A Magnetic Compound Refractive Lens for Focusing and Polarizing Cold Neutron Beams

Journal Article · Mon Jan 01 00:00:00 EST 2007 · Reviews of Scientific Instruments

DOI:https://doi.org/10.1063/1.2709844· OSTI ID:937518

Littrell, Ken ^[1]; te Velthuis, G. E. ^[2]; Fletcher, G. P. ^[2]; Park, S. ^[3]; Kirby, B. J. ^[3]; Fitzsimmons, M. R. ^[3]

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1. ORNL
2. Argonne National Laboratory (ANL)
3. Los Alamos National Laboratory (LANL)

Biconcave cylindrical lenses are used to focus beams of x rays or neutrons using the refractive properties of matter. In the case of neutrons, the refractive properties of magnetic induction can similarly focus and simultaneously polarize the neutron beam without the concomitant attenuation of matter. This concept of a magnetic refractive lens was tested using a compound lens consisting of 99 pairs of cylindrical permanent magnets. The assembly successfully focused the intensity of a white beam of cold neutrons of one spin state at the detector, while defocusing the other. This experiment confirmed that a lens of this nature may boost the intensity locally by almost an order of magnitude and create a polarized beam. An estimate of the performance of a more practically dimensioned device suitable for incorporation in reflectometers and slit-geometry small angle scattering instruments is given.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 937518
• Journal Information: Reviews of Scientific Instruments, Vol. 78, Issue 3; ISSN 0034-6748
• Country of Publication: United States
• Language: English