nasa logo, link to nasa home page Goddard Space Flight Center
NASA
> GSFC > Astrophysics Science Division > IXO
   + Search NASA
+ Google Search IXO
+ Intranet + Fast Facts + FAQs + Contact Us + Site Map
+ Home + Science + Technology + People + News + Resources

Related sites

+ NASA
+ NASA GSFC
+ ESA
+ JAXA

 


print Print this page

X-ray Polarimeter

XPOL schematic diagram

A possible configuration for XPOL. Click the image for larger view

The X-ray Polarimeter (XPOL) is an imaging polarimeter, with polarization sensitivity of 1 percent for a source with a 2–10 keV flux of 1mCrab in a 105 s exposure. XPOL utilizes a fine grid Gas Pixel Detector (GPD) to image the tracks of photoelectrons produced by incident X-rays and determine the direction of the primary photoelectron, which conveys information about the polarization of the incoming radiation. XPOL also has spectrographic capabilities with a resolution of E/ΔE of ~5 at 6 keV and timing information at few ms level. The XPOL´s FOV of 2.5 arcmin × 2.5 arcmin and its spatial resolution is a good match to the mirror point spread function (PSF). See IXO Science Performance Requirements.

Data collected by the XPOL will mainly contribute to high-energy astrophysics, such as the study of Matter under Extreme Condition,Structure and Physics of Jets, and also to test theories of Quantum Gravity.

top of page Top

Polarimeter Polarimeter

XPOL photograph. Click the image for a larger view

XPOL schematic. Click the image for a larger view

Gas proportional counters are a well-established space technology. Virtually every X-ray observatory from Uhuru (1970) through BeppoSAX (1996) utilized some form of gas counter. Gas Pixel Detectors have been under development for several years. A GPD variant— the Time Projection Chamber polarimeter—is the heart of the GEMS SMEX mission, recently selected by NASA for a 2014 launch.

top of page Top

Selected References

  • Bellazzini et al., "A polarimeter for IXO", Proceeding of Roma Conference "The Coming of age of X-ray polarimetry", INAF/IASF-Rome, Italy, 2010. Download PDF.
  • A.M.Bykov, Yu.A.Uvarov, J.B.G.M.Bloemen, J.W. den Herder, J.S.Kaastra, "A Model of Polarized X-ray Emission from Twinkling Synchrotron Supernova Shells", MNRAS (in press), 2009. Download PDF.
  • Enrico Costa et al., "XPOL: a photoelectric polarimeter onboard XEUS", Proceedings of SPIE Astronomical Instrumentation 2008 Conference, 23–28 June 2008 Marseille, France, Vol. 7011–15. Download PDF.
  • Muleri, F. et al., Nuclear Instruments and Methods in Physics Research, A 584, 149–159, 2008. Download PDF.


 
esa jaxa nasa logos esa home page jaxa home page nasa home page