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Advanced Gravitational-wave Detectors and LIGO-India. Stan Whitcomb LIGO/Caltech 22 October 2011. Astrophysical Sources for Terrestrial GW Detectors. Compact binary inspiral: “chirps” NS-NS, NS-BH, BH-BH Supernovas or GRBs: “bursts”

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Advanced gravitational wave detectors and ligo india

Advanced Gravitational-wave Detectors and LIGO-India

Stan Whitcomb LIGO/Caltech

22 October 2011


Astrophysical sources for terrestrial gw detectors

Astrophysical Sources for Terrestrial GW Detectors

  • Compact binary inspiral:“chirps”

    • NS-NS, NS-BH, BH-BH

  • Supernovas or GRBs:“bursts”

    • GW signals observed in coincidence with EM or neutrino detectors

  • Pulsars in our galaxy: “periodic waves”

    • Rapidly rotating neutron stars

    • Modes of NS vibration

  • Cosmological: “stochastic background”

    • Probe back to the Planck time (10-43 s)

LIGO-India, October 2011


Advanced gravitational wave detectors and ligo india

Detecting GWs with Interferometry

Suspended mirrors act as “freely-falling” test masses in horizontal plane for

frequencies f >> fpend

Terrestrial detector,L ~ 4 km

For h ~ 10–22 – 10–21 (Initial LIGO)

DL ~ 10-18 m

Useful bandwidth 10 Hz to 10 kHz,

determined by “unavoidable” noise (at low frequencies) and expected maximum source frequencies (high frequencies)

LIGO-India, October 2011


Laser interferometer gravitational wave observatory ligo

Laser Interferometer Gravitational-wave Observatory (LIGO)

HANFORD

Washington

MIT

Boston

3

0

0

(

8

±

1

k

0

m

m

s

)

CALTECH

Pasadena

LIVINGSTON

Louisiana

LIGO-India, October 2011


Optical configuration

Power Recycled

end test mass

with Fabry-Perot Arm Cavities

Light bounces back and forth along arms about 100 times

Light is “recycled” about 50 times

beam splitter

signal

Optical Configuration

Michelson

Interferometer

input test mass

Laser

LIGO-India, October 2011


Initial ligo sensitivity goal

Initial LIGO Sensitivity Goal

  • Strain sensitivity <3x10-23 1/Hz1/2at 200 Hz

  • Sensing Noise

    • Photon Shot Noise

    • Residual Gas

  • Displacement Noise

    • Seismic motion

    • Thermal Noise

    • Radiation Pressure

LIGO-India, October 2011


Ligo sensitivity

LIGO Sensitivity

LIGO-India, October 2011


What s next for ligo advanced ligo

What’s next for LIGO? Advanced LIGO

  • Take advantage of new technologies and on-going R&D

    • Active anti-seismic system operating to lower frequencies

    • Lower thermal noise suspensions and optics

    • Higher laser power

    • More sensitive and more flexible optical configuration

x10 better amplitude sensitivity

x1000rate=(reach)3

 1 day of Advanced LIGO

» 1 year of Initial LIGO !

2008 fabrication start,installation began 2011

LIGO-India, October 2011


Advanced gravitational wave detectors and ligo india

Advanced LIGO Performance

  • Newtonian background,estimate for LIGO sites

  • Seismic ‘cutoff’ at 10 Hz

  • Suspension thermal noise

  • Test mass thermal noise

  • Quantum noise dominates at most frequencies

10-21

Initial LIGO

10-22

Strain

Advanced LIGO

10-23

10-24

10 Hz

100 Hz

1 kHz

LIGO-India, October 2011


Initial ligo laser

Initial LIGO Laser

Stabilization cavities

for frequency

and beam shape

Custom-built

10 W Nd:YAG

Laser

LIGO-India, October 2011


Advanced ligo laser

Advanced LIGO Laser

  • Designed and contributed by Albert Einstein Institute

  • Higher power

    • 10W -> 180W

  • Better stability

    • 10x improvement in intensity and frequency stability

LIGO-India, October 2011


Initial ligo mirrors

Initial LIGO Mirrors

  • Substrates: SiO2

    • 25 cm Diameter, 10 cm thick

    • Homogeneity < 5 x 10-7

    • Internal mode Q’s > 2 x 106

  • Polishing

    • Surface uniformity < 1 nm rms(l / 1000)

