LIGO I status and advanced LIGO proposal

Transcription

1 LIGO I status and advanced LIGO proposal Hiro Yamamoto LIGO Lab / Caltech LIGO I» basic design» current status advanced LIGO» outline of the proposal» technical issues GW signals and data analysis ICRR talk on Dec.9,2003 1

2 Sources of today s talk NSF review : G.Sanders, D.H.Shoemaker, M.Zucker, K.Thorne» June 2003 : advanced LIGO review» November 2003 : 2003 annual review of LIGO LSC meeting : B.Barish» November 2003 Program advisory committee : B.Barish» December 2000 : PAC9» November 2001 : PAC11 Presentations» December 2003 : CaJAGWR seminar (Caltech) : S. Marka» December 2003 : 13th GRG (Osaka) : A.Lazzarini advanced LIGO proposal and cost book» ICRR talk on Dec.9,2003 2

3 An International Network of Interferometers LIGO GEO Virgo TAMA detection confidence locate the sources decompose the polarization of gravitational waves complemental - time and direction AIGO ICRR talk on Dec.9,2003 3

4 The LIGO Laboratory Sites Interferometers are aligned along the great circle connecting the sites Hanford, WA (4 km (H1) + 2 km (H2)) 3002 km (L/c = 10 ms) MIT Caltech Livingston, LA (4 km (L1)) ICRR talk on Dec.9,2003 4

5 LIGO Observatories GEODETIC DATA (WGS84) h: m X arm: S W φ: N Y arm: S E λ: W Livingston Observatory Louisiana One interferometer (4km) <- Livingston, LA Hanford Observatory Washington Two interferometers (4 km and 2 km arms) GEODETIC DATA (WGS84) h: m X arm: N W φ: N Y arm: S W ICRR talk on Dec.9, λ: W Hanford, WA ->

6 Interferometer Concept Laser used to measure relative lengths of two orthogonal arms L 1 - L 2 ~ m or h=(l 1 - L 2 )/L~ km (2) thermal (medium freq) 6W 20kW (3) shot (high freq) 0.5W 150W signal ~ L 1 - L 2 (1) seismic (low freq) ICRR talk on Dec.9,2003 6

7 LIGO Beam Tube LIGO beam tube under construction in January ft spiral welded sections girth welded in portable clean room in the field 1.2 m diameter - 3mm stainless 50 km of weld NO LEAKS!! ICRR talk on Dec.9,2003 7

8 LIGO Vacuum Equipment ICRR talk on Dec.9,2003 8

9 Seismic Isolation System Isolation Performance Tubular coil springs with internal damping, layered between steel reaction masses ICRR talk on Dec.9,2003 9

10 A LIGO Mirror Substrates: SiO 2 25 cm Diameter, 10 cm thick Homogeneity < 5 x 10-7 Internal mode Q s > 2 x 10 6 Polishing Surface uniformity < 1 nm rms Radii of curvature matched < 3% Coating Scatter < 50 ppm Absorption < 0.5 ppm Uniformity <10-3 Best mirrors are λ/6000 over the central 8 cm diameter ICRR talk on Dec.9,

11 Core Optics installation and alignment ICRR talk on Dec.9,

12 LIGO Organization & Support DESIGN CONSTRUCTION OPERATION SCIENCE data analysis monitor tool Detector R&D LIGO Laboratory MIT + Caltech ~170 people LIGO Scientific Collaboration 44 member institutions > 400 scientists UK Germany Japan Russia India Spain Australia $ U.S. National Science Foundation ICRR talk on Dec.9,

13 Construction and related R&D costs PAC9 Dec.2000 by B.Barish $ Millions Original Plan - $250M Current Plan - $285M Cooperative Agreement - $292M Performance - $281M Actuals Costs - $278M LIGO Quarter ICRR talk on Dec.9,

14 40 35 LIGO Budgets PAC11 Nov.2001 by B.Barish 30 Hardware to Support of LSC R&D 25 Increase for Ops R&D Support $ Millions Current Funding Basic Operations Increase for Full Operations Basic Ops R&D Support Advanced R&D FY 2001 FY 2002 FY 2003 FY 2004 FY 2005 FY 2006 FY 2001 funding normalized to 12 months shown for comparison ICRR talk on Dec.9,

15 LIGO Commissioning and Science Timeline Analyzed Analysis in Process includes TAMA DT8 Data taking in Process includes TAMA DT9 ICRR talk on Dec.9,

