Space Gravitational Wave Detection in China

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Space Gravitational Wave Detection in China

• Yue-Liang Wu
• University of Chinese Academy of Sciences (UCAS)
• Kavli Institute for Theoretical Physics China
  (KITPC/ITP-CAS)
• On behalf of Working Group on Space GWD/CAS
• First eLISA Consortium
  Meeting
• APC-Paris, France, Oct.
  22-23, 2012

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Strategic Goal of Space Science in China A
Roadmap to 2050

• --------------------------------------------------
  ---------
• Original breakthroughs should be made in
  directly detecting black hole, dark matter, dark
  energy, gravitational waves, .
• -- Space Sciences
  Technology
• in China A
  Roadmap to 2050,
• (Edt H.D. Guo, J.
  Wu
• Science Press
  Springer, Beijing, 2010)

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Space Science Strategy Pioneer Program,
(SSSPP/CAS)

• Leading Group
• Director H.J. Yin (Vice-President of CAS)
• National Scientific Committee of Space Science
• Chairman H.J. Yin
• Office of SSSPP
• Director Y.J. Yu (HQ CAS)
• National Space Science Center
• Chairman J. Wu (Director of Space Science
• Application Center)

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Studies on GW Detection in China

• Many workshops and meetings have been held in
  China
• Ground GW detection
• Australia-China collaboration
• ASTROD suggested by Prof. W.D. Ni
• Space GW Detection of China (2008-2011)
• Feasibility study on Space G-W Detection.
• A suggestion on SGD program similar to LISA in
• frequency range f 1.0-10-2 Hz
• Working group on SGD mission for joining the NGO
  Program (2012 - )

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World-wide Future GW detection projects
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Suggestion of Space GWD in China

• Feasibility study based on ALIA Mission concept
  (2008-2010).
• Preliminary studies phase of CAS project for
  began and a mission design (2010-2012).
• Ground based experiments in key technologies and
  theoretical studies. Accepted as a part of
  national program in 2011 and will be started in
  the near future after a starting review
  (2011-2015) .

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Chinese Mission Options (Inst. Appl. Math./CAS)
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Mission Design

• Assumptions
• Sensitivity of inertial sensor one order better
  than that of LISA
• (at higher frequency window)
• Suppress shot noise by increasing laser power and
  diameter of telescope

1.5 order more sensitivity than LISA.
Sensitivity floor shifts to the right.
Baseline Design Parameters (Peter Bender , CQG,
21, S1203 (2004))


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Options ( Inst. Appl. Math., CAS)
3L and 3H are currently preferred as far as
technology development is concerned
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Main Scientific Purpose

• Overlapped with LISA
• Sensitivity floor shifts to the right.
• Enhanced Intermediate mass black holes (IMBH)
  detection
• Light seed Population III remnants
• Almost equal mass coalescence (High
  redshift)
• Intermediate mass ratio spiral (Low redshift)

• Overlapped with BBO/DECIGO
• The major purpose of space gravitational wave
  detection in bandwidth between 0.1 and 1.0 Hz is
  to search for the stochastic back ground of
  gravitational waves coming from the early
  university
• Primordial Gravitational Wave Background
  (inflation, electroweak transition, Population
  III stars core collapse)
• Bursts from hypothetical cosmological structures
  like cosmic string and other topological defects
  in the early Universe

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Better IMBH Detection Extra Sciences on offer

• Main difference from LISA
• Sensitivity floor shifts to the right.
• Enhanced Intermediate mass black
• holes (IMBH) detection

• Light seed Population III remnants
• Almost equal mass coalescence (High redshift)
• Intermediate mass ratio spiral (Low redshift)

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Working Group on SGWD/CAS (2012)

• Heads
• W.R. Hu (Institute of Mechanics),
• Y.L. Wu (Univ. of Chinese Academy of Sciences,
  UCAS).
• Members
• L.Q. Peng (Bureau of Basic Research Sciences),
• C.F. Qiao and Y.S. Pu (Univ. of Chinese
  Acad. of Sci.),
• R.Q. Lau (Institute of Applied Math.) ,
• G. Jin and Q. Kang (Institute of Mechanics),
• Y.X. Nie and Z.Y. Wei (Institute of Physics),
• M. Li and Y.Z. Zhang (Institute of Theoretical
  Physics),
• S.N, Zhang (Institute of High Energy Physics)
  
• Z.L. Zhou and Y.T. Zhu(National Astronomy
  Observatory),
• M.S. Zhan and L.S. Chen (Wuhan Institute of
  Phys. Math.).

