Focusing and imaging of cold neutrons with a permanent magnetic lens

Jay T Cremer Jr; Hanno Filter; Jürgen Klepp; Peter Geltenbort; Charles Dewhurst; Tatsuro Oda; Richard H Pantell

doi:10.1063/1.5116759

Focusing and imaging of cold neutrons with a permanent magnetic lens

Rev Sci Instrum. 2020 Jan 1;91(1):013704. doi: 10.1063/1.5116759.

Authors

Jay T Cremer Jr¹, Hanno Filter², Jürgen Klepp³, Peter Geltenbort⁴, Charles Dewhurst⁵, Tatsuro Oda⁶, Richard H Pantell⁷

Affiliations

¹ Adelphi Technology, Inc., 2003 East Bayshore Road, Redwood City, California 94063-4121, USA.
² Physics Department, Technical University Munich, Boltzmannstr. 2, 85748 Garching, Germany.
³ Faculty of Physics, University of Vienna, Boltzmanng. 5, 1090 Vienna, Austria.
⁴ Nuclear and Particle Physics Group, Institut Laue Langevin, 71 Avenue des Martyrs, CS 20156, F-38042 Grenoble Cedex 9, France.
⁵ Institut Laue-Langevin, B.P. 156, 38042 Grenoble Cedex 9, France.
⁶ Institute for Integrated Radiation and Nuclear Science Kyoto University, Kumatori, Osaka 590-0494, Japan.
⁷ Department of Electrical Engineering, Stanford University, 350 Serra Mall, Stanford, California 94305, USA.

PMID: 32012524
DOI: 10.1063/1.5116759

Abstract

This paper reports imaging of objects with slow neutrons, specifically very cold neutrons and cold neutrons, at Institut Laue Langevin, using novel, permanent magnet (Nd₂Fe₁₄B) compound refractive lenses (MCRL) with a large 2.5 cm bore diameter. The MCRL focuses and images spin-up neutrons and defocuses spin-down neutrons via a large, radial magnetic field gradient. A single lens neutron microscope, composed of an MCRL objective lens with 2-fold magnification, was tested using very cold (slow) neutrons at 45 Å wavelength. One-to-one imaging was obtained using 16.7 Å polarized neutrons. The magnetic field gradient of the MCRL was measured by raster-scanned pencil beams on D33. Finally, a compound neutron microscope was realized using an MCRL condenser lens, which provided increased illumination of objects, and an MCRL as objective lens to produce 3.5-fold magnification.