DOI: 10.1051/jp2:1994134
J. Phys. II France 4 (1994) 367-376

Resonantly enhanced neutron intensity in a surface segregated polymer blend

L.J. Norton¹, E.J. Kramer¹, R.A.L. Jones², F.S. Bates³, H.R. Brown⁴, G.P. Felcher⁵ and R. Kleb<sup>5

1</sup>  Department of Materials Science and Engineering and the Materials Science Center, Cornell University, Ithaca, NY 14853, U.S.A.
²  Cavendish Laboratory, Madingley Rd., Cambridge, CB3 0HE, U.K.
³  Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, U.S.A.
⁴  IBM-ARC, 650 Harry Road, San Jose, CA 95120, U.S.A.
⁵  Materials Science Division, Argonne National Laboratory, Argonne, IL 60439, U.S.A.

(Received 14 October 1993, accepted 10 November 1993)

Abstract
We have formed a resonant cavity for a massive particle, the neutron, in an attractive potential between a surface segregated polymer film and its substrate. Standing waves occur when incident waves interfere with the waves reflected from the substrate. Multiple internal reflections lead to an enhanced intensity at resonant wave vectors below the wave vector for total reflection. At these resonant wave vectors the enhanced neutron intensity incoherently scatters from the hydrogen containing polymer of the potential well causing a marked decrease in the reflectivity. The position of the resonant dips provides an aid to fitting the reflectivity data by restricting the possible scattering length density profiles. This phenomena may find application in the study of in-plane correlations by enhancing off-specular scattering.

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