Japanese Gravitational Wave Detectors:

LCGT and DECIGO

Frontiers in Optics 2009Laser Science XXV

Oct. 13, 2009San Jose, USA

Seiji Kawamura (NAOJ),LCGT Collaboration, DECIGO Working Group

Sora

Outline Roadmap Ground-based detector

TAMA300CLIOLCGT

Space antennaDECIGODECIGO Pathfinder

Roadmap ofthe Japanese GW detection

2000

01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Ground-

based

▲ ▲ ▲

Space

▲ ▲ ▲

TAMA

CLIOLCGT

DECIGO Pathfinder Pre-DECIGO DECIGO

R&D

Advanced LCGT

Ground-based Detector TAMA300 CLIO LCGT

5

TAMA300 300 m power-recycled FP Michelson interferometer

located on the NAOJ campus in Tokyo

Project started 1995 Best sensitivity in world

2000-2002

6

New Seismic Attenuation SystemJoint development with LIGO (Riccardo DeSalvo et al.) based on earlier Virgo concept

Photo: Nikon

100 m cryogenic prototype

Differential FP interferometer

located in the Kamioka mine in Gifu

TAMA300

CLIO

Ground motion in Kamioka mine

Sensitivity of CLIO

Frequency

Dis

plac

emen

t noi

se 1

/√H

z

Mirror suspension thermal noise--inversely proportional to f 2.5

Mirror thermal noise

Thermal noise limit by eddy current damping between actuator magnets and metal solenoid holder--inversely proportional to f 2

3km Underground at Kamioka Cryogenic mirrors

LCGT

Goal Sensitivity of LCGT

Detection range of LCGT

LCGT in network

L/H+L/L+V 50% L/H+L/L+V+LCGT 50%

B. F. Schutz

LIGO(H)+LIGO(L)+Virgo

Coverage at 0.5 M.S.: 72% 3 detector duty cycle: 51%

LIGO(H)+LIGO(L)+Virgo+LCGT Max sensitivity (M.S.): +13% Coverage at 0.5 M.S.: 100% 3 detector duty cycle: 82%

OrganizationLCGT: hosted by ICRR under MOU with NAOJ and KEK. LCGT collaboration: 118 members (92 domestic, 26 oversea members)

Funding Status Proposal for the 2010 start did not go

through. We will submit a proposal for the 2011

start. Application for the stimulus fund was

turned down.

What is DECIGO?Deci-hertz Interferometer Gravitational Wave Observatory(Kawamura, et al., CQG 23 (2006) S125-S131) Bridges the gap between LISA and terrestrial detectors Low confusion noise -> Extremely high sensitivity

10-18

10-24

10-22

10-20

10-4 10410210010-2

Frequency [Hz]

Stra

in [H

z-1/2]

LISA

DECIGO

Terrestrial detectors (e.g. LCGT)

Confusion Noise

moved above

LISA band To be movedinto TD band

Pre-conceptual designDifferential FP interferometer

Arm length: 1000 kmMirror diameter: 1 mLaser wavelength ： 0.532 mFinesse: 10Laser power: 10 WMirror mass: 100 kgS/C: drag free3 interferometers

LaserPhoto-detector

Arm cavity

Drag-free S/C

Arm cavity

Mirror

Why FP cavity?

Frequency

Stra

in

Radiation pressure

noise f -2

Shot noiseShot n

oise f1

Transponder type(e.g. LISA)

Shot noise

Shortenarm length

Shot noise

f1

Radiation pressure

noise f -2

Transponder type(e.g. LISA) Shorten

arm length Implement FP cavity

Implement FP cavity

FP cavity type Better best- sensitivity

Drag free and FP cavity: compatible?

Mirror

S/C IS/C II

FP cavity and drag free : compatible?

Local sensor

ThrusterThruster

Mirror

Relative position between mirror

and S/C

S/C II S/C I

Drag free and FP cavity: compatible?

Local sensor

ThrusterThruster

Mirror

Relative position between mirror

and S/C

Actuator

Interferometer output (GW signal)

S/C II S/C I

No signalmixture

Orbit and constellation (preliminary)

Sun

Earth

Record disk

Increase angular resolution

Correlation for stochastic background

Inflation

Formation of super-

massive BH

Verification of inflation

Science by DECIGO

Frequency [Hz]

Correlation(3 years)

Stra

in [H

z-1/2]

10-3 10-2 10-1 1 10 102 103

10-19

10-20

10-21

10-22

10-23

10-24

10-25

10-26

(1000 M◎ z=1)

BH binaryCoalescence

5 years

NS binary (z=1)

