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X-ray Phase-contrast imaging

Martin Bech

Universitetslektor

X-ray Phase-contrast imaging

Optimization of phase contrast imaging with a nano-focus x-ray tube

Författare

  • Hanna Dierks
  • Till Dreier
  • Robin Kruger
  • Martin Bech
  • Jesper Wallentin

Summary, in English

Propagation-based phase contrast imaging with a laboratory x-ray source is a valuable tool for studying samples that show only low absorption contrast, either because of low density, elemental composition, or small feature size. If a propagation distance between sample and detector is introduced and the illumination is sufficiently coherent, the phase shift in the sample will cause additional contrast around interfaces, known as edge enhancement fringes. The strength of this effect depends not only on sample parameters and energy but also on the experimental geometry, which can be optimized accordingly. Recently, x-ray lab sources using transmission targets have become available, which provide very small source sizes in the few hundred nanometer range. This allows the use of a high-magnification geometry with a very short source-sample distance, while still achieving sufficient spatial coherence at the sample position. Moreover, the high geometrical magnification makes it possible to use detectors with a larger pixel size without reducing the image resolution. Here, we explore the influence of magnification on the edge enhancement fringes in such a geometry. We find experimentally and theoretically that the fringes become maximal at a magnification that is independent of the total source-detector distance. This optimal magnification only depends on the source size, the steepness of the sample feature, and the detector resolution. A stronger influence of the sample feature on the optimal magnification compared to low-magnification geometries is observed.

Avdelning/ar

  • LU profilområde: Ljus och material
  • LTH profilområde: Nanovetenskap och halvledarteknologi
  • Synkrotronljusfysik
  • NanoLund: Centre for Nanoscience
  • Medicinsk strålningsfysik, Lund
  • LTH profilområde: Teknik för hälsa
  • X-ray Phase Contrast
  • LTH profilområde: Avancerade ljuskällor

Publiceringsår

2023-07

Språk

Engelska

Sidor

5502-5507

Publikation/Tidskrift/Serie

Applied Optics

Volym

62

Issue

20

Dokumenttyp

Artikel i tidskrift

Förlag

Optical Society of America

Ämne

  • Atom and Molecular Physics and Optics

Status

Published

Forskningsgrupp

  • X-ray Phase Contrast

ISBN/ISSN/Övrigt

  • ISSN: 1559-128X