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					      LIGO
Status and Plans




Barry Barish / Gary Sanders
         13-May-02
                               LIGO
                      overall strategy
 Strategy presented to NSB by Thorne / Barish in 1994

 Search with a first generation interferometer where detection
  of gravitational waves are „plausible‟
    » LIGO I uses demonstrated technologies
    » Design sensitivity h ~ 10-21
    » Plan is to interleave interferometer studies and improvements
      with incrementally improving data runs
    » Search Goal: one year of integrated data at ~ design sensitivity


 Advanced LIGO – detection “likely”
    »   Do enabling R&D and design in parallel with LIGO I
    »   Incremental upgrades to laser, suspensions, optics, test masses
    »   Sensitivity: ~ 15x improvement (rate improves by 103 !!)
    »   Time scale: operational by 2008
 13-May-02                 Baltimore / Koonin Briefing                   2
              Astrophysical Signatures
                           physics goals
 Compact binary inspiral:           “chirps”
     » NS-NS waveforms are well described
     » BH-BH need better waveforms
     » search technique: matched templates

 Supernovae / GRBs:                 “bursts”
     » burst signals in coincidence with signals in electromagnetic
       radiation
     » prompt alarm (~ one hour) with neutrino detectors

 Pulsars in our galaxy:             “periodic”
     » search for observed neutron stars (frequency, doppler shift)
     » all sky search (computing challenge)
     » r-modes

 Cosmological Signals               “stochastic background”

13-May-02                 Baltimore / Koonin Briefing                 3
                    Known Pulsars
            maximum gravitational wave signal




                                                  Jones, gr-qc/0111007




13-May-02           Baltimore / Koonin Briefing                          4
            “Periodic Signals”
             pulsars sensitivity

                                       Pulsars in our galaxy
                                             » non axisymmetric:
                                                 10-4 < e < 10-6

                                             » science: neutron star
                                             precession; interiors

                                             » narrow band searches
                                             best

                                             » all sky searches




13-May-02      Baltimore / Koonin Briefing                             5
                   LIGO Plans
                       schedule
    1996    Construction Underway (mostly civil)

    1997    Facility Construction (vacuum system)
    1998    Interferometer Construction (complete facilities)
    1999    Construction Complete (interferometers in vacuum)
    2000    Detector Installation (commissioning subsystems)
    2001    Commission Interferometers (first coincidences)
    2002    Sensitivity studies (initiate short data taking runs)
    2003+   LIGO I data run (one year integrated data at h ~ 10-21)

    2006    Begin Advanced LIGO installation




13-May-02             Baltimore / Koonin Briefing                     6
                     The LIGO Observatories




 LIGO Hanford Observatory [LHO]                    LIGO Livingston Observatory [LLO]
       26 km north of Richland, WA                       42 km east of Baton Rouge, LA




13-May-02                        Baltimore / Koonin Briefing                             7
                     Summary
            integrated schedule




13-May-02    Baltimore / Koonin Briefing   8
                            LIGO
            costs & commitments




13-May-02     Baltimore / Koonin Briefing   9
                                 LIGO
            contingency vs percent complete




13-May-02          Baltimore / Koonin Briefing   10
                      Staffing
                         history




13-May-02   Baltimore / Koonin Briefing   11
                            Staffing
            labor distribution projections




13-May-02         Baltimore / Koonin Briefing   12
                          Major NSF Reviews
                     Operations Renewal - 2001
 Review of Operations Proposal
 Review of Advanced R&D Proposal
     » Requested $175M for 5 years of operations
     » Outstanding reviews –
            – “The Review Panel was extremely impressed with all aspects of
              the LIGO Program and feels that it should receive the highest
              possible rating”
            – “The Review Panel recommends that the NSF, even in the
              eventuality of overall fiscal pressures, support the LIGO program
              at the requested level.”
     » Funding approved by NSB (Aug 01) at $160M
 Annual LIGO Review
     » Concentrated on computing facilities
 Next review – Fall 02



13-May-02                      Baltimore / Koonin Briefing                    13
               NSF Review Panel
              LIGO Goals and Plans

“The two goals of the program for the next five-year period
were described to the Panel. The first goal is the operation of
the LIGO I interferometers to search for gravitational waves
with the strain sensitivity of h=10-21. This sensitivity is
sufficient to make plausible, but not to guarantee, significant
discoveries. The second goal is to pursue the R&D necessary
for the design and construction of the Advanced LIGO
interferometers with a 15-fold sensitivity improvement. Since
the number of detectable sources is expected to scale as the
cube of the sensitivity, Advanced LIGO is crucial in realizing
the scientific goals of the program. The Review Panel felt that
both of these goals are of paramount importance, and that the
balance between the resources planned by LIGO on these two
efforts is about right.”