    • Radii of curvature matched < 3%

  • Coating

    • Scatter < 50 ppm

    • Absorption < 2 ppm

    • Uniformity <10-3

  • Production involved 5 companies, CSIRO, NIST, and LIGO

LIGO-India, October 2011


Advanced ligo mirrors

Advanced LIGO Mirrors

  • All substrates delivered

  • Polishing underway

  • Reflective Coating process starting up

  • Larger size

    • 11 kg -> 40 kg

  • Smaller figure error

    • 0.7 nm -> 0.35 nm

  • Lower absorption

    • 2 ppm -> 0.5 ppm

  • Lower coating thermal noise

LIGO-India, October 2011


Initial ligo vibration isolation

102

100

10-2

10-6

Horizontal

10-4

10-6

10-8

Vertical

10-10

Initial LIGO Vibration Isolation

HAM stack

in air

BSC stackin vacuum

LIGO-India, October 2011


Advanced ligo seismic isolation

Advanced LIGO Seismic Isolation

  • Two-stage six-degree-of-freedom active isolation

    • Low noise sensors, Low noise actuators

    • Digital control system to blend outputs of multiple sensors, tailor loop for maximum performance

LIGO-India, October 2011


Initial ligo test mass suspension

Initial LIGO Test Mass Suspension

  • Simple single-loop pendulum suspension

  • Low loss steel wire

    • Adequate thermal noise performance, but little margin

  • Magnetic actuators for control

LIGO-India, October 2011


Advanced ligo suspensions

Advanced LIGO Suspensions

four stages

40 kg silica test mass

  • UK designed and contributed test mass suspensions

  • Silicate bonds create quasi-monolithic pendulums using ultra-low loss fused silica fibers to suspend interferometer optics

    • Pendulum Q ~105 -> ~108

LIGO-India, October 2011

17


A global array of gw detectors source localization

DL = c dt

q

1

2

A Global Array of GW Detectors:Source Localization

Virgo

GEO

LIGO

LCGT

Locate sources using multi-site arrival times (“aperture synthesis”)

LIGO-India, October 2011


Ligo and virgo alone

LIGO and Virgo Alone

Planned detector network has limited ability to locate sources, particularly near the celestial equator

LIGO-India, October 2011


Advanced gravitational wave detectors and ligo india

Completing the Global Network

LIGO-India

Virgo

GEO

LIGO

TAMA/LCGT

LIGO-India, October 2011


Ligo and virgo plus ligo india

LIGO and Virgo Plus LIGO-India

Adding LIGO-India to existing network gives nearly all-sky coverage

LIGO-India, October 2011


Ligo and virgo alone1

LIGO and Virgo Alone

LIGO-India, October 2011


Ligo india concept

LIGO-India Concept

  • A direct partnership between LIGO Laboratory and IndIGO to build an Indian interferometer

    • LIGO Lab (with its UK, German and Australian partners) provides components for one Advanced LIGO interferometer, unit #3, from the Advanced LIGO project

    • India provides the infrastructure (site, roads, building, vacuum system), “shipping & handling,” staff, installation & commissioning, operating costs

  • The interferometer, the third Advanced LIGO instrument, would be operated as part of LIGO to maximize the scientific impact of LIGO-India

  • Key deadline: LIGO needs a commitment from India by March 2012—otherwise, must begin installation of the LIGO-India detector at our US facility

LIGO-India, October 2011


What does india provide

What Does India Provide?

  • Participation in Advanced LIGO installation and commissioning in US

    • Training, but also early participation in detector development

  • Site

    • LIGO provides requirements and its design

  • Buildings

    • LIGO provides requirements and its design

  • Vacuum system

    • LIGO provides detailed drawings for up-dating, assistance for achieving low out-gassing performance

  • Staff to install, commission and operate

    • LIGO provides training for Indian staff, collaboration and support

  • All data are shared throughout the collaboration

LIGO-India, October 2011


Ligo livingston observatory

LIGO Livingston Observatory

LIGO-India, October 2011


Advanced gravitational wave detectors and ligo india

India provides a facility with-

Vacuum system

Site, buildings


Ligo beam tube

LIGO Beam Tube

  • LIGO beam tube under construction in January 1998

  • 16 m spiral welded sections

  • girth welded in portable clean room in the field

1.2 m diameter - 3mm stainless

50 km of weld

NO LEAKS !!