16 Lock Acquisition - developed using simulation - Fast sensors monitor circulating powers, RF sidebands in cavities Sequencing code digitally switches feedback state at proper transition times Loop gains are actively scaled (every sample) to match instantaneous carrier & sideband buildups Designed by Matt Evans (PhD thesis) ICRR talk on Dec.9,

17 Seismic noise & vibration limit at low frequencies Atomic vibrations (Thermal Noise) inside components limit at mid frequencies Quantum nature of light (Shot Noise) limits at high frequencies Myriad details of the lasers, electronics, etc., can make problems above these levels Running at 10-7 What Limits Sensitivity of Interferometers? ICRR talk on Dec.9,

18 S3: All 3 LIGO Interferometers at Extragalactic Sensitivity Displacement spectral density ICRR talk on Dec.9,

19 S2 -- L1 reaches Andromeda M31 in Andromeda ICRR talk on Dec.9,

20 3. Periodic sources S1 sensitivities -- GEO -- L 2km -- H 4km -- L 4km Crab pulsar h 0 h 0 : Amplitude detectable with 99% confidence during observation time T Limit of detectability for rotating NS with equatorial ellipticity, ε = δi/i zz : 10-3, 10-4, 10 kpc Known EM pulsars Values of h 0 derived from measured spin-down PSR J IF spin-down were entirely P = s attributable to GW emissions. f GW = Hz Rigorous astrophysical upper P = s/s limit from energy conservation D = 3.6 kpc ICRR talk on Dec.9,2003 arguments 20

21 Data analysis organization LIGO Scientific Collaboration (LSC) Data analysis is organized in four working groups organized by source type Unmodeled Signals -- SNe, GRBs,» 1. Burst Group: Non-parametric techniques» Excess power in frequency-time domain» Excess amplitude change, rise-time in time domain Deterministic Signals:» 2. Binary Inspiral Group» 3. Pulsars/CW Group Amplitude and frequency evolution parameterized Set of templates covering parameter space matched to data Statistical Signals» 4. Stochastic BG Group Cross-correlation of detector pairs, look for correlations above statistical variations LIGO S1 author list includes more than 300 scientists and representing more than 30 institutions from the USA, Europe, and Asia. ICRR talk on Dec.9,

22 Summary Science Run Metrics RUN GOAL ("SRD") S1 S2 S3* IFO BNS RANGE (kpc) DUTY FACTOR BNS RANGE (kpc) DUTY FACTOR BNS RANGE (kpc) DUTY FACTOR BNS RANGE (kpc) DUTY FACTOR L1 14,000 90% ~150 43% % 1,200 19%* H1 14,000 90% ~30 59% % 2,200 69%* H2 7,000 90% ~40 73% % 1,000 65%* 3-way 75% 24% 22% 11%* *PRELIMINARY--RUN IN PROGRESS ICRR talk on Dec.9,

23 What Next? From S3 to S4 + Stability & uptime» Seismic retrofit at LLO L1» Adapt WFS controls for radiation pressure torques» WFS bandwidth upgrade (wean off optical levers)» Possible wind noise mitigation for LHO Sensitivity» Thermal compensation system (TCS) H1 test» Higher effective laser power (power & sideband overlap) Laser & input optics efficiency improvement Output mode cleaner (OMC) [possibly]» Finish acoustic mitigation Enclosures for other output ports Relocate electronics racks remotely L1 test» Electronics cleanup: EMC upgrade L1 test» Custom low-noise DAC's, other electronics upgrades ICRR talk on Dec.9,

24 Advanced LIGO proposed in early 2003 Active Seismic Multiple Suspensions Silica Suspension Sapphire Optics Higher Power Laser Dual recycling ICRR talk on Dec.9,

25 Dual Recycling Interferometer ICRR talk on Dec.9,

26 Anatomy of the projected Advanced LIGO detector performance Newtonian background, estimate for LIGO sites Seismic cutoff at 10 Hz Suspension thermal noise Test mass thermal noise, / 2 e N o i s z1 H) / f ( h n i a S t r Initial LIGO Advanced LIGO Unified quantum noise dominates at most frequencies for full power, broadband tuning Frequency (Hz) 10 Hz 100 Hz 1 khz Advanced LIGO's Fabry-Perot Michelson Interferometer is flexible can tailor to what we learn before and after we bring it on line, to the limits of this topology ICRR talk on Dec.9,

