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International Conference on Topics in Astroparticle and Underground Physics (Sept. 11, 2007, Sendai, Japan )
DECIGO PathfinderDECIGO Pathfinder
Masaki Ando Masaki Ando (Department of Physics, The University of Tokyo)(Department of Physics, The University of Tokyo)
and DECIGO Pathfinder working and DECIGO Pathfinder working GroupGroup
International Conference on Topics in Astroparticle and Underground Physics (Sept. 11, 2007, Sendai, Japan ) 2
Introduction (1)Introduction (1)
DECIGO roadmap
LISALPF
Ad. LIGOLCGT
International Conference on Topics in Astroparticle and Underground Physics (Sept. 11, 2007, Sendai, Japan ) 3
DECIGO-PF (1)DECIGO-PF (1)
DECIGO Pathfinder (DPF)
DECIGO-PF One small satellite (Weight: ~200-300kg, Orbit: around the earth) 10cm Fabry-Perot cavity formed by free masses Stabilized laser source Drag-free control system
Local Sensor
Actuator
Thruster
Gravitational-wave observation (5) Observation for low-frequency (0.1-1Hz) GWs Mid.-scale BHs at the Galactic center
Test and demonstration for DECIGO (1) Drag-free control system (2) Laser source and its stabilization system (3) Control of Fabry-Perot interferometer (4) Launch-lock system
International Conference on Topics in Astroparticle and Underground Physics (Sept. 11, 2007, Sendai, Japan ) 4
DECIGO-PF (2)DECIGO-PF (2)
DPF diagram
Fabry-Perot interferometer Finesse : 100 Length : 10cm Test mass : 1kg Signal extraction by PDH
Laser source Nd:YAG laser (1064nm) Power : 25mW Freq. stab. by reference cavity
Drag-free control Local sensor signal Feedback to thrusters/wheels
Mission weight : ~100kgMission space : ~90 x 90 x 90 cm
International Conference on Topics in Astroparticle and Underground Physics (Sept. 11, 2007, Sendai, Japan ) 5
DECIGO-PF (3)DECIGO-PF (3)
DPF sensitivity
Satellite mass : 100kg, Area: 1m2
Altitude: 750kmThruster noise: 0.1μN/Hz1/2
Laser source : 1064nm, 25mW IFO length : 10cmFinesse : 100, Mirror mass : 1kgQ-factor : 105, Substrate: Fused SilicaTemperature : 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
10–19
10–18
10–17
10–16
10–15
10–14
10–13
10–12
No
ise
lev
el
[1
/Hz1/
2 ]
Frequency [Hz]
Shot noise
Mirror thermal
Laser Radiation
Laser: 1064nm, 25mWFinesse: 100Mirror mass: 1kgQ–value of a mirror: 10 6
Cavity length: 10cm
pressure noiseThruster noise
PM acceleration Noise
Geogravity
Laser Frequencynoise
Dis
pla
ce
me
nt
No
ise
[m
/Hz1/
2 ]
International Conference on Topics in Astroparticle and Underground Physics (Sept. 11, 2007, Sendai, Japan ) 6
DECIGO-PF (4)DECIGO-PF (4)
DPF orbit
DP
F
Selection of DPF orbit Launch chance (Cost, Launch window) Operation (Power supply, Telemetry) Stability, NoisesLow-earth orbit
Altitude 750km Polar sun synchronous orbit
750km
No eclipse Full-time operationHigher altitude will be desirable to reduce the effect of the earth (Earth’s gravity, terrestrial magnetism, residual atmosphere)Depends on launch chance
Earth
Sun
International Conference on Topics in Astroparticle and Underground Physics (Sept. 11, 2007, Sendai, Japan ) 7
DECIGO-PF (5)DECIGO-PF (5)
Gravity-gradient noise Global gravity field model Public data obtained by GRACE Up to 150th-order in spherical harmonicsSatellite velocity of 5km/sec Estimate the noise spectrum Assume 2% vertical-horizontal coupling
Cut-off at 0.03Hz: originates in the model resolution Unknown at higher frequencyThis will not be a problem: higher-order contribution will be negligible order of ~(Re/r) n
Observe gravity field with higher resolution?
