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Advanced LIGO will have more than a factor of 10 greater sensitivity
than initial LIGO. Since the volume of space that the instrument can see
grows as the cube of the distance, this means that the event rates will
be more than 1,000 times greater. Advanced LIGO will equal the 1-yr
integrated observation time of initial LIGO in roughly 3 hours.



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Advanced LIGO
As the initial LIGO interferometers start to put new limits on
gravitational wave signals, the LIGO Lab, the LIGO Scientific
Collaboration, and international partners are building Advanced LIGO to
improve the sensitivity by more than a factor of 10 beyond initial LIGO.
This new detector, to be installed at the LIGO Observatories, will
replace the present detector, and will transform gravitational wave
science into a real observational tool. It is anticipated that this new
instrument will see gravitational wave sources weekly, with excellent
signal strengths, allowing details of the waveforms to be read off and
compared with theories of neutron stars, black holes, and other highly
relativistic objects. The improvement of sensitivity will allow the
one-year observation time of initial LIGO to be equaled in just several
hours.
The change of more than a factor of 10 in sensitivity comes also with a
change in the bandwidth of high sensitivity, and the ability to tune the
instrument for specific astrophysical sources. This will allow Advanced
LIGO to look at the inspiral, coalescence, and ringdown of pairs of black
holes up to 50 solar masses, and to pinpoint periodic signals from the
many known pulsars which radiate in the range from 500-1000 Hertz. Recent
results from the WMAP satellite have shown the rich information that
comes from looking at the photon, or infrared cosmic background, which
comes from some 400,000 years after the Big Bang. Advanced LIGO can be
optimized for the search for the gravitational cosmic background -
allowing tests of theories for the development of the universe at only
10-35 seconds after the Big Bang.
The LIGO Observatories were planned at the outset to support the
continuing development of this new science, and the significant
infrastructure of buildings and vacuum systems is left unchanged. The new
instruments take advantage of research that has taken place since the
initial instruments were designed in the mid-1990^Òs, and call for
changes in the lasers (180 W highly-stabilized systems), optics (40 kg
fused silica test masses), seismic isolation systems (using inertial
sensing and feedback), and the way in which the microscopic motion (some
10-20 meters) of the test masses is detected. Several of these
technologies are significant advances in their fields, and have promise
for application in a wide range of precision measurement,
state-of-the-art optics, and controls systems. A program of testing and
practice installation will allow the new detectors to be brought on-line
with a minimum of interruption in observation.
The design of the instrument has come from scientists throughout the
60-institution, 700-person LIGO Scientific Collaboration, an
international group which carries out both instrument development and
scientific data analysis. In the US, these efforts (and in particular the
LIGO Laboratory) are supported by the National Science Foundation. In
addition, several of our international partners - the United
Kingdom-German project GEO600 and the Australian gravitational-wave
consortium ACIGA are making significant material participation to
Advanced LIGO.
After thorough peer review, Advanced LIGO proposal was approved by the
National Science Board in October, 2004, and the project started with
funding in April 2008. We plan to start observations in 2015. The science
that follows may well revolutionize our view of the Universe.
More detailed information can be found here.
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