Abstract

The Spectrometer/Telescope for Imaging X-rays (STIX) is a hard X-ray imaging spectroscopy device to be mounted in the Solar Orbiter cluster with the aim of providing images and spectra of solar flaring regions at different photon energies in the range from a few keV to around 150 keV. The imaging modality of this telescope is based on the Moiré pattern concept and utilizes 30 subcollimators, each one containing a pair of co-axial grids. This paper applies Fourier analysis to provide the first rigorous description of the data formation process in STIX. Specifically, we show that, under the fundamental frequency approximation, the integrated counts measured by STIX subcollimators can be interpreted as specific spatial Fourier components of the incoming photon flux, named visibilities. Fourier analysis also allows the quantitative assessment of the reliability of such interpretation. The description of STIX data in terms of visibilities has a notable impact on the image reconstruction process, since it fosters the application of Fourier-based imaging algorithms.

Keywords

  1. spectrometer/telescope for imaging X-rays
  2. hard X-ray imaging
  3. Fourier analysis
  4. Moiré pattern

MSC codes

  1. 65T40
  2. 68U20
  3. 65Z05

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Information & Authors

Information

Published In

cover image SIAM Journal on Imaging Sciences
SIAM Journal on Imaging Sciences
Pages: 1315 - 1331
ISSN (online): 1936-4954

History

Submitted: 22 December 2014
Accepted: 13 April 2015
Published online: 11 June 2015

Keywords

  1. spectrometer/telescope for imaging X-rays
  2. hard X-ray imaging
  3. Fourier analysis
  4. Moiré pattern

MSC codes

  1. 65T40
  2. 68U20
  3. 65Z05

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