Page 1
GWADW2010 (May 20, 2010, Kyoto, Japan)
Original Picture : Sora
On behalf of DECIGO working group
Masaki Ando (Department of Physics, Kyoto University)
Space Gravitational-Wave Antenna DECIGO
Wataru Kokuyama (Department of Physics, University of Tokyo)
Page 2
GWADW2010 (May 20, 2010, Kyoto, Japan)
1. DECIGO Overview and Science
Pre-conceptual Design
2. DECIGO Pathfinder Overview and Science
Design and Status
Space Demonstration
3. Summary
Wataru
Kokuyama
Page 3
GWADW2010 (May 20, 2010, Kyoto, Japan)
1. DECIGO Overview and Science
Pre-conceptual Design
2. DECIGO Pathfinder Overview and Science
Design and Status
Space Demonstration
3. Summary
Page 4
GWADW2010 (May 20, 2010, Kyoto, Japan)
DECIGO
DECIGO
Space GW antenna (~2027)Obs. band around 0.1 Hz
10–4 10–2 100 102 104
10–26
10–24
10–22
10–20
10–18
10–16
Frequency [Hz]
Str
ain
[
1/H
z1/2 ] Terrestrial
Detectors (Ad. LIGO, LCGT, etc)
DECIGO
LISA
(Deci-hertz interferometer Gravitational wave Observatory)
‘Bridge’ the obs.gap between LISA and Terrestrial detectors
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GWADW2010 (May 20, 2010, Kyoto, Japan)
DECIGO Interferometer
Interferometer Unit: Differential FP interferometer
Laser
Photo-detector
1000kmArm cavity
Drag-free S/C
Arm
cavi
tyMirror
Baseline length: 1000 km3 S/C formation flight 3 FP interferometers Drag-free control
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GWADW2010 (May 20, 2010, Kyoto, Japan)
Targets and Science
DECIGO (1 unit)
IMBH inspiral (z~1)
Merger
Frequency [Hz]
GW
am
plitu
de [
Hz-
1/2]
10-4 10-2 100 102 104
10-24
10-22
10-20
10-18
10-16
10-26
DECIGO (Correlation)
Background
GW
(Ωgw
~ 2 x 10 -16)
NS inspiral (z~1)
Merger
3month
IMBH binary inspiralNS binary inspiralStochastic background
Galaxy formation (Massive
BH)
Cosmology (Inflation, Dark energy)
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Constraint on dark energy
GWADW2010 (May 20, 2010, Kyoto, Japan)
DECIGO will observe 104-5 NS binaries at z~1
Precise ‘clock’ at cosmological distance
Angular resolution ~ 10arcmin ( 1 detector ) ~ 10arcsec ( 3 detectors )
at z=1%1,, wwm
Determine cosmological parameters
Absolute and independent measurement
Information on acceleration of expansion of the universe
chirp waveformDistance:
Redshift: host galaxy
‘Standard Siren’
Relationship between distance and redshift
NS-NS (z ~1)
GW
DECIGO
Output
Expansion + Acceleration?
Time
Str
ai
n
Template (No Acceleration)
Real Signal ?
Phase Delay ~ 1sec (10 years)
Seto, Kawamura, Nakamura, PRL 87, 221103 (2001)
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GWADW2010 (May 20, 2010, Kyoto, Japan)
Stochastic Background GWs
Stochastic
Background GWs
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GWADW2010 (May 20, 2010, Kyoto, Japan)
1. DECIGO Overview and Science
Pre-conceptual Design
2. DECIGO Pathfinder Overview and Science
Design and Status
Space Demonstration
3. Summary
Page 10
GWADW2010 (May 20, 2010, Kyoto, Japan)
Pre-Conceptual Design
Interferometer Unit: Differential FP interferometer
Laser
Photo-detector
Arm cavity
Drag-free S/C
Arm
cavi
tyMirror
Arm length: 1000 kmFinesse: 10Mirror diameter: 1 mMirror mass: 100 kgLaser power: 10 WLaser wavelength : 532 nmS/C: drag free
3 interferometers
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Interferometer Design
GWADW2010 (May 20, 2010, Kyoto, Japan)
Transponder type vs Direct-reflection type
10–4 10–3 10–2 10–1 100 101 102 10310–25
10–24
10–23
10–22
10–21
10–20
10–19
10–18
Frequency [Hz]
Str
ain
[1
/Hz
1/2]
LCGT
LISA
DECIGO(LISA type, 5x104km)
DECIGO(FP type, 1000km)
Laser: 10W, 532nmMass: 100kgMirror: 1m dia.
