1. Advanced Detector Status Report and Future Scenarios
Giles Hammond, University of Glasgow
on behalf of the LIGO Scientific Collaboration and the VIRGO Collaboration
3rd October 2012
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2. Overview of the presentation
Worldwide network of detectors
Astrophysics with Advanced detectors
Overview of the ongoing detector upgrades
GEO-HF
Advanced LIGO (aLIGO)
Advanced VIRGO (AdV)
Incremental upgrades to the Advanced detectors
Summary and future prospects

3. Worldwide Detector Network
GEO
LIGO Hanford (LHO)
LIGO Livingston (LLO)
VIRGO
ACIGA
KAGRA

4. Astrophysics with Advanced Detectors
The worldwide network is being upgraded to 2nd generation or “Advanced” status
A network allows source location for follow up observations =>Multimessenger astronomy
The advanced detectors will provide the first detections of gravitational waves and open up a new, non-electromagnetic, window on the universe
Multimessenger astronomy (e.g. EM/neutrino observation) will increase detection confidence and provide complementary information
Expected event rates of several ten’s of neutron stars coalescences per year
INDIA/KAGRA/LIGO/VIRGO
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5. Astrophysics with Advanced Detectors
Fundamental test of general relativity=> measure the “speed of gravity” and the polarisation of gravitational waves
Confirm or rule out that the fireballs of gamma-ray burst events are powered by merging neutron star binaries
Detect, for the first time, binary black holes and possibly provide the clue to the missing population of intermediate-mass black holes
Measure the equation-of-state of ultra dense matter in neutron star cores and thereby help understand extremes of nuclear physics
Accurately measure the masses and spins of a number of neutron stars and black holes
Provide new tests of strong field gravity
Accurately measure the Hubble constant

6. Worldwide Detector Network >2010
LIGO India
aLIGO
eLIGO
LIGO
Advanced LIGO and Advanced VIRGO will result in a 10 distance increase => 1000 increase in volume
GEO-HF features a high frequency upgrade (>500Hz)
KAGRA (LCGT) will be the first cryogenic detectors
LIGO India (2018) will significantly improve source location

7. Laser Interferometric Detectors
seismic noise
mirror thermal noise
shot noise
Need to measure length changes 10-18m over 4km baselines
Suspended optics (to reduce seismic noise)
Ultra-high purity materials (to reduce thermal noise)
High power solid state lasers (to reduce shot noise)
Technologies required =>

8. GEO monolithic suspension
GEO-HF
GEO600: the first detector to pioneer monolithic fused silica suspensions and advanced interferometric techniques (signal recycling)
GEO-HF upgrade will bridge the gap until longer baseline detectors will reach better sensitivities in the kHz range => ensuring continued network operation
Pioneering techniques such as squeezed light
Squeezed light
30 W laser
Improved thermal
compensation
MSR
GEO monolithic suspension
Class. Quantum Grav., 29, ,2012
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9. GEO-HF Hardware GEO squeezed light source Squeezed light (laser
appears 1.5x more powerful)
Light entering interferometer
through the output port
Improved thermal compensation at beamsplitter
LIGO G , H. Wittel, PhD thesis

10. GEO-HF Hardware GEO squeezed light source Squeezed light (laser
appears 1.5x more powerful)
Light entering interferometer
through the output port
Improved thermal compensation at beamsplitter
LIGO G , H. Wittel, PhD thesis

11. GEO-HF Hardware Squeezed light (laser appears 1.5x more powerful)
Light entering interferometer
through the output port
Nature Physics, Vol. 7, p. 962–965, 2011

12. Power and Signal recycling Cavities
Advanced LIGO (aLIGO)
Dual (Signal and Power) recycled Fabry-Perot interferometer
40kg test mass
Seismic isolation
LIGO lab
aLIGO ring heater
180 W
laser
4km
Suspension
Active seismic isolation
QUAD suspension
Fused silica lower stage
Thermal compensation (ring
heater and CO2 laser)
Power and Signal recycling Cavities
LIGO M060056

13. Active seismic isolation
aLIGO Hardware
Active seismic isolation
10 isolation at 0.16mHz
1 000 isolation at 10Hz
Actuate b k
180W aLIGO laser (97% in TEM00)
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14. aLIGO Hardware Initial LIGO (10.7kg) aLIGO lower glass stage (40kg)
Hydroxide catalysis bonding
Initial LIGO (10.7kg)
aLIGO lower glass stage (40kg)
Ultra-low loss final stage for
lowering thermal noise
test mass (34cm)
CO2 laser welding
Mirrors are suspended from 7 isolation stages:
1 external hydraulic actuator
2 active isolation
QUAD (x4) pendulum
Class. Quantum Grav., 29, , 2012
Rev. Sci Instrum., 82, , 2011
Fibre pulling with a CO2 laser

