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08/31/2006
~ 2015
3 Mission specific challenges:
• Data Analysis• GRS• Interferometry
08/31/2006
08/31/2006
08/31/2006
LISA: Joint NASA/ESA project
Advanced LIGO
LIGO: NSF project
LISA vs. LIGO
EMRIs
08/31/2006
08/31/2006
Generate realistic data streams for data analysis tests
08/31/2006
Data Analysis Challenge: Can we identify all signals ?
08/31/2006
Data Analysis: Galactic Binary Routines
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08/31/2006
Data Analysis Take AwayData Analysis Take Away
Markov Chain Monte Carlo Simulations with simulated full data sets showed first successful results.
Opportunities to get involved
– Testbed for LISA Analysis
– Mock LISA Data Challenge
Lots to do
many things to contribute
… DA is progressing well
08/31/2006LISA Gravitational Reference LISA Gravitational Reference SensorsSensors
TeV Particle Astrophysics II
University of Wisconsin, Madison, August 28-31, 2006
Ke-Xun SunStanford University
For the LISA GRS Research Community
08/31/2006
GRS
Gravitational Reference Gravitational Reference Sensor (GRS) in the LISA Sensor (GRS) in the LISA
SpacecraftSpacecraft
08/31/2006
Baseline Design:Baseline Design: Two Cubic Proof Masses per Spacecraft Two Cubic Proof Masses per Spacecraft
Proof Mass
ProofMass
To and from Remote Spacecraft
Waveplate
Transmissive optics
Sensitive path
08/31/2006
LISA Test Package: LISA Test Package: ESA Space mission to test the GRSESA Space mission to test the GRS
Launch: 2009!
Performance Goal: • Acceleration < 10-14m/s-2/3 (10 times LISA)• Understand the system
08/31/2006
LISA Noise SourcesLISA Noise Sources
Additional leading term: Voltage Reference Instability
08/31/2006
Alternative Single PM DesignAlternative Single PM Design
Outgoing Laser Beam
Proof Mass
Large gap
GRS Housing
Optical ReadoutBeam
Telescope
Incoming Laser Beam
Details Shown in Figure 2
Sun, Allen, Buchman, DeBra, Byer, CQG (22) 2005 S287-S296
08/31/2006
LISA Test Package: LISA Test Package: ESA Space mission ESA Space mission to test the GRSto test the GRS
Launch: 2009Launch: 2009
Two inertial sensors,
homodyne Michelson
interferometer readout
GRS Take away:
08/31/2006
LISA InterferometryLISA Interferometry
TeV II MeetingTeV II MeetingMadison, WiMadison, Wi
August 30August 30thth, 2006, 2006
Guido Mueller University of Florida
08/31/2006
LISA Interferometry
Goal:
Measure distances with10 pm/rtHz accuracy
Basics:
Laser:• Wavelength: 1m• Power: 1 W
Telescopes:• f/1 - Cassegrain• Diameter: 40cm
Received power: ~100pW
08/31/2006
Arm lengths changeby about 50.000 kmduring 12 mts orbitor ~1 m/s. Doppler shifts (~ MHz) Unequal arm lengths (frequency noise) Telescope repointing (pointing noise)
The Orbit Problem
Very dynamic interferometer!
08/31/2006
Requirements:
• 2-20 MHz signal frequencies, changing by several MHz
• Frequency noise of 30Hz/Hz1/2 @ 1mHz
= 30000 cycl./Hz1/2 @ 1mHz
• need to be resolved with 10-5 cycles/Hz1/2 accuracy!
Dynamic Range of
9 orders of magnitude.
Solution: Tracking Filter
Phasemeter
dynamic range ~109 @ 5 mHz
Requirement
JPL-Results
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Laser Frequency (Pre-) StabilizationLaser Frequency (Pre-) Stabilization
Requirements:
Frequency noise of 30Hz/Hz1/2 @ 1mHz (for Phase meter)
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Single Common Sagnac
Round-trip arm length
1 30mHzf
Difference between arms
1 3Hzf
Sagnac effect (rotation)
1 20kHzf
Arm locking: Different potential realizations
Laser Frequency Stabilization II
08/31/2006Latest TabletopLatest TabletopResults of Arm lockingResults of Arm locking
Still a couple flaws in the experiment.
But progressing well
08/31/2006
LISA INTERFEROMETRY TAKE AWAYLISA INTERFEROMETRY TAKE AWAY
Key components perform and work at or below LISA requirements
Arm Locking: will reduce requirements on other subsystems
– Not yet demonstrated at the final level (getting close)
Main issues left for Interferometry:
– Stability of Materials and Components
– Actuators
– … standard stuff
08/31/2006
LISA SummaryLISA Summary
Will detect the big stuff: SMBH mergers
10000s galactic binaries (guaranteed)
Extreme mass ratio inspirals
Challenges:
Data analysis: Extract all the signals
GRS: How to create a freely falling mass?
– LTP: European Test mission in 2009
Interferometry:
– The main challenges are nearly solved
– Start to focus on components, bits, and pieces
LISA Launch: 2015(on NASA time scales)
