Post on 20-Jan-2016
transcript
LU Fangjun(on behalf of the HXMT team)
Institute of High Energy Physics, Chinese Academy of Science
Current Status of
the Hard X-ray Modulation Telescope Project
Scienctific objectives
Introduction to the Payloads
Project status and schedule
Summary
Outline
The Hard X-ray Modulation Telescope project was proposed in 1993.
In the first proposal, HXMT contains 18 NaI/CsI phoswich scintillators with a total detection area of 5000cm2, aiming for a hard X-ray (20-250 keV) all-sky survey and pointed observations.
The mission was officially approved in March 2011.
1. Scientific objectives
Low energy X-ray telescope added
High energy X-ray telescopes only
< 2005 2005 2006 2010
Medium Energy X-ray Telescope added
Optimised for the working temperatures of the detectors
1. Scientific objectives
Evolution of the payloads onboard HXMT
Satellite Facts:Weight: ~2800 kgOrbit: 550 km, 43°Attitude: 3-Axis Stabilized precision 0.1 °Lifetime: 4 yearsObservation modes: Scan and pointing
1. Scientific objectives
HXMT collaborationInstitute of High Energy Physics (PI institute, payloads, scientific operation)Chinese Academy of Space Technology (satellite platform)National Space Science Center, CAS (space environment monitor, mission operation)Tsinghua University (participation in payloads and scientific operation)
Large sky-area scanDiffuse X-ray emission: cosmic X-ray background; X-ray
emission from the Galactic ridge and the Galactic center
regionDetection of new (transient) sources and constrain their
broad band (1-250 keV) propertiesFollow up observation of gravitational wave burstsPointed observationsX-ray binaries: multiwavelength temporal behaviors,
broad band spectra and Fe emission line
Equation of state in strong magnetic field: AXP, X-ray
Bursts
Monitoring of Blazars and bright AGNs
Sciences with HXMT
1. Scientific objectives
With the blocked, narrow, and broad FOVs, HXMT can subtract
the charged particle induced background and can estimate the
relative contributions of point source and diffuse background,
and can thus measure the diffuse X-ray emission in 1-250 keV.
The quality of the measurement is highly related to the in-orbit
particle background determination.
Diffuse X-ray background
(Türler et al. 2010, A&A 512, 49)
Blocked: only sensitive to local particle induced bkg
Broad: source + diffuse X-ray bkg+ local bkg
Narrow: source + diffuse X-ray bkg+ local bkg
Advantages of HXMT’s FOV
1. Scientific objectives
Detection of transient sources
Transient source
1. Scientific objectives
HXMT will do time resolved broadband spectroscopy for the brightest X-ray binaires.
Illustration of a black hole X-ray binaryBroad Fe-Kα line of XTE J165-500 byXMM-Newton pn (Credit: ESA/XMM-Newton)
Mission Spectral resolution (eV, @ 6keV)
Timing resolution(ms)
Energy coverage(keV)
Detection Area (cm2, @6keV)
Strongest sources without pileup(Crab)
HXMT 150 1 0.7-250 240 No limit
XMM-Newton (pn, timing mode)
150 0.03 0.5-10 800 0.085
Chandra (ACIS, cc mode) 150 2.7 0.5-8 300 0.02
RXTE 1200 0.006 2-250 6000 No limit
1. Scientific objectives
HE: NaI/CsI, 20-250 keV, 5000 cm2
Size : 1900×1650×1000 mm
ME:Si-PIN
,5-30 keV, 952 cm2
LE:SCD,1-15 keV, 384 cm
2
Star tracker
2. Introduction to the payloads
HXMT/HE Components assembly• 18 main collimated phoswich detectors• 18 calibration detectors (automatic gain control)• 18 charged-particle anticoincidence plates (6 top +12 lateral side)• 3 particle monitors
The High Energy X-ray Telescope (HE)
2. Introduction to the payloads
The Medium Energy X-ray Telescope (ME)
ME uses 1728 Si-PIN detectors read out by 54 ASIC (application specified integrated circuit). The energy coverage of ME is 5-30 keV, and the total detection area is 952 cm2. The in-orbit working temperature of ME is -40 to -20 ℃
2. Introduction to the payloads
2×2CCD236
16 cm2
The low Energy X-ray Telescope (LE)
2. Introduction to the payloads
LE consists of 3 detector boxes, and each boxes contains 32 CCD 236 chips, which have a time resolution of 1ms and energy resolution of <140 eV (@6 keV) . The total detection area is 384 cm2. The in-orbit working temperature is between -80 to -40 .℃
The sensitivities of the three telescopes of HXMT. The sensitivities of NuSTAR, INTEGRAL/IBIS and RXTE/HEXTE were reprinted from Koglin et al. (2005)3.