15. aLIGO Installation Seismic isolation system Cartridge installation
at LIGO Hanford
Chamber cleaning
QUAD Suspension
at LIGO Hanford
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16. aLIGO design curves (LIGO G1200982)
aLIGO Timeline
aLIGO design curves (LIGO G )
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There is significant ongoing activity at the Hanford and Livingston sites
Currently conducting:
a 4km long single arm at LHO (Hanford)
a vertex test at LLO (Livingston) comprising everything except end test masses
Installation complete date: LLO (May 2013) and LHO (September 2013)
Acceptance (2-hour lock) date: LLO (April 2014) and LHO (May 2014)

17. aLIGO Timeline aLIGO layout
LIGO M060056
aLIGO layout
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There is significant ongoing activity at the Hanford and Livingston sites
Currently conducting:
a 4km long single arm at LHO (Hanford)
a vertex test at LLO (Livingston) comprising everything except end test masses
Installation complete date: LLO (May 2013) and LHO (September 2013)
Acceptance (2-hour lock) date: LLO (April 2014) and LHO (May 2014)

18. Power and Signal recycling Cavities
Advanced VIRGO
Dual (Signal and Power) recycled Fabry-Perot interferometer
40 kg test masses
VIRGO test mass
Bizouard, MG 11, Berlin
2100 W
laser
Vacuum system
Multi-stage nested pendulums for low seismic attenuation
Fused silica lower stage
Thermal compensation (ring heater and CO2 laser)
Power and Signal recycling Cavities
(VIR–0128A–12) Fig 1.1

19. Advanced VIRGO Hardware
100W rod amplifiers under test (NICE)
20kg mirror for VIRGO (AdV is twice as thick)
Fused silica fibre pulling
VIR-0312A-12/LIGO-G
Fused silica fibre puller/welder

20. Advanced VIRGO Hardware
Compact 2-stage isolator for auxiliary optics
aVIRGO mirror test stand
6 stage “super attenuator”
VIR-0312A-12/LIGO-G

21. Advanced VIRGO Timeline
Flaminio, MG12
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The Advanced Virgo Technical Design Report was released in April 2012
There is significant ongoing activity at the Cascina site
Installation/integration will be completed in the first half of 2015
Commissioning will begin before the end of the installation
laser and input optics
3km cavity

22. Upgrades to Advanced detectors
In 2011 the LIGO Scientific Collaboration initiated a study of upgrade scenarios:
What R&D is needed over the next few years?
When do we need to be ready for the upgrades
Can we do the upgrades in an incremental way?
How much improvement is possible?
Three design teams (Red/Green/Blue) working on:
Room temperature upgrades
Cryogenic upgrades
Heavier (150kg) test masses
New optical coatings
Low frequency subtraction of gravity
Alternative operating wavelengths (1064nm vs 1550nm)
Combined low/high frequency cold/warm interferometers: Xylophone configuration

23. Upgrades to Advanced detectors
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24. Upgrades to Advanced detectors
LIGO-G
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For more details on KAGRA and ET please see the talks:
12:10-12:40: KAGRA project: status report (T. Kajita)
14:00-14:30 Einstein Telescope (ET) project (H. Lueck)
14:30-15:00 KAGRA and ET (K. Somiya)
Workpackage meetings 3rd/4th October

25. Summary
There is a significant worldwide effort to install and commission the hardware necessary for Advanced gravitational wave detectors
Fused silica suspension, active seismic isolation and squeezed light are being used to improve sensitivity by a factor of 10 over the observing band of 10Hz-10kHz
Advanced network will be operational in 2014/2015
Observing schedule for LSC detectors:
2015: 3 month run with LLO/LHO at 60Mpc range. Advanced VIRGO in commissioning at 40Mpc with the opportunity to join the data run
: 6 month run with LLO/LHO at 100Mpc and Advanced VIRGO at 40Mpc
: 6 month run with LLO/LHO at 140Mpc and Advanced VIRGO at 70Mpc
2019+: LLO/LHO at full sensitivity (200Mpc) and Advanced VIRGO at 100Mpc
2022+: LLO/LHO, Advanced VIRGO and LIGO India at full sensitivity
From 2015 there is the opportunity for the Advanced detectors to open the gravitational wave window on the Universe.
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