Suzaku Mission Overview
- High X-ray spectral resolution throughout the 0.2-10 keV energy band where the bulk of K-shell lines of astrophysically abundant elements (O-Ni) exist.
- Imaging spectroscopy of extended sources using non-dispersive spectrometers.
- Large collecting area for high sensitivity.
- Very large simultaneous bandwidth to enable disentangling complex, multi-component spectra.
Thus Suzaku is complementary to Chandra and XMM-Newton observatories.
Suzaku has three major instruments. These are:
- The X-Ray Spectrometer
(XRS), which is the acknowledged "primary" instrument.
This is the same instrument that
was to have been part of AXAF. It is a non-dispersive (thus,
high-efficiency) imaging (30-element) spectrometer (about 6.5 eV FWHM).
It is cryogenically cooled by an adiabatic diamagnetic refrigerator
within a helium dewar, which, as well as the XRS sensor, is provided by
GSFC. The helium dewar is located within a Japanese-provided solid neon
dewar, which in turn is cooled by a mechanical cooler.
The current estimate of the cryo lifetime is about 2.5 years, but it is
hoped to get to three. The life time depends upon design requirements
associated with considerations such as launch loads.
The detector array sits behind a conical foil mirror (X-ray Telescope,
or XRT) assembly provided
by the GSFC, with spatial resolution of about 1.8' half power diameter
(HPD). The effective area of this system at 6 keV is about 150
cm2.
- There are 4 units of X-ray
Imaging Spectrometer (XIS). Each XIS, an X-ray CCD camera,
is at the focus of an XRT. All 4 XIS units are co-aligned, with the
XRS field-of-view at its center. The telescopes are provided by GSFC,
while the CCD chips are the responsibility of MIT, and the digital
electronics are supplied by a consortium of Japanese institutions.
- The Hard X-ray Detector (HXD) is a non-imaging instrument provided by a Japanese consortium led by the University of Tokyo and ISAS/JAXA. It is a hard X-ray (of order 10-600 keV) collimated system of "well" detectors. The HXD is characterized by the low background of ~10-5 cts/s/cm2/keV; its sensitivity is higher than any past missions in the energy range from a few tens keV to several hundreds keV. The anti-counters, whose main purpose is to reject particle background, are also expected to detect transient high energy phenomena such as the gamma-ray bursts.
Important mission and instrument parameters are summarized in the tables below. See also a brief summary of the Suzaku spacecraft.
Orbit | Circular |
|---|---|
Altitude | 550 km |
Inclination | 31 deg |
Pointing Constraint | Within 25 degrees of perpendicular to the Sun (all the instruments) |
All Sky Monitor? | HXD is sensitive to ~4 PI solid angle, and may be used as ASM and gamma-ray burst monitor |
| XRS | XIS | HXD | |
|---|---|---|---|
| Energy Range | 0.3-12 keV |
0.2-12 keV |
10 - 600 keV |
| Number of Sensors | 1 |
4 (one CCD chip/sensor) |
1 (16 identical units) |
| Number of Pixels | 30 pixels (6x6 geometry) |
1024 x 1024 for each CCD |
- |
| Pixel Size | 625 micron x 625 micron |
24 micron x 24 micron |
- |
| Effective area per sensor | 100 cm2 @1 keV 150 cm2 @6 keV |
400 cm2 @1.5 keV 250 cm2 @6 keV |
160 cm2 @15 keV 300 cm2 @120 keV |
| Energy Resolution (FWHM) | 6.5 eV |
120 eV @6keV 50 eV @1 keV |
3 keV (10-30 keV) 9% (at 662 keV) |
| Field of View | 2.9'x2.9' |
19'x19' |
0.56 deg x 0.56 deg (E<100 keV) 4.6 det x 4.6 deg (E>200 keV) |
| Imaging Capability | Limited by the pixel size |
Full |
None (collimated) |
| Spatial Resolution | ~1.8' (HPD of XRT PSF) |
- |
|
| Others | ~2.5 yr lifetime |
- |
also observe gamma-ray bursts |
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