LIGO-India, October 2011


Ligo vacuum equipment

LIGO Vacuum Equipment

LIGO-India, October 2011


Corner station chambers

Corner Station Chambers

  • Align, assemble, test under portable clean rooms

LIGO-India, October 2011


Beamtube gate valves

Beamtube Gate Valves

  • Large gate valves to isolatebeamtubes,LN2 traps

LIGO-India, October 2011


Detector installation using cleanrooms

Detector Installation using Cleanrooms

  • Chamber access through large doors

LIGO-India, October 2011


Ham chamber

HAM Chamber

LIGO-India, October 2011


Optics installation under cleanroom conditions

Optics Installation Under Cleanroom Conditions

LIGO-India, October 2011


Ligo lab concerns who does it

LIGO Lab Concerns:Who Does it?

  • Number of experienced interferometer experts is small

    • Initially, IndIGO mostly theorists or data analysts

    • Growing interest from experimental community, but still new to GWs

    • August: Rana Adhikari visit to India to assess capability and to recruit

  • Expect to have a training program in LIGO for interferometer specialists

    • Started last year in anticipation of LIGO-Australia

    • Working to recruit postdocs to work with LIGO (2 so far)

  • Need to identify Project team

    • Most likely source from National Labs or Centres

    • Requires official standing with government departments for commitments, but some expressions of support

LIGO-India, October 2011


Ligo lab concerns site

LIGO Lab Concerns :Site

  • So far, no definite site identified and characterized

  • In terms of ‘Science’, specific location with in India (including orientation) is not critical

    • Result of simulation studies by Sathya et al.

  • Site selection guidance given to IndIGO

    • Data collection could take some months

  • My opinion: I expect that finding a suitable site is possible (requirements are not that extreme)

    • Difficult issues will be ability to secure it and timescale

    • Discussions about possible site hampered initially by lack of approved project status

LIGO-India, October 2011


Nsf review of ligo india

NSF Review of LIGO-India

  • Blue-ribbon panel to judge science case and to advise on possible implementation issues

  • Provided with background documents and met Oct 7 (via internet) for ~6 hours of presentation/ discussion

  • Summary finding:

    “The panel believes that the science case for LIGO-India is compelling, and reason enough to move forward in the near term with the understanding that there are a number of outstanding issues with funding, site selection, and the selection of institutional leadership, top management and technical expertise that must be resolved before making a deeper commitment.“We note that LIGO-India is the only option actively under consideration by the LIGO Laboratory.”

LIGO-India, October 2011


Where from here

Where from Here?

  • Intense evaluation by LIGO Lab over next six months

  • Group of senior LIGO Lab scientists to India in mid-October (this visit)

    • Meet potential participants and laboratory directors to assess capabilities and interest (follow-up to Rana’s visit, ‘measure first derivative’)

    • Understand project capabilities in national labs

    • Visit potential site

  • Attempt to arrange visit from vacuum system company representatives to LIGO facility

  • Continuing “training program”

    • Second Indian postdoc starts at Caltech

    • Applications for next year now open

    • Measure of momentum in forming core team

LIGO-India, October 2011


Where from here continued

Where from Here?(continued)

  • IGC2011 conference in Goa, Workshop in Pune in December--next opportunity for face-to-face meetings

    • Number of LIGO Lab and LSC attendees

    • NSF Assistant Director Ed Seidel also planning to go

  • Stay engaged in planning process in India

    • Assist with Detailed Project Report (proposal)

    • Provide information, as needed

  • Consult people with experience in collaborating with India to assess export control issues

    • Fermilab, TMT, others?

  • Planning for a final “go/no-go” visit to India in February

    • Best assessment of how far have we gotten

    • Funding status, likely lead lab, perhaps some key personnel

LIGO-India, October 2011


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