The Imaging X-ray Polarimetry Explorer (IXPE)
mission launched on December 9, 2021 on a SpaceX Falcon 9 rocket from NASA’s Kennedy Space Center
in Florida into an equatorial orbit at 540 km altitude. The payload
consists of three grazing incidence telescopes developed at NASA/MSFC each focusing on
X-ray polarization detectors provided by the Italian Space Agency (Agenzia Spaziale Italiana; ASI)
The spacecraft bus is from Ball Aerospace.
The observatory operates in pointing mode observing known targets for
multiple (but not necessarily consecutive) orbits, requiring precise and
stable pointing. The IXPE mission improves polarization sensitivity by two orders of magnitude
over the X-ray polarimeter experiment on the OSO-8
satellite. Recent polarimetry with
Polar focused only on gamma-ray
bursts while PolarLight, with an IXPE type of detector
had a limited area.
Lifetime : 9 Dec 2021– (operating)
Energy Range : 2–8 keV
Special Features : Provide simultaneous spectral, spatial and timing polarimetry measuraments
Consists in three identical telescopes each coupled with a Gas Pixel Detector.
- The Mirror Module Assemblies (MMA) consist of three grazing incidence
mirrors of Wolter-I type with 24 shells of nested parabolic and hyperbolic
sections, with diameter ranging from 165 to 277 mm. The MMA is mounted on an extendable boom,
deplay in orbit to reach 4m focal lenght, and equipped with laser meteorology
tracking to correct for motion, tip, and tilt deflections of the MMA.
Field-of-View (FoV) of 12.9 arcmin2 square;
Angular resolution (HPD) ~ 28 arcsec;
Effective area per module at 166 cm2 at 2.3 keV and 175 cm2 at 4.5 keV.
- The Detector Units (DU) are three Gas Pixel Detector (GPD) arrays each located at the
focus of one mirror. Each GPD provides position, energy, timing and polarization information
for each event. The GPD images the photoelectron tracks produces by the x-rays absorbed in the special
fill gas and from its initial emission direction is determined the polarization of the source. The
initial interaction point and the total charge in the track provide the location and energy of the
absorbed x-ray, respectively.
Sensitive area 13 x 13 arcmin
Spatial resolution (FWHM)≤ 123 µm (6.4 arcsec) @ 2 keV
Energy resolution (FWHM) 0.57 keV @ 2 keV (∝ √E)
Useful energy range 2 - 8 keV
IXPE elements have heritage : the MMA is based directly on that ART-XC launched on SRG, the deployable boom is a shorter version of that used by
NuSTAR, and the GPD was flown
Archive: The HEASARC hosts the IXPE archive.
- Enhance our understanding of the physical processes that produce X-rays from and
near compact objects such as neutron stars and black holes.
- Explore the physics of gravity, energy, electric and magnetic fields at their
[IXPE at HEASARC]
[IXPE at MSFC]
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Last modified: Wednesday, 23-Feb-2022 18:12:32 EST