WD-W
D
confusion
noise
Decisive factor: Binary confusion noise
Compare : Sensitivity curves and Expected Sciences
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Cavity and S/C control
GWADW2010 (May 20, 2010, Kyoto, Japan)
Local Sensor
Actuator
Displacement signal between the two Mirrors
Thruster Thruster
Displacement Signal between S/C and Mirror
Mirror
S/C 1
S/C 2
Fig: S. Kawamura
Cavity length change PDH error signal Mirror position (and Laser frequency)Relative motion between mirror and S/C Local sensor S/C thruster
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Requirements
GWADW2010 (May 20, 2010, Kyoto, Japan)
Sensor Noise Shot noise 3 x 10-18 m/Hz1/2 (0.1 Hz)
Acceleration Noise Force noise 4x10-17 N/Hz1/2 (0.1 Hz)
Other noises should be well below the shot noise Laser freq. noise: 1 Hz/Hz1/2 (1Hz)
Stab. Gain 105, CMRR 105
x 10 of LCGT in phase noise
x 1/50 of LISA
External force sources Fluctuation of magnetic field, electric field, gravitational field, temperature, pressure, etc.
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Orbit and Constellation
GWADW2010 (May 20, 2010, Kyoto, Japan)
Record-disk orbit around the SunRelative acc. 4x10-12 m/s2
Halo orbit around L2 (or L1)
Relative acc. 4x10-7 m/s2
(Mirror force ~10-9 N )
(Mirror force ~10-4 N )
Separated unit
Constellation
4 interferometer units
2 overlapped units Cross correlation2 separated units Angular resolution
overlapped units
Separated unit
Candidate of orbit:
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GWADW2010 (May 20, 2010, Kyoto, Japan)
2010
11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29
Mission
Objective
Space test of key tech. GW observation
Detect GW with min. spec FP between S/C
GW astronomy
Design
Single small satellite Short FP interferometer
3 S/C 1 interferometer unit
3 S/C x 3-4 units
Roadmap
Figure: S.Kawamura
DECIGO Pathfinder (DPF)
Pre-DECIGO DECIGO
R&DFabricatio
n
R&DFabricatio
n
R&DFabricatio
n
SDS-1/SWIM
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Detector
Sato (Hosei)Ueda (NAOJ)Aso (Tokyo)
Organization
PI: Kawamura (NAOJ)Deputy: Ando (Kyoto)
Executive CommitteeKawamura (NAOJ), Ando (Kyoto), Seto (Kyoto), Nakamura (Kyoto), Tsubono (Tokyo), Tanaka (Kyoto), Funaki (ISAS),
Numata (Maryland), Sato (Hosei), Kanda (Osaka city), Takashima (ISAS), Ioka (KEK), Yokoyama (Tokyo)
Pre-DECIGO
Sato (Hosei)
Satellite
Funaki (ISAS)
Science, Data
Tanaka (Kyoto)Seto (Kyoto)
Kanda (Osaka city)
DECIGO pathfinderLeader: Ando (Kyoto)
Laser
Musha (ILS)Ueda (ILS)
Drag freeMoriwaki (Tokyo)
Sakai (ISAS)
Thruster
Funaki (ISAS)
Bus
Takashima (ISAS)
Data
Kanda (Osaka
city)
Detector
Akutsu (NAOJ)Numata
(Maryland)
Mission phase
Design phase
GWADW2010 (May 20, 2010, Kyoto, Japan)
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Collaboration and support
GWADW2010 (May 20, 2010, Kyoto, Japan)
・ Supports from LISA Technical advices from LISA/LPF experiences Support Letter for DECIGO/DPF, Joint workshop (2008.11)
・ Collab. with Stanford univ. group Drag-free control of DECIGO/DPF UV LED Charge Management System for DPF
・ Collab. with NASA/GSFC Fiber Laser , started discussion
・ Collab. with JAXA navigation-control section formation flight of DECIGO, DPF drag-free control
・ Research Center for the Early Universe (RESCEU), Univ.