10–2 10–1 100 101 10210–18
10–17
10–16
10–15
10–14
10–13
10–12
10–11
Ac
ce
lera
tio
n N
ois
e [
m/s
2 /Hz1/
2]
Frequency [Hz]
Shot noise
Mirror th
ermal
Laser Radiationpressure noise
Radiation Pressure
of the Sun
PM acceleration Noise
Earth's Tidal force
DPF total
International Conference on Topics in Astroparticle and Underground Physics (Sept. 11, 2007, Sendai, Japan ) 8
DECIGO-PF (6)DECIGO-PF (6)
Geomagnetic noise
Fluctuation in geomagnetic field Public data at Esashi observatory 1 sample/min data Extrapolate for higher frequency
Two effect by geomagnetic field: Satellite motion in magnetic field Fluctuation in geomagnetic field
10–3 10–2 10–1 10010–6
10–4
10–2
100
102
104
Mag
net
ic n
ois
e [
nT/
Hz1
/2]
Frequency [Hz]
(N–S Direction)
(Vertical Direction)
Geomagnetic FieldFluctuation
S/C motion
S/C Motion
Geomagnetic field model IGRF-10 model (10th generation of International
Geomagnetic Reference Field) Altitude 750km Satellite velocity of 5km/sec
Satellite self-field
Effect of geomagnetic field: smaller than satellite self-field ~10-7 T noise level ~ 1.5 x 10-16 m/s2/Hz1/2
10–2 10–1 100 101 10210–18
10–17
10–16
10–15
10–14
10–13
10–12
10–11
Ac
ce
lera
tio
n N
ois
e [
m/s
2 /Hz1/
2]
Frequency [Hz]
Shot noise
Mirror th
ermal
Laser Radiationpressure noise
Radiation Pressure
of the Sun
PM acceleration Noise
Earth's Tidal force
DPF total
Magnetic-field noise
International Conference on Topics in Astroparticle and Underground Physics (Sept. 11, 2007, Sendai, Japan ) 9
DECIGO-PF (7)DECIGO-PF (7)
Survey of noise sources
Residual Gas
Thermal radiation
Magnetic field
Laser freq. noise
Force Acceleration Acceleration noise Displacement noise
International Conference on Topics in Astroparticle and Underground Physics (Sept. 11, 2007, Sendai, Japan ) 10
10–4 10–2 100 102 104
10–26
10–24
10–22
10–20
10–18
10–16
Frequency [Hz]
Str
ain
[1
/Hz1/
2]
DECIGO-PF (8)DECIGO-PF (8)
Comparison with other detectors
LCGT DECIGO
Galactic binaryForeground noise
Core-collapse super nova
NS inspiral
Inspiral ofMassive BH
Galactic binary
ScoX-1 (1yr)Pulsar
(1yr)
LISA
Gravity-gradient noise for terrestrial detectors
DPF limit
Only a little observation data at low-frequency band Doppler tracking: h ~10-15 (10-4-10-2 Hz) Pulsar timing: h ~10-14 (10-8 Hz)
GWs from Early universe (gw=10-14)
International Conference on Topics in Astroparticle and Underground Physics (Sept. 11, 2007, Sendai, Japan ) 11
DECIGO-PF (9)DECIGO-PF (9)
DPF targetsQuasi-nomal mode oscillation of massive BH
Binary inspiral of mid.-scale BHs
10–2 10–1 100 101 10210–17
10–16
10–15
10–14
10–13
10–12
GW
ch
arac
teri
stic
am
plit
ud
e
Frequency [Hz]
Dopplar105Mo
DPF
(Ob
s.
