Japanese Gravitational Wave Antenna DECIGO/DPF

Transcription

1 Japanese Graitational Wae Antenna DECIGO/DPF Mitsuru Musha, DECIGO Collaborations Institute for Laser Science, Uni. of Electro-communications International Conference of Space Optics (ICSO) , Oct. Tenerife, Spain

2 Outline Graitational Wae (GW) GW detection Space GW detection DECIGO oeriew roadmap DECIGO pathfinder (DPF) oeriew mission status purpose Summary

3 Graitational Wae detection Graitational Wae (GW) predicted in General Theory of Relatiity Motion of Mass inspiral, merger of NS explosion of super noa Ripples in graitational field Propagate as waes Open a graitational wae astronomy (different information from EM wae) GW-detection TAMA300 (Japan:300m) tidal force long-baseline F.P.M.I. h=dl/l<10-22 [ /Hz 1/2 ] LIGO (US.4km) GEO500 (Germany, UK 500m) VIRGO (Italy, France 3km)

4 GW detector strain sensitiity Seismic noise Thermal noise longer baseline silent area low temperature TAMA300 Frequency noise & shot noise higher power higher freq. stability frequency [Hz] 10-24

5 Future plans upcoming plans terrestrial KAGRA (Japan:3km) elisa ad.virgo TAMA300 ad.ligo space DECIGO KAGRA DECIGO (Japan) DPF frequency [Hz] elisa (EU) LPF

6 Outline Graitational Wae (GW) GW detection Space GW detection DECIGO oeriew roadmap DECIGO pathfinder (DPF) oeriew mission status subsystem status Summary

7 DECIGO : pre-conceptual design DECIGO (DECi-hertz Interferometer Graitational-wae Obseratory ) Differential Fabry-Perot interferometer Drag-free spacecraft mirror 3 S/C formation flight 3 Fabry-Perot interferometer L=1000 km F=10 mirrors w=100kg. Φ=1m Drag-free control laser power 10W@0.5 mm Light source Photo detector Arm-caity 1000 km Strain sensitiity 2x10-24 / Hz@0.1Hz

8 DECIGO : pre-conceptual design Earth Record disk sun correlation angular resolution Orbit : record disk around the sun Constellation : 4 interferometer units 2 oerlap units : cross correlation for stochastic background 2 separated units : increase angular resolution

9 DECIGO : sensitiity configuration Arm length DECIGO Fabry-Perot 1000 km elisa Optical transponder km elisa DPF KAGRA (1 unit) DECIGO (correlated)

10 DECIGO : sensitiity configuration Arm length DECIGO Fabry-Perot 1000 km elisa Optical transponder km DPF Radiation pressure noise (1 unit) DECIGO (correlated) Shot noise

11 DECIGO : target IMBH binary inspiral NS binary inspiral Stochastic background Galaxy formation Very early unierse Cosmology (inflation, dark energy) elisa DPF KAGRA (1 unit) DECIGO (correlated)

12 DECIGO -roadmap roadmap to DECIGO Mission objectie scope R&D Fabrication Space test of key tech. GW detection DPF Earth graity obseration Single small satellite Short FP interferometer R&D Fabrication Pre-DECIGO GW detection with minimum spec FP caities between S/Cs 3 space crafts I interferometer unit R&D Fabrication DECIGO GW astronomy 3 space crafts 3-4 units

13 Outline Graitational Wae (GW) GW detection Space GW detection DECIGO oeriew roadmap DECIGO pathfinder (DPF) oeriew mission status subsystem status Summary

14 DPF : oeriew DECIGO pathfinder (DPF) First milestone mission for DECIGO Purpose feasibility tests of key technologies scientific obserations Single small satellite mission weight : 200 kg size : 950x950x1000 mm orbit : low earth orbit altitude : 500 km power : sap-940w, battery: 50 Ah mission thruster stabilized laser interferometer modul Epsilon rocket 2019 bus thruster solar paddle Small Science Satellite Series (JAXA)