of Tokyo Support DECIGO as ones of main projects (2009.4-)
・ Advanced technology center ( ATC) of NAOJ Will make it a main nucleus of DPF
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GWADW2010 (May 20, 2010, Kyoto, Japan)
1. DECIGO Overview and Science
Pre-conceptual Design
2. DECIGO Pathfinder Overview and Science
Design and Status
Space Demonstration
3. Summary
Page 19
GWADW2010 (May 20, 2010, Kyoto, Japan)
2010
11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29
Mission
Objective
Space test of key tech. GW observation
Detect GW with min. spec FP between S/C
GW astronomy
Design
Single small satellite Short FP interferometer
3 S/C 1 interferometer unit
3 S/C x 3-4 units
Roadmap
Figure: S.Kawamura
DECIGO Pathfinder (DPF)
Pre-DECIGO DECIGO
R&DFabricatio
n
R&DFabricatio
n
R&DFabricatio
n
SDS-1/SWIM
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DECIGO-PF
GWADW2010 (May 20, 2010, Kyoto, Japan)
DECIGO Pathfinder (DPF)
Single satellite (Payload ~1m3 , 350kg)
Low-earth orbit (Altitude 500km, sun synchronous)
30cm FP cavity with 2 test masses Stabilized laser source Drag-free control
First milestone mission for DECIGOShrink arm cavity DECIGO 1000km DPF 30cm
DECIGO
1000km
Local Sensor
ActuatorThruster
Laser
DPF
30cm
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GWADW2010 (May 20, 2010, Kyoto, Japan)
DPF satellite
Stabilized. Laser source
Interferometer module
Satellite Bus system
Solar Paddle
MissionThruster head
On-boardComputer
Bus thruster
Satellite Bus (‘Standard bus’ system)
DPF PayloadSize : 950mm cubeWeight : 150kgPower : 130WData Rate: 800kbpsMission thruster x12
Power SupplySpW Comm.
Size : 950x950x1100mmWeight : 200kgSAP : 960W Battery: 50AHDownlink : 2MpbsDR: 1GByte3N Thrusters x 4
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DPF mission payload
GWADW2010 (May 20, 2010, Kyoto, Japan)
Fabry-Perot interferometer Finesse : 100 Length : 30cm Test mass : ~1kg Signal extraction by PDH
Drag-free control Local sensor signal Feedback to thrusters
Mission weight : ~150kgMission space : ~95 x 95 x 90 cm
Laser source Yb:YAG laser (1030nm) Power : 25mW Freq. stab. by Iodine abs. line
Thruster
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DPF Sensitivity
GWADW2010 (May 20, 2010, Kyoto, Japan)
Satellite mass : 350kg, Area: 2m2
Altitude: 500kmThruster noise: 0.1μN/Hz1/2
Laser source : 1030nm, 25mW IFO length : 30cmFinesse : 100, Mirror mass : 1kgQ-factor : 105, Substrate: TBDTemperature : 293K (Preliminary
parameters)
10–2 10–1 100 101 10210–18
10–17
10–16
10–15
10–14
10–13
10–12
10–11
10–18
10–17
10–16
10–15
10–14
10–13
10–12
No
ise
leve
l
[1/H
z1/2
]
Frequency [Hz]
Shot noise
Mirror thermal
Laser Radiation
Laser: 1030nm, 25mWFinesse: 100Mirror mass: 1kgQ–value of a mirror: 106
Cavity length: 30cm
pressure noiseThruster noise
PM acceleration Noise
Geog
ravity Laser Frequencynoise
Dis
pla
cem
ent
No
ise
[m
/Hz1
/2]
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GWADW2010 (May 20, 2010, Kyoto, Japan)
DPF sensitivity
10–4 10–2 100 102 104
10–26
10–24
10–22
10–20
10–18
10–16
Frequency [Hz]
Str
ain
[
1/H
z1/2 ]
DECIGO
LCGT
Core-collapseSupernovae
NS binary inspiral
ScoX-1 (1yr)
Pulsar (1yr)
Massive BH inspirals
Galaxybinaries
Gravity-gradient noise (Terrestrial detectors)
DPF limit
Background GWsfrom early universe (Wgw=10-14)
DPF sensitivity h ~ 2x10-15 Hz1/2 (x10 of quantum noises)
Foreground GWs
LISA
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GWADW2010 (May 20, 2010, Kyoto, Japan)
103 104 105 10610–1
100
101
102
Ob
serv
able
Ran
ge
Mass [Msolar]
[kp
c, S
NR
=5
]
Galactic
BH QNMBH In
spiral
Including Merger
Center
GW target of DPF
Observable range covers our Galaxy (SNR~5 )
BH QNM
h ~ 10-15 , f ~ 0.3 Hz Distance 1Mpc, m = 105
Msun
IMBH inspiral and merger
Obs. Duration (~1000sec)
h ~ 10-15 , f ~ 4 Hz Distance 10kpc, m = 103
Msun
KAGAYA
Blackholes events in our galaxy
Hard to access by others Original observation
(By K.Yagi)
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Gravity of the Earth
GWADW2010 (May 20, 2010, Kyoto, Japan)
Measure gravity field of the Earth from Satellite Orbits, and gravity-gradiometer
Determine global gravity field Density distributionMonitor of change in time Ground water motion Strains in crusts by earthquakes and volcanoes
GPS satellite
By Araya and Fukuda
Observation Gap between GRACE and GRACE-FO (2012-16) DPF contribution in international network
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GWADW2010 (May 20, 2010, Kyoto, Japan)
1. DECIGO Overview and Science
Pre-conceptual Design
2. DECIGO Pathfinder Overview and Science
Design and Status
Space Demonstration
3. Summary
Page 28
Interferometer Module
GWADW2010 (May 20, 2010, Kyoto, Japan)
Interferometer Module : Test mass + IFO
NAOJ, U-Tokyo
Interferometer Module
Interferometer GW, Gravity observation
Test-mass module Gravity reference
・ 30cm IFO BBM ・Packaging Digital control ・Monolithic Opt.
