The rocket experiment demonstration of a soft x-ray polarimeter (REDSoX Polarimeter)
Author(s)
Ramsey, Brian .
Guenther, Hans Moritz
Windt, David L.
Gullikson, Eric M.
Pareschi, Giovanni
Tagliaferri, Gianpiero
Jorstad, Svetlana
Marscher, Alan
Weisskopf, Martin
Marshall, Herman
Date Issued
August 2017
Journal
Proceedings Volume 10397, UV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XX
Publisher
SPIE
Citation
Marshall, Herman, et al. "The Rocket Experiment Demonstration of a Soft X-Ray Polarimeter (REDSoX Polarimeter)." 6-10 August, 2017, San Diego, California, edited by Oswald H. Siegmund, SPIE, 2017, p. 21. © COPYRIGHT SPIE
Version
Final published version
Abstract
The Rocket Experiment Demonstration of a Soft X-ray Polarimeter (REDSoX Polarimeter) is a sounding rocket instrument that can make the first measurement of the linear X-ray p olarization of an extragalactic source in the 0.2-0.8 keV band as low as 10%. We employ multilayer-coated mirrors as Bragg reflectors at the Brewster angle. By matching the dispersion of a spectrometer using replicated optics from MSFC and critical angle transmission gratings from MIT to three laterally graded multilayer mirrors (LGMLs), we achieve polarization modulation factors over 90%. We present a novel arrangement of gratings, designed optimally for the purpose of polarimetry with a converging beam. The entrance aperture is divided into six equal sectors; pairs of blazed gratings from opposite sectors are oriented to disperse to the same LGML. The LGML position angles are 120 degrees to each other. CCD detectors then measure the intensities of the dispersed spectra after reflection and polarizing by the LGMLs, giving the three Stokes parameters needed to determine a source's linear polarization fraction and orientation. A current grant is funding further development to improve the LGMLs. Sample gratings for the project have been fabricated at MIT and the development team continues to improve them under separate funding. Our technological approach is the basis for a possible orbital mission. Keywords: X-ray, polarimeter, astronomy, multilayer, mirror, grating
MIT Department
Massachusetts Institute of Technology. Department of Physics
MIT Kavli Institute for Astrophysics and Space Research
Terms of Use
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Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1117/12.2274107