15 DPF : configuration Single Fabry-Perot interferometer Drag-free control Local sensor signal is fedback to thruster Frequency-stabilized laser l : 1030 nm p : 20 mw df : 0.5 Hz/ Fabry-perot caity length : 30 cm Finesse : 100 test mass : 50x50x50 mm 2 kg mission fig Strain sensitiity dl/l < 2x10-15 / 1Hz Current status : Deeloping BBMs for each elements

16 Subsystem: light source Light source for GW-detector single-frequency, single transerse mode, CW, linear polarized -- Requirements - Waelength [mm] output power [W] frequency noise [Hz/Hz 1/2 intensity noise [1/Hz 1/2 ] DPF Df = 1Hz 10-8 DECIGO Iodine-stabilized fiber DFB 1030nm P=200 mw A.Suemasa et.al 9,Oct. 12:20- (high.stab.ref)

17 Subsystem: TM & input opt. Test mass Caging frame Electro-static sensor/actuator Test mass lock mechanism Charge management system Al-Cu Low magnetic susceptibility 50x50x50 mm Input optics Monolithic optical bench Silicate bonded on ULE plate F = 120 mm

18 Subsystem: IF module Interference module (preliminary) test-mass module input-output optical system drag-free control

19 Subsystem: Drag-free control Disturbance LEO 500km solar radiation pressure 20mN@DC air drag typ 100mN annual/season dependent No momentum wheel is loaded Micro thruster 10mN x 8 : drag free control 100mNx2 : DC drag cancellation Feep (field-emission electric propulsion) Attitude control should work w/o thrusters passie owing to S/C shape actie MTQ control

20 DPF : purpose Feasibility tests space-borne frequency-stabilized laser drag-free control of test masses precision interferometric measurement Graitational wae detection dl/l < 2x10-15 / Hz inspiral & merger of IMBH h f=4 Hz, d=10kpc Galaxy formation GW eents in our Galaxy Global graity field from satellite orbit & graity gradiometer Shape of the earth density distribution ground water motion comparable sensitiity with other missions (CHAMP, GRACE, GOCE)

21 Summary DECIGO Space graitational wae detector Hz fruitful science ery beginning of the unierse dark energy, dark matter galaxy formation plan to be launched 2030 DECIGO pathfinder (DPF) milestone mission for DECIGO scientific obserations graitational wae graity field current phase: deeloping a breadboard model mission proposal to JAXA Launched 2019

22 Acknowledgements Acknowledgement This research is supported by the Japan Aerospace Exploration Agency (JAXA) the Japan Society for the Promotion of Science (JSPS) Grand-in-Aid for Scientific Research

23 Collaborations & Supports Supports from LISA Technical adices from LISA/LPF experiences Support Letter for DECIGO/DPF, Joint workshop ( ) Collab. with Stanford uni. group Drag-free control of DECIGO/DPF UV LED Charge Management System for DPF Collab. with NASA/GSFC Fiber Laser, Earth s graity obseration Collab. with JAXA naigation-control section Formation flight of DECIGO, DPF drag-free control Geophysics group (Kyoto, ERI, UEC, NAOJ) Adanced technology center ( ATC) of NAOJ JAXA s fund for small satellite deelopment Research Center for the Early Unierse (RESCEU), Uni. of

24 Mission status of DECIGO pathfinder Proposal to JAXA DPF is one of the candidate of JAXA s small satellite series (SPRINT series). using epsilon rocket program 1 st mission (2013): SPRINT-A /EXCEED 2 nd mission (~2014/15) : SPRINT-B /ERG The program framework was changed: ~10 M$ payload mission to ~150 M$ full mission AO from JAXA : December 2013 Deadline : End of February. - 7 mission proposals including DPF DPF was dropped in the first down-selection (May) Started discussions on the next strategy Next-generation Solid rocket booster (M-V FO) Fig. by JAXA 85M$

25 DECIGO : requirement Requirements for DECIGO Sensor noise shot noise limited 3x10-8 m/ Hz Other noise should be well below the shot noise laser frequency noise 1 Hz/ Hz (CMRR 10 5 ) radiation pressure noise Acceleration noise 4x10-17 N/ Hz (1/50 of LISA) External force sources fluctuations of magnetic field electric field graitational field temperature, pressure etc.

