Transcript Development of a very small satellite “Tsubame” for Hard X-ray polarimetry of GRBs ○T.

Development of a very small satellite
“Tsubame”
for Hard X-ray polarimetry of GRBs
○T. Toizumi, T. Enomoto, Y. Yatsu, N. Kawai,
S. Matsunaga (Tokyo Tech),
T. Nakamori, J. Kataoka (Waseda Univ.),
& S. Kubo (Clear Pulse .co)
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Contents
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The “Tsubame” Project
Description of Hard X-ray Polarimeter (HXCP)
Results of X-ray Beam Test
Summary
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Cube-Sat Project in Tokyo Tech
We have been working on cube sat projects since 2001~
In Operation
CUTE I(2003)
In Operation
Cute1.7+APD(2006)
Cute1.7+APD II (2008)
Now Developing
Tsubame
Tsubame is the 4th very small satellite in Tokyo Tech.
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Dimension: 50 x 50 x 50 cm3
Total Mass: 50 kg
Attitude Control: 4 CMGs (6 degrees/s)
Launch: Early 2013~
Science Instruments of the Tsubame
For “Real time” and “Automatic” polarimetry,
Two detector systems are onboard.
Wide-field Burst Monitor (FoV: 2π str)
→ Detection and Localization
Hard X-ray Compton Polarimeter
→ Polarimetry at 30-200 keV energy band
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Wide-field Burst Monitor
Hard X-ray Compton
Polarimeter
Observation Sequence
1. Trigger and
Localization
2. High Speed
Pointing
3. Observation
(<15 s after the trigger)
Hard X-ray Compton Polarimeter
APD
η
MAPMT
Polarized direction
MAPMT
CsI(Tl) scintillator
APD
Plastic scintillator
・Detection principle : anisotropy of the Compton scattering
・Performance
Effective area： 7 cm2 @ 100 keV（Physical area: 36cm2）
Modulation Factor: 47.8 ±0.9 %
Minimum Detectable Pol.(3σ): 6.2 % (3.2x10-5 erg/cm2/s @25-100keV)
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Development of prototype polarimeter
ASIC
for APD
ASIC
for APD
ASIC for PMT
IFC
Prototype polarimeter for beam test
・ Plastic 16 units, CsI 16 units
(Partial model of 1 PMT + 16 APDs)
ASIC for
APD
ADC
trigger
APD
ASIC for
PMT
hold
MAPMT
APD
data
APD
CsI
array
MAPMT
trigger
~20 cm
CsI
array
plastic
Geometry of
the Detector
hold
Plastic
array
CsI
array
data
CsI
Plastic
array
ADC
Interface Card(IFC)
Data bus (outside)
・Two types of ASIC
・ADCs triggered by coincidence
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Polarized Beam Test @KEK-PF
・2009/Dec/20th ～ Dec/24th
・(KEK @ Tsukuba, Japan)
Photon Factory (PF) BL 14A
Polarized direction
Polarized
X-ray beam
Rotated
per 45 degree
Polarized direction
90 % polarized
82.5 keV X-ray
beam
Equatorial
mount
Attenuator
(Tungsten-foil)
Polarimeter
Setup Image
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Spectrum of the recoil electrons
detected by Plastic (PMT)
Spectrum of Scattered photons
detected by CsI(Tl) (APD)
Coutns
Coutns
Obtained Spectra
Compton
Photoelectric abs.
noise
Deposit Energy [keV]
Photon Energy [keV]
Total energy (keV)
Total energy (keV)
Deposit Energy [keV]
Extracting
Compton events
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Compton event
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Deposit Energy (keV)
Making the modulation curve of polarization
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All data are
combined
0°
Polarized direction
Simulation
MF = 68.7 ± 1.2 %
Azimuth Angle [deg]
Counts
Counts
Reducing
systematic error
Beam test
MF = 72.3 ± 5.4 %
Azimuth Angle [deg]
The beam test result seems consistent with the simulation
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We are now developing Engineering Model
Passive Shield
CsI
APD
Plastic
Data processing
boards
PMT
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HV module
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HV module
Data processing boards
Lighter (～4 kg/unit)
ASIC for APDs
Passive Shield （W, Sn, Pb）
Summary
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We are now developing the small satellite Tsubame to
be launched after 2013
 To measure the polarization of GRBs
 Expecting significant detection of X-ray polarization
for 6 GRBs/yr.
Evaluation of the performance of the polarimeter by
irradiating polarized X-ray beam @KEK-PF
The results are consistent with the simulation
Manufacturing the EM of polarimeter based on prototype
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