13-May-02              Baltimore / Koonin Briefing            14
                    LIGO Plans
                       schedule

       1996    Construction Underway (mostly civil)
       1997    Facility Construction (vacuum system)
       1998    Interferometer Construction (complete facilities)
       1999    Construction Complete (interferometers in vacuum)
       2000    Detector Installation (commissioning subsystems)
       2001    Commission Interferometers (first coincidences)
       2002    Sensitivity studies (initiate short data taking runs)
       2003+   LIGO I data run (one year integrated data at h ~ 10-21)

       2006    Begin LIGO II installation




13-May-02             Baltimore / Koonin Briefing                        15
                                             Laser
                                      stabilization
   Deliver pre-stabilized laser light                Provide actuator inputs for
    to the 15-m mode cleaner                           further stabilization
     • Frequency fluctuations
                                                         • Wideband
     • In-band power fluctuations
                                                         • Tidal
     • Power fluctuations at 25 MHz



            Tidal       Wideband
                                                                      4 km
                                                      15m
                    10-Watt
                     Laser



                 PSL                           IO                 Interferometer
           10-1 Hz/Hz1/2              10-4 Hz/ Hz1/2              10-7 Hz/ Hz1/2

     13-May-02                     Baltimore / Koonin Briefing                     16
                               LIGO
                                laser
     Nd:YAG

     1.064 mm

     Output power > 8W in
      TEM00 mode




    13-May-02                Baltimore / Koonin Briefing   17
            Prestabalized Laser
                 performance

                                                > 25,000 hours
                                                 continuous operation

                                                Frequency and lock very
                                                 robust

                                                TEM00 power > 8 watts

                                                Non-TEM00 power < 10%

                                                Improvements in optical
                                                 path brought noise to
                                                 better than design at low
                                                 frequencies




13-May-02      Baltimore / Koonin Briefing                          18
            Lock Acquisition




13-May-02   Baltimore / Koonin Briefing   19
                                   E7 Run Summary
                                    LIGO + GEO Interferometers


                                   28 Dec 2001 - 14 Jan 2002 (402 hr)
                       Singles data                                           Coincidence Data
                All segments    Segments >15min                        All segments    Segments >15min
                                                         2X: H2, L1
L1 locked     284hrs (71%)       249hrs (62%)            locked       160hrs (39%)       99hrs (24%)
L1 clean      265hrs (61%)       231hrs (53%)            clean        113hrs (26%)       70hrs (16%)
L1 longest clean segment: 3:58                           H2,L1 longest clean segment: 1:50

                                                         3X : L1+H1+ H2
H1 locked     294hrs (72%)       231hrs (57%)
                                                         locked       140hrs (35%)      72hrs (18%)
H1 clean      267hrs (62%)       206hrs (48%)
                                                         clean         93hrs (21%)      46hrs (11%)
H1 longest clean segment: 4:04
                                                         L1+H1+ H2 : longest clean segment: 1:18

H2 locked     214hrs (53%)       157hrs (39%)
H2 clean      162hrs (38%)       125hrs (28%)
                                                         4X: L1+H1+ H2 +GEO:
H2 longest clean segment: 7:24
                                                                         77 hrs (23 %)       26.1 hrs (7.81 %)




    13-May-02                            Baltimore / Koonin Briefing                                   20
                                           LIGO I
                                 the noise floor

 Interferometry is limited
by three fundamental
noise sources
    seismic noise at the
   lowest frequencies
    thermal noise at
   intermediate frequencies
    shot noise at high
   frequencies

Many other noise
sources lurk underneath
and must be controlled as
the instrument is
improved


 13-May-02                    Baltimore / Koonin Briefing   21
            Engineering Test Run
               2 weeks – Jan 02

                 PRELIMINARY

                                                      4 Km Hanford



                                             4 Km Livingston




                                                     2 Km Hanford


13-May-02      Baltimore / Koonin Briefing                     22
                 Strain Spectra for E7
            comparison with design sensitivity




   LIGO I
   Design



13-May-02            Baltimore / Koonin Briefing   23
            Engineering Run
            detecting earthquakes

                                          From electronic logbook 2-Jan-02



                                         An earthquake occurred, starting at
                                         UTC 17:38.
                                         The plot shows the band limited rms
                                         output in counts over the 0.1- 0.3Hz
                                         band for four seismometer channels.
                                         We turned off lock acquisition and
                                         are waiting for the ground motion to
                                         calm down.