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Possibility on Joining NGO Program

• Telescope of NGO (Nanjing Institute of
• Astronomy and Optics Technology, CAS)
• Collaboration with MP Institute for
  Gravitational Physics on Laser Interferometer
  (Institute of Mechanics, CAS)
• Collaboration with Trento University for
  inertial sensors (Huazhong University of Sci.
  Tech.)
• Others

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Nanjing Institute of Astronomical Optics
Technology Space Telescope
LAMOST
Antarctic telescope
Zerodur mirror
SiC Mirror
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Critical Requirements for the Telescope Subsystem
Parameter Derived From NGO
1 Wavelength 1064 nm
2 Net Wave front quality of as built telescope subs system over science field of view Pointing l/20??RMS
3 Telescope subsystem optical path length stability under specified environment Path length Noise/ Pointing where 0.0001 lt f lt 1 Hz 1 pm 10-12 m
4 Field-of-View (Acquisition) Acquisition /- 200 mrad
5 Field-of-View (Science) Orbits /- 7 mrad out-of-plane2 /- 4.2 mrad in-plane
6 Transmitted beam diameter on primary mirror Shot noise/ Pointing 0.92D
7 Entrance Mirror Diameter Noise/ pointing 200 mm
8 Entrance Pupil Pointing Entrance of beam or primary
11 Location of image of primary mirror (exit pupil) Pointing 10 cm (on axis) behind primary mirror
12 Pupil distortion SNR 10
13 Beam size on bench short arm interferometer 5 mm
14 Mechanical length 350 mm
15 Optical efficiency Shot noise gt0.85
16 Scattered Light Displacement noise lt 10-10 of transmitted power
17 Telescope spacer variation 2.5 microns
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Space Telescopes Utilize the Goddard Space
Flight Center design
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Material and Fabrication

• Mirrors--- Zerodur
• Telescope spacer SiC , Asymmetric
• Quad-Pod design
• Wavefront quality realized in mirror lab.

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Stability Test and Measurements
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Cooperation Between AEI and IM/CAS

• Jointly develop the space laser interferometer
  for NGO
• Share the future space laser interferometer duty
  in NGO mission.

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Space Interferometer on the earth
base Institute of Mechanics/CAS Institute of
Physics/CAS Wuhan Institute of Phys.
Math./CAS HUST
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Further Ground Based Experiments

• 1?Measurement of distance variation
• 2?Noise evaluation
• 3?Pointing control
• 4?Phase lock
• 5?Ranging tone system demo
• 6?Sideband-sideband scheme demo
• 7?TDI demo

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Laser metrology Demonstration System _at_ IMECH CAS
Two M-Z interferometers (equal arm)
Heterodyne detection
Offset frequency from 10kHz to 500kHz
Laser wave length 633nm
Isolated base
Clean room class 1000
Thermal stabilized by air-condition
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Laser metrology Demonstration System _at_ IMECH CAS
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HUST
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HUST
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Cooperation Agreement between HUST and Univ.
Trento

• Goal of cooperative research
• Modeling and evaluation of the performances of
  inertial sensors for GW missions
• Development of ground-based testing facilities,
  and research on inertial sensors
• Design of some engineering components and their
  performance verification
• Training of research groups
• Contents of cooperative research
• Modeling and the analysis of spurious forces
• Developing torsion pendulum for ground-based
  tests
• Experimental verification of the noise model and
  sensor performance
• Coupling between interferometer and inertial
  sensor
• Coupling between inertial sensor and drag-free
  control

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Cooperation Agreement between HUST and Univ.
Trento
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Progress of Inertial sensor of LISA Pathfinder

• Performance research of inertial sensor using
  torsion pendulums
• Push to develop the inertial sensor engineering
  model

10-14 Nm/Hz1/2 Univ. Trento, Italy PRL 91
(2003) 151101 PRL 103 (2009) 140601 PRL 108
(2012) 181101
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Progress of HUST

• To develop a two-stage pendulum to test
  performances of inertial sensor
• The facility can be used to simulate 2D motions
  of the proof mass, which is important to
  investigate cross-coupling of PM

910-14Nm/Hz1/2 Tu et al., CQG 27 (2010)
205016 Zhou et al., CQG 27 (2010) 175012
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Inertial Sensor Development in HUST
Two space experiments have been scheduled
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Inertial SensorHuazhong University of Sci.
Tech. (HUST)
Progress Two-stage torsion pendulum, (Liu et
al., CQG 2010) 10-10m/s2/vHz for small gap 0.1mm
(Tu et al., CQG 2010)
Next-step Fused-fiber suspension, thermal limit
1fNm / vHz at 2mHz To determine differential
shape and material proof mass (PM) To measure the
effects of PM with temperature, electric,
magnetic To investigate the cross-coupling
between the DoF of PM
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Others

• To be considered and discussed

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Prospect

• Step I (20112015)
• Ground studies on theoretical analyses and key
  technology
• Step II (20162020)
• Space technology for a satellite of key
  technology experiment
• Step III (2020 2030)
• Satellite of GWD/CN or joining NGO

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Thank You!