Laser sensor Small MI
Hosei, NAOJ, Ochanomizu, Stanford
・ BBM of Module, Sensor, Actuator, Clump/Release・ μ-Grav. Exp.
ERI, U-Tokyo
・ BBM test・ Sensitivity meas.
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Stabilized Laser Module
GWADW2010 (May 20, 2010, Kyoto, Japan)
Stabilized Laser : Laser source + Stabilization system
UEC, NICT
StabilizedLaser Module
I2 absorption line
Frequency reference
UEC, NASA/GSFC
Yb:YAG (NPRO or Fiber laser) Laser source ・ BBM development
・ BBM development・ Stability meas.
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Attitude and Drag-free control
GWADW2010 (May 20, 2010, Kyoto, Japan)
Attitude and Drag-free control : Structure, Thrusters, Control
JAXA, NDAJ, Tokai-U
Low-noise Thruster
Low-noise Thruster
U-Tokyo, JAXA
Structure, thermal stability
Mass balance
・ Passive attitude stability・ Drag-free control
Actuators for satellite control
・ BBM and system design
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Signal processing and Control
GWADW2010 (May 20, 2010, Kyoto, Japan)
Signal Processing and Control : SpaceWire-based system
Signal processor
JAXA, U-Tokyo, Kyoto
SpC2 + SpW system Signal processing and install. ctrl
Test-mass control
Photo by JAXA
SDS-1 (Jan. 2009)
SWIMmnSpC2
SWIMmn demonstration Test mass control in orbit
Space demonstration bySDS-1/SWIM
Satellite Bus
JAXA, U-Tokyo, Kyoto
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GWADW2010 (May 20, 2010, Kyoto, Japan)
1. DECIGO Overview and Science
Pre-conceptual Design
2. DECIGO Pathfinder Overview and Science
Design and Status
Space Demonstration
3. Summary
Page 33
GWADW2010 (May 20, 2010, Kyoto, Japan)
1st mission (2012): SPRINT-A/EXCEED2nd mission (~2013/14) : ERG
3rd mission (~2015/16) : TBD
DPF mission status
DPF : One of the candidate of JAXA’s small satellite series
At least 3 satellite in 5 years withStandard Bus + M-V follow-on rocket
DPF survived until final two
SPRINT-A /EXCEED UV telescope mission
Next-generationSolid rocket booster (M-V FO) Fig. by JAXA
DPF is one of the strongest candidates of the 3rd mission
Page 34
GWADW2010 (May 20, 2010, Kyoto, Japan)
1. DECIGO Overview and Science
Pre-conceptual Design
2. DECIGO Pathfinder Overview and Science
Design and Status
Space Demonstration
3. Summary
Page 35
Summary
GWADW2010 (May 20, 2010, Kyoto, Japan)
DECIGO : Fruitful Sciences
Very beginning of the UniverseDark energyGalaxy formation
DECIGO Pathfinder
Important milestone for DECIGOStrong candidate of JAXA’s satellite seriesSWIM – under operation in orbit first precursor to space!
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GWADW2010 (May 20, 2010, Kyoto, Japan)
End
Original Picture : Sora