2. Introduction to the payloads
HXMT/LE
HXMT/ME
HXMT/HENuSTAR
INTEGRAL/IBIS
RXTE/HEXTE
15
2. Introduction to the payloads
HXMT RXTE INTEGRAL/IBIS SWIFT NuSTAR
Energy Band (keV)
LE: 0.8-15ME: 5-30HE: 15-250
PCA: 2-60HEXTE: 15-250
15-10000 XRT: 0.5-10BAT: 10-150
3-79
Detection Area (cm2)
LE: 384ME: 950HE: 5000
PCA: 6000 HEXTE: 1600
2600 XRT: 110BAT: 5200
847 @ 9 keV60 @ 78 keV
Energy Resolution (eV)
150@ 6 keV2500@ 20 keV10000@60 keV
1200@6keV10000@60 keV
8000@ 100 keV
150 @ 6 keV3300 @ 60 keV
900 @ 60 keV
Time Resolution (ms)
LE: 1ME: 0.18HE: 0.012
PCA: 0.001HEXTE: 0.006
0.06 XRT: 0.14, 2.2,2500 BAT: 0.1
0.1
Sensitivity (@100keV, 3σ ,105s, mCrab)
0.5 1.5 3.8 9 0.03 @ 20 keV
Comparison between HXMT and other major hard X-ray telescopes
The Mechanical Model of the satellite was finished in 2012. The payloads and platform both passed the dynamical environment tests.The mechanical model of the satellite in
dynamical environment tests (2012.11)
Measureing the weight center and rotation inertia of the telescope
(2012.11)
3. Project status and schedule
The tests of the electric performance of the payloads were finished in Dec. 2012, and those of the whole satellite were finished in early March of 2013.
3. Project status and schedule
The electric model of HXMT’s payloads in assembling and testing (2012.12).
Vacuum thermal balance tests of the satellite were carried out in Dec, 2012. The quasi-qualification models of all the detectors joined the tests. Those of HE and LE worked well during the tests, but that of ME had some problems with the FPGA, which were fixed and tested early this year.
The payloads after thermal control coating
Some of the components jointed the vacuum tests
3. Project Status and schedule
October 22 , 2013 19
3. Project status and schedule
All the space qualification models and the environmental tests were finished in 2013 and 2014.
• The electric fitting of the flight models of the payloads is almost finished.
• Environment tests started.• Calibration procedures fully tested for HE and LE,
and partly for ME.• The payloads will be delivered before the end of
November, and the expected launch date will be around September next year.
October 22 , 2013 20
3. Project status and schedule
The ground calibration facilities
Finished in May 2014. The energy coverage of the monochromatic beam is 15~150 keV
HE calibration facility
Finished in the end of 2014. The energy coverage of the monochromatic beam is 0.8-30 keV.
ME 、 LE calibration facility
Comparison of the different sampling methods for calibration
The calibration results are consistent with each other. The 27 points sampling mode will be used.
27 points
192 points
22 annuli
The energy linearity and resolution of the HE main detector
How to deal with the “deviations” at the energy of the Iodide absorption line?
The detection efficiency of the HE main detector
The measured data and the simulation are not consistent especially in the low energy band. More factors such as the air absorption, moving of the beam position with energy need to be considered.
Preliminary calibration of LE
LE 正样探测器 C 机箱能量分辨率随温度变化的初步标定结果
Signal amplitude as a function of temperature for LE flight model
The calibration procedure of ME has also been tested.
• The electric fitting of the flight models of the payloads is almost finished.
• Environment tests started.• Calibration procedures fully tested for HE and LE,
and partly for ME.• The payloads will be delivered before the end of
November, and the expected launch date will be around September next year.
October 22 , 2013 29
4. Summary
Thank you for your attention!
Backup materials
Detectors LE: SCD, 384 cm2;ME : Si-PIN, 952 cm2
HE : NaI/CsI, 5000 cm2
Energy Range LE: 1-15 keV;ME: 5-30 keV;HE: 20-250 keV
Time Resolution HE: 25μs; ME: 180μs;LE: 1ms
Working Temperature
HE: 18±1 ; ME: -50~-20 ; LE: -80-45℃ ℃ ℃
Energy Resolution LE: 2.5% @ 6 keV ME: 14% @ 17.8 keV HE: ≤16% @ 60 keV
Field of View of one module
LE: 6°×1.6°; 6°×4°; 60°×3°; blind;ME: 4°×1°; 4°×4°; blind;HE: 5.7°×1.1°; 5.7°×5.7° ; blind
Source Location <1' (20σ source)
Characteristics of the HXMT Mission
Orbit Altitude: ~550 km ; Inclination: ~43°
Attitude Three-axis stabilizedControl precision: ±0.1°Measurement accuracy: ±0.01°
Data Rate LE: 3 Mbps; ME: 3 Mbps; HE: 300 kbps
Payload Mass ~1000 kg
Nominal Lifetime 4 years
Working Mode Scan survey, small region scan, pointed observation
Total background of HE varying with time
Different background components of HE
Background components of ME Background components of LE
Simulation of the in-orbit background of HXMT
Short timescale varibility of black hole X-ray binaries up to 250 keV.
The hard X-ray detectors
RXTE/HEXTE 、 Suzaku/HXD and BeppoSAX/PDS
are too small (<1000 cm2) , and INTEGRAL/ibis and
SWIFT/BAT are of too high background to study the
short timescale hard X-ray varibilities of black hole
X-ray binaries. HXMT, with the large detecting area
(5000 cm2, 20-250 keV) and the relatively small field
of view (low background) , will provide unique
opportunity for studies in this field.
Variability amplitude as a function of energy for several black hole binaries. (Kaaret 2004)
Test the performance of the automatic gain control by changing the angle between the main detector and the geomagnetic field.
With out the gain control , the amplitude variation of the same energy incident photons can reach 10.6% , and it decreased to 0.243% using the AGC, the effect on the energy resolution is as small as 1.31% 。
Automatic Gain Control