ba
nd
= C
en
ter
fre
qu
en
cy
)
tracking
BH QNM(1Mpc)
BH chirp(103Mo, 10kpc)
DPFFundamental noise
106Mo
104Mo
Estimated noises
103 104 105 10610–1
100
101
102
Ob
serv
able
Ran
ge
Mass [Msolar]
[kp
c, S
NR
=5
]
Galactic Center
BH QNM
BH Inspiral
Events at Galactic center will be detectable with SNR~5
h ~ 10-15 , f ~ 0.3 Hz Distance 1Mpc, m = 105 Msun
h ~ 10-15 , f ~ 4 Hz Distance 10kpc, m = 103 Msun
International Conference on Topics in Astroparticle and Underground Physics (Sept. 11, 2007, Sendai, Japan ) 12
DPF status (1)DPF status (1)
Brief history
2004 December Call for suggestions of small satellite mission by JAXA2005 January Submit a proposal of small GW detector mission ~30 missions were submitted2006 October Call for proposals of small satellite mission by JAXA2006 November Submit a proposal of GW-detector satellite as DECIGO pathfinder (DPF) 16 missions were accepted as working groups (10 science, 6 engineering missions), including DPF2007 April Review meeting for these missions2007 August DPF has been selected as one of 5 Pre-Phase-A missions R&D costs have been funded
International Conference on Topics in Astroparticle and Underground Physics (Sept. 11, 2007, Sendai, Japan ) 13
DPF status (2)DPF status (2)
DPF status
JAXA is planning to launch 3 small satellite by the year 2013 using next-generation solid rocket booster under developmentReduce time and cost by means of ‘Standard bus system’ Preliminary parameters Bus weight : ~ 200kg, Bus power : ~ 900W Downlink ~ 4Mbps, Data storage ~ 1GByte 3-axes angular control
1st mission (2011) has been decided to be TOPS (Space telescope mission for planet observation)
2nd and 3rd mission will be selected by 2009 March
Candidate missions DPF: GW observation DIOS: X-ray telescope for dark baryon investigation ERG: Plasma and particle detector for geo-space investigation Satellite for Magnet-plasma sail technology demonstration
International Conference on Topics in Astroparticle and Underground Physics (Sept. 11, 2007, Sendai, Japan ) 14
DPF status (3)DPF status (3)
R&D plan for DPF
Laser frequency stabilizationMirror and its housing (local sensor, actuator, launch-lock
system)Micro thrusterDrag-free control simulationDetailed design and noise investigation
(Under discussion)
Required to submit Phase-A proposal by 2009 MarchR&D for core technologies
Target: launch in 2012 or 2013 as 2nd or 3rd standard small satellite of JAXA
International Conference on Topics in Astroparticle and Underground Physics (Sept. 11, 2007, Sendai, Japan ) 15
SummarySummary
One small satellite (Weight: ~200-300kg, Orbit: around the earth) 10cm Fabry-Perot cavity formed by free masses Stabilized laser source Drag-free control system
Local Sensor
Actuator
Thruster
Gravitational-wave observationTest and demonstration for DECIGO
DECIGO pathfinder: First demonstration satellite for DECIGO
Selected and funded as one of the candidates of JAXA’s small satellite missions Hoping to be launched in 2012 - 2013
0.1Hz-1Hz bandBH QNM and Mid.-BH inspiral at Galactic
center
International Conference on Topics in Astroparticle and Underground Physics (Sept. 11, 2007, Sendai, Japan ) 16
TopicsTopics
Steps for DPFSmall module to be launched in 2008
SDS-I : Small (~100kg) satellite for demonstration of space technologies To be launched in 2008 summer by H-IIA as piggy-back satellite of GOSATSWIM: very small GW detector module will be included in SWIM (SpaceWire Interface demonstration Module)
Small test-mass moduleSmall test-mass module
Test mass
Photo sensor
Coil-magnet actuator
Free-falling experiment using balloon
BOV 2.5 : Free-falling vehicle from large balloon ~30 sec free-falling streach from 40km altitude Drag-free control system using gas-jet thrustersPrototype of SWIM is included in BOV
Experiment module Diameter ~ 28cm
International Conference on Topics in Astroparticle and Underground Physics (Sept. 11, 2007, Sendai, Japan ) 17
EndEnd
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