26 Strain [1/Hz 1/2 ] Sensitiity & target Terrestrial detector : 10Hz - 1kHz neutron star binaries DECIGO : 0.1-1Hz GW from early unierse IMBH LISA : 1mHz 10mHz SMBH LISA Foreground GW From WD binaries Merger of SMBH binary Binaries in the galaxy DECIGO Background GW From early unierse (Wgw=10-14 ) DPF limit Merger of NS binary pilserー (1yr) Graity-gradient noise (Terrestrial detectors) Explosion of super noae ScoX-1 (1yr) KAGRA Frequency [Hz]

27 Science by DPF Slide by Ando Astronomical obseration GW from merger of IMBHs formation mechanism of supermassie BHs 30 GCs within DPF range Obseration of earth Graitational potential shape of the earth Enironment monitor Comparable sensitiity with other missions

28 Test-mass Test mass Low susceptibility (10-6 [SI]) High density material Mass ~1kg Exploring material Alloy of paramagnet / diamagnet Reasonable combination of elements Hopefully not precious metals Al-Cu case Al-Sn case

29 GOCE & DPF Global graity field is measured by graity gradiometer on S/C (Satellite GG) GOCE DPF (ESA, 2009-) (JAXA, 2019-) Drag-free controlled graity gradiometer 3-axes altitude 295 km Sensitiity 5x10-12 m/s 2 /Hz 1/2 Baseline 0.5 m Weight 1,200 kg 1-axis 500 km, 9x10-15 m/s 2 /Hz 1/2 0.3 m 400 kg

30 Noise leel [1/Hz 1/2 ] Sensitiity of DPF Displacement Noise [m/hz 1/2 ] Laser source : 1030nm, 25mW IFO length : 30cm Finesse : 100, Mirror mass : 1kg Q-factor : 10 5, Substrate: TBD Temperature : 293K Satellite mass : 450kg Altitude: 500km Thruster noise: 0.1µN/Hz 1/2 (Preliminary parameters) Fig. by Ando Geograity PM acceleration Noise Laser Radiation pressure noise Thruster noise Frequency [Hz] Caity length: 30cm Laser: 1030nm, 25mW Finesse: 100 Mirror mass: 1kg Q alue of a mirror: 10 6 Laser Frequency noise Shot noise Mirror thermal

31 Charge management system Charge management system UV-LED based system Collaboration with Stanford SSGD I/F design for DPF BBM Functional test Simulation of charge-up in DPF orbit Experiment setup ongoing

32 Test-mass module test Ground-based test setup Double torsion pendulum 2DoFs micrograity enironment 阿 久 津 氏 講 演

33 Laser sensor Precision displacement sensor for earth graity measurement Michelson laser interferometry Light source : fiber-coupled DFB laser Offset layout using corner cube reflector 6 modules on 3 faces:for 6 d.o.f. sensing BBM: 30x30x130mm module Initial functionality test Control demonstration /characterization Optical Fibers Laser diode Accelerometer To IFOs Control sig. Actuator drier Sero unit Dif. Amp. Referenc e mass IFO out Laser & controller Mirror Detectors IFO Actuators Self Calib. Ref. Mirror Calib. signal Acceleration output

34 Attitude/drag-free control syst Micro thruster Actuators for satellite control Wide-range throttling capability: 0-100µN Low thrust noise: 0.1µN/ Hz Fast control: >10Hz Long life: >0.5year Candidates: Electrostatic microthrusters FEEP(field-emission electric propulsion) Colloid thruster Ion thruster BBM test and characterization ongoing ION 5-100μN U-Tokyo, JAXA FEEP 0.1-1μN : Flight proen

35 GW energy density ratio GW from early unierse Earlier unierse Smaller horizon scale High GW freq. Original Figure by S. Kuroyanagi (2011) KAGRA DECIGO GW from Inflation Frequency [Hz]

36 Global graity field Measure graity field of the Earth from satellite orbit and graity gradiometer Determine global graity field GPS satellites density distributions Temporal ariation ground water motion strain in crusts by earthquakes and olcanoes On going GRACE: F.F of 2 S/C GOCE: 1 S/C gradiometer Araya (UT), Fukuda (KU) Next generation: GRACE FO same config. & sensitiity as GRACE