13-May-02        Baltimore / Koonin Briefing                          24
17:03:03
      01/02/2002
             =========================================================================
             Seismo-Watch
             Earthquake Alert Bulletin No. 02-64441
             =========================================================================
             Preliminary data indicates a significant earthquake has occurred:
             Regional Location: VANUATU ISLANDS
             Magnitude: 7.3M


             Greenwich Mean Date: 2002/01/02
             Greenwich Mean Time: 17:22:50
             Latitude: 17.78S
             Longitude: 167.83E
             Focal depth: 33.0km
             Analysis Quality: A


             Source: National Earthquake Information Center (USGS-NEIC)
             Seismo-Watch, Your Source for Earthquake News and Information.
             Visit http://www.seismo-watch.com
             =========================================================================
             All data are preliminary and subject to change.
             Analysis Quality: A (good), B (fair), C (poor), D (bad)
              Magnitude: Ml (local or Richter magnitude), Lg (mblg), Md (duration),
           13-May-02                             Baltimore / Koonin Briefing              25
              =========================================================================
            Detecting the Earth Tides
                    Sun and Moon




13-May-02        Baltimore / Koonin Briefing   26
              Stochastic Background
            projected sensitivities evolution




13-May-02             Baltimore / Koonin Briefing   27
            Improvements LHO 2K – Jan 02
                        preliminary

                                                 • Closed
                                                 feedback loop
                                                 from arms to
                                                 laser frequency


                                                 • Reallocation
                                                 of gains within
                                                 length control
                                                 servo system




13-May-02          Baltimore / Koonin Briefing              28
            Interferometer Sensitivities
                 Evolution of TAMA




13-May-02         Baltimore / Koonin Briefing   29
                    Noise Level
            contributing components




13-May-02      Baltimore / Koonin Briefing   30
                          Run Plan
            commissioning & data taking

 • Science 1 run: 13 TB data “Upper Limits”
     » 29 June - 15 July
     » 2.5 weeks - comparable to E7
     » Target sensitivity: 200x design
 • Science 2 run: 44 TB data “Upper Limits”
     » 22 November - 6 January 2003
     » 8 weeks -- 15% of 1 yr
     » Target sensitivity: 20x design
 • Science 3 run: 142 TB data “Search Run”
     » 1 July 2003 -- 1January 2004
     » 26 weeks -- 50% of 1 yr
     » Target sensitivity: 5x design


13-May-02                 Baltimore / Koonin Briefing   31
                LIGO Scientific Collaboration
                                               LIGO I

US Universities:                                     International Members:
    Caltech LIGO/CaRT/CEGG/CACR                         ACIGA (Australia)
    Carleton                                            GEO 600 (UK/Germany)
    Cornell                                             IUCAA (Pune, India)
    Cal State University Dominguez Hills
    Florida
•    Louisiana State                                 US Agencies & Institutions
    Louisiana Tech                                      FNAL (DOE)
    Michigan                                            Goddard-GGWAG (NASA)
    MIT LIGO                                            Harvard-Smithsonian
    Oregon
    Penn State
                                                     International partners (have
    Southern
    Syracuse
                                                        MOUs with LIGO Laboratory):
    Texas-Brownsville                                   TAMA (Japan)
    Wisconsin-Milwaukee                                 Virgo (France/Italy)




                  21 Institutions, 26 Groups, 281 Members
    13-May-02                       Baltimore / Koonin Briefing                   32
                              LIGO
                         summary
 LIGO construction completed in 2000

 LIGO commissioning and testing „on track‟

 Engineering test runs underway, during period when emphasis is
  on commissioning, detector sensitivity and reliability.

 Short upper limit data runs interleaved


 First Science Search Run : first search run will begin during 2003

 Significant improvements in sensitivity ~ 2008


   13-May-02              Baltimore / Koonin Briefing           33

				
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