27 Initial and Advanced LIGO Factor 10 better amplitude sensitivity» (Reach) 3 = rate Factor 4 lower frequency bound NS Binaries: for three interferometers,» Initial LIGO: ~20 Mpc» Adv LIGO: ~350 Mpc BH Binaries:» Initial LIGO: 10 M o, 100 Mpc» Adv LIGO : 50 M o, z=2 Stochastic background:» Initial LIGO: ~3e-6» Adv LIGO ~3e-9 ICRR talk on Dec.9,

28 Baseline plan LIGO(122M$)&LSC[UK(11.5),Germany(11.5),Australia(2.5)] Initial LIGO Observation at design sensitivity » Significant observation within LIGO Observatory» Significant networked observation with GEO, VIRGO, TAMA Structured R&D program to develop technologies» Conceptual design developed by LSC in 1998» Cooperative Agreement carries R&D to Final Design 2003: Proposal for fabrication, installation» NSF considering proposal and timeline Proposal calls for project start in 2005» Sapphire Test Mass material, seismic isolation fabrication long leads» Prepare a stock of equipment for minimum downtime, rapid installation Start installation in 2007» Baseline is a staggered installation, Livingston and then Hanford Coincident observations by 2010» At an advanced level of commissioning ICRR talk on Dec.9,

29 Sensing for Advanced LIGO Build on initial LIGO layout» retain Fabry-Perot cavities, power recycling Increase the laser power to a practical limit to lower shot noise» Laser power require TEM00, stability in frequency and intensity» Absorption in optics state-of-the-art substrates and coatings, compensation system to correct for focussing» ~180 W input power is the practical optimum for Advanced LIGO» Leads to ~0.8 MW in cavities (6cm radius beams, though)» Significant motion due to photon pressure quantum limited! Modify optical layout: Add signal recycling mirror» Gives resonance for signal frequencies can be used to optimize response» Couples photon shot noise and backreaction some squeezing of light Laser ICRR talk on Dec.9,

30 Managing Stray forces in Advanced LIGO Seismic Isolation: use servo-control techniques and low-noise seismometers to slave optics platform to inertial space» Decreases motion in the gravitational-wave band to a negligible level» Decreases motion in controls band, moving forces away from test mass Suspension thermal noise: all-silica fiber construction» Intrinsically low-loss material» Welded and contacted construction also very low loss Substrate thermal noise: use monolithic Sapphire» High Young s modulus» Low mechanical loss» (fallback: very low-loss silica) Optical coating thermal noise: develop low-loss materials and techniques» Area of active development ICRR talk on Dec.9,

31 Advanced LIGO R&D LIGO with LSC(LIGO Scientific Collaboration) making good progress Laser: in 2003,» selected baseline power head design,» supported prototyping of design, observe >1/2 final power goal in _ of system.» Demonstrated intensity stabilization to requirements at 40 Hz and higher, within factor of 5 at most stringent frequency (10 Hz) Substrates: in 2003,» Received full-size 40 kg, 32 cm diameter sapphire substrates» Found mechanical losses in these substrates to meet requirements» Characterized absorption in these substrates, supported successful annealing techniques on smaller pieces to reduce absorption scaling up now» New high Q measurements of small (200e6) and LIGO-sized (120e6) of fused silica; supported annealing on small pieces to reduce mechanical losses scaling up now Coatings, in 2003,» Refined models for coating thermal noise» Observed coating thermal noise in two experiments, consistent with theory» Measured and supported measurements of mechanical losses on trial coatings» Developed strategy for coating development, put plan into motion ICRR talk on Dec.9,

32 Summary report of the NSF review on advanced LIGO Advanced LIGO will provide the capability to observe a variety of astrophysical phenomena including inspiral events, continuouswave sources, bursts, and stochastic backgrounds. Achievement of the design strain sensitivity (more than a factor of ten beyond Initial LIGO) is feasible and detection of events is plausible. Detection of any source would be a dramatic direct confirmation of the existence of gravitational waves and would have exciting and wide-ranging implications for gravitational physics, astrophysics, and our understanding of the universe. The committee agrees that the current state of the proposed project is at a sufficiently mature level that the process leading to construction should proceed. Although technical challenges remain, the plan for solving the technical problems appears sound and no major obstacles have been identified that would justify delaying the construction of Advanced LIGO. ICRR talk on Dec.9,