Refractive and diffractive neutron optics with reduced chromatic aberration

Stefan Othmar Poulsen, Henning Friis Poulsen, P.M. Bentley

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Thermal neutron beams are an indispensable tool in physics research. The spatial and the temporal resolution attainable in experiments are dependent on the flux and collimation of the neutron beam which remain relatively poor, even for modern neutron sources. These difficulties may be mitigated by the use of optics for focusing and imaging. Refractive and diffractive optical elements, e.g. compound refractive lenses and Fresnel zone plates, are attractive due to their low cost, and simple alignment. These optical elements, however, suffer from chromatic aberration, which limit their effectiveness to highly monochromatic beams. This paper presents two novel concepts for focusing and imaging non-monochromatic thermal neutron beams with well-known optical elements: (1) a fast mechanical transfocator based on a compound refractive lens, which actively varies the number of individual lenses in the beam path to focus and image a time-of-flight beam, and (2) a passive optical element consisting of a compound refractive lens, and a Fresnel zone plate, which may focus and image both continuous and pulsed neutron beams.
Original languageEnglish
JournalNuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Volume767
Pages (from-to)415–420
ISSN0168-9002
DOIs
Publication statusPublished - 2014

Keywords

  • Neutron optics
  • Neutron imaging
  • Compound refractive lenses
  • Zone plates
  • Aberration
  • Microscopy

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