first selection and now we are in an advanced negotiation phase We agreed a budget reduction to 3M for 38Months of activity Main costs: man power and travels Description of Work document accepted by the European Officer We are submitting the signed documents to prepare the Grant Agreement Consortium Agreement under final definition ILIAS General meeting, Jaca Feb

13 Project organization ET Project Institutions Governing Council Executive board Information fluxes Science Team Project organization driven by the Physics : 4 working groups are devoted to the major technical and scientific issues Let see the main technical aspects: Scientific community ILIAS General meeting, Jaca Feb

14 3 main noise sources st generation 2 nd generation 3 rd generation Thermal Noise ILIAS General meeting, Jaca Feb

15 Thermal Noise Long interferometer arms Cryogenic optics Large beams, large optics Non-gaussian beams Improved coatings main noise sources 1 st generation 2 nd generation 3 rd generation Thermal Noise Long interferometer arms Cryogenic optics Large beams, large optics Non-gaussian beams Improved coatings 10km 2nd generation ILIAS General meeting, Jaca Feb

16 Cryogenic Optics Test masses and suspensions thermal noise reduces at low temperature: <X 2 > ~ T Thermoelastic noise of the mirror substrates and coatings decrease: <X 2 > ~ α T 2 Thermal expansion rate α decreases at low temperature; Mechanical Q of some materials increases at low temperature Thermal lensing: Thermal conductivity increases and consequently reduces thermal gradients on the coating; Refraction index variation with temperature is very small at low temperature; 20K β = , Fused 300K β ~ 10 6 ) ILIAS General meeting, Jaca Feb

17 ILIAS supported or related activities Silicon substrates R&D activities in many European Labs: Glasgow, INFN Florence & Perugia, Jena University, Mechanical loss of coated silicon cantilever 3.5x10-5 4th mode undoped Ta 2 O 5 4th mode, TiO 2 doped Ta 2 O 5 3.0x x x x x Temperature (K) Coatings studies R&D activities in many European Labs: Glasgow, INFN Perugia, LMA-Lyon, MPG Hannover, Cryogenic Super attenuator R&D activities in INFN Rome & Pisa ILIAS General meeting, Jaca Feb

18 Thermal Noise Long interferometer arms Cryogenic optics Large beams, large optics Non-gaussian beams Improved coatings main noise sources 1 st generation 2 nd generation 3 rd generation km, 20K 10km ILIAS General meeting, Jaca Feb

19 Thermal Noise Long interferometer arms Cryogenic optics Large beams, large optics Non-gaussian beams Improved coatings main noise sources 1 st generation 2 nd generation 3 rd generation km, 20K, 10cm 10km, 20K ILIAS General meeting, Jaca Feb

20 Non Gaussian Beams Thermal noise in a GW interferometric detector could be further reduced by using flatter beams: ILIAS General meeting, Jaca Feb

21 Thermal Noise Long interferometer arms Cryogenic optics Large beams, large optics Non-gaussian beams Improved coatings main noise sources 1 st generation 2 nd generation 3 rd generation km, 20K, 10cm 10km, 20K, 10cm, non gauss ILIAS General meeting, Jaca Feb

22 3 main noise sources Shot Noise High laser power (maybe Squeezing 1550nm for silicon; less Long thermal interferometer arms 25K) 1 st generation 2 nd generation 3 rd generation Shot Noise 800kW 3MW ILIAS General meeting, Jaca Feb

23 3 main noise sources Shot Noise High laser power Squeezing Long interferometer arms Multiple colocated interferometers 1 st generation 2 nd generation 3 rd generation kW MW MW, 6dB 3MW, 6dB, 10km 3MW, 6dB, 10km, 3ifos ILIAS General meeting, Jaca Feb

24 Co-located interferometers Old idea still under debate Possible implementation: 3 detectors in a triangle configuration Rüdiger, 85 Antenna Patterns: Credit: Cella, Vicerè Angular response of a standard ITF Angular response of the triangle configuration ILIAS General meeting, Jaca Feb

25 10-19 Underground operation Homogeneous soil Seismic 3 main noise sources 1 st generation 2 nd generation 3 rd generation ILIAS General meeting, Jaca Feb

26 Underground operations LISM: 20 m Fabry-Perot interferometer, R&D for LCGT, moved from Mitaka (ground based) to Kamioka (underground) 10 Seismic noise strongly reduced 2 overall gain 10 3 at 4 Hz Credit: K.Kuroda ILIAS General meeting, Jaca Feb

27 Seismic Isolation Shortcut Newtonian Noise! ILIAS General meeting, Jaca Feb Figure: M.Lorenzini

28 Newtonian Credit: G. Cella Surface waves Noise credit: G.Cella Compression waves Credit: G. Cella Surface waves give the main contribution to newtonian noise (Compression waves not included) Surface waves die exponentially with depth Reduction factor NN reduction of 10 Hz with a 20 m radius cave Cave radius [m] 10 2 less seismic noise x 10 4 geometrical reduction 10 6 overall reduction (far from surface) ILIAS General meeting, Jaca Feb Credit: G.Cella

29 3 main noise sources st generation 2 nd generation rd generation Newtonian noise Underground Ground surface ILIAS General meeting, Jaca Feb

30 Conclusions The target of the four Working Groups in the ET project is to try to transform these (and many other) ideas in a coherent conceptual design It is an huge job for a restricted set of persons ET is an emerging facility for the whole Europe and we don t want to limit the contribution to the founding team/institutions The proposal writers created in the project structure a special body that permits the exchange with a larger Scientific Community The Science Team has been considered extremely important by the project referee and already promoted the interest of European and extra- European Scientists Institutions If you are interested, please, contact us Governing Council ET Project Executive board Science Team Scientific community ILIAS General meeting, Jaca Feb

31 Conclusions: Planning You are here Virgo Virgo+ Advanced Virgo GEO GEO HF LIGO LISA Hanford Livingston LIGO+ Advanced LIGO Launch Transfer data E.T. DS PCP Construction Commissioning data ILIAS General meeting, Jaca Feb