Coalescence

3 months

Acceleration of Universe

Dark energy

Radiation pressure noise

Shot noise

1 unit

Mini-black hole

Dark matter

Brans Dickeparameter

Requirements Force noise of DECIGO should be 50

times more stringent than LISAAcceleration noise in terms of h: comparableDistance: 1/5000Mass: 100

Sensor noise of DECIGO should be10 times looser than LCGTSensor noise in terms of h: comparable,Storage time: 10

Roadmap2009 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

Mission

Objectives

Test of key technologiesDetection of GW w/ minimum spec.Test FP cavity between S/C

Full GW astronomy

Scope

1 S/C1 arm

3 S/C1 interferometer

3 S/C,3 interferometer3 or 4 units

DICIGO Pathfinder (DPF) Pre-DECIGO

DECIGO

R&DFabrication

R&DFabrication

R&DFabrication

SWIM

DEDCIGO Pathfinder (DPF)

Local Sensor

Actuator

Thruster

Single satellite Earth orbit Altitude: 500km Sun synchronous

Arm length: 1000 kmArm length: 30 cm

conceptual design and objectives of DPF

ThrusterLocal

Sensor

Floating mirrorIodine cell

LaserActuator

Test of drag-free system

Test of locking system in space

Test of laser in space

Test of frequency stabilization

system in space

Observation of GW at 0.1 – 1 Hz

Payload and standard bus

Stabilized. Laser source

Interferometer module

Satellite Bus system

Solar Paddle

MissionThruster head

On-boardComputer

Bus thruster

Mast structure

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

Goal sensitivity of DPF

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

Noi

se le

vel

[1/H

z1/2 ]

Frequency [Hz]

Shot noiseMirror thermal

Laser Radiation

Laser: 1064nm, 25mWFinesse: 100Mirror mass: 1kgQ–value of a mirror: 106

Cavity length: 10cm

pressure noise

Thruster noise

PM acceleration Noise

Geogravity Laser Frequencynoise

Dis

plac

emen

t Noi

se

[m/H

z1/2 ]

Detection range

103 104 105 10610–1

100

101

102

Obs

erva

ble

Ran

ge

Mass [Msolar]

[kpc

, SNR

=5]

Galactic Center

BH QNMBH Inspiral

R&D for Subsystems

Frequency-stabilized laser

ThrusterInterferometric sensor

Drag-freemodel

Electrostatic sensor/actuator

Test mass module

SWIM launch and operationTiny GW detector module Launched in Jan. 23, 2009

Test mass

Photo sensor

Coil

TAM: Torsion Antenna Module with free-falling test mass (Size : 80mm cube, Weight : ~500g)

Reflective-type optical displacement sensorSeparation to mass ~1mmSensitivity ~ 10-9 m/Hz1/2

6 PSs to monitor mass motion

~47g Aluminum, Surface polishedSmall magnets for position control

Photo： JAXA

In-orbit operation

Interim organizationPI: Kawamura (NAOJ)Deputy: Ando (Tokyo)

Executive CommitteeKawamura (NAOJ), Ando (Tokyo), Seto (NAOJ), Nakamura (Kyoto),

Tsubono (Tokyo), Tanaka (Kyoto), Funaki (ISAS), Numata (Maryland), Sato (Hosei), Kanda (Osaka city), Takashima (ISAS), Ioka (Kyoto)

Pre-DECIGO

Sato (Hosei)

Satellite

Funaki (ISAS)

Science, Data

Tanaka (Kyoto)Seto (NAOJ)

Kanda (Osaka city)

DECIGO pathfinderLeader: Ando (Tokyo)

Deputy: Takashima (ISAS)

Detector

Ueda (NAOJ)

Housing

Sato (Hosei)

Laser

Ueda (ILS)Musya (ILS)

Drag free

Moriwaki (Tokyo)Sakai (ISAS)

Thruster

Funaki (ISAS)

Bus

Takashima (ISAS)

Data

Kanda (Osaka

city)

Detector

Numata (Maryland)

Ando (Tokyo)

Mission phase

Design phase

Collaborations LISA

1st LISA-DECIGO workshop held in JAXA/ISAS (Nov. 2008) Stanford Univ.

Charge control using UV LED, etc. ⇒　MOU NASA Goddard

Fiber laser　⇒　 started discussion JAXA formation flight group

Formation flight Big bang center of the Univ. of Tokyo

DECIGO adopted as one of the main themes Advanced technology center of NAOJ

Will make it a main nucleus of DPF UNISEC (University Space Engineering Consortium)

Started discussion

Funding Status Proceeded to the final hearing as one of the

two candidates for the 2nd small science satellite run by JAXA/ISAS (launching three missions between 2012 and 2016), but not selected.

We will apply for the 3rd mission. (The selection will take place in 2010.)

Conclusions We need LCGT and DPF funded as

soon as possible to establish the GW astronomy in the future!