Toward the solution of the inverse problem in neutron reflectometry
Abstract
The authors show that the chemical depth profile of a film of unknown structure can be retrieved unambiguously from neutron reflection data by adding to the system a known magnetic layer. Three independent reflectivities are obtained by taking measurements with the sample magnetized in a magnetic field perpendicular to the surface and subsequently parallel to it, and using in the latter geometry neutrons polarized either in the direction of the field or opposite to it. The procedure consists of two steps. First, from the three reflectivities both the real and imaginary parts of the reflection coefficient of the unknown film are extracted within the framework of the rigorous dynamical theory. Second, the neutron scatteringlength density (and consequently the chemical depth profile) is obtained by a suitable numerical technique for the conventional Schroedinger inverse scattering problem. Computer experiments were conducted for selected cases: starting from the profiles the reflectivities were calculated in a limited range of q and then the original profiles were successfully recovered. The influence on the accuracy of the recovered depth profile of the counting statistics and the cutoffs at low and high q are discussed.
 Authors:
 Delft Univ. (Netherlands). Interfacultair Reactor Instituut
 Iowa State Univ., Ames, IA (United States). Dept. of Mathematics
 Argonne National Lab., IL (United States)
 Publication Date:
 Research Org.:
 Argonne National Lab., IL (United States)
 Sponsoring Org.:
 USDOE Office of Energy Research, Washington, DC (United States); National Science Foundation, Washington, DC (United States)
 OSTI Identifier:
 510293
 Report Number(s):
 ANL/MSD/PP87579
ON: DE97008114; CNN: Contract DMS9504611; TRN: 97:014508
 DOE Contract Number:
 W31109ENG38
 Resource Type:
 Technical Report
 Resource Relation:
 Other Information: PBD: Aug 1995
 Country of Publication:
 United States
 Language:
 English
 Subject:
 66 PHYSICS; NEUTRON DIFFRACTION; INVERSE SCATTERING PROBLEM; REFLECTIVITY; MAGNETIC FIELDS; COMPUTERIZED SIMULATION; COMPUTER CALCULATIONS; POLARIZATION
Citation Formats
Haan, V.O. de, Well, A.A. van, Sacks, P.E., Adenwalla, S., and Felcher, G.P.. Toward the solution of the inverse problem in neutron reflectometry. United States: N. p., 1995.
Web. doi:10.2172/510293.
Haan, V.O. de, Well, A.A. van, Sacks, P.E., Adenwalla, S., & Felcher, G.P.. Toward the solution of the inverse problem in neutron reflectometry. United States. doi:10.2172/510293.
Haan, V.O. de, Well, A.A. van, Sacks, P.E., Adenwalla, S., and Felcher, G.P.. 1995.
"Toward the solution of the inverse problem in neutron reflectometry". United States.
doi:10.2172/510293. https://www.osti.gov/servlets/purl/510293.
@article{osti_510293,
title = {Toward the solution of the inverse problem in neutron reflectometry},
author = {Haan, V.O. de and Well, A.A. van and Sacks, P.E. and Adenwalla, S. and Felcher, G.P.},
abstractNote = {The authors show that the chemical depth profile of a film of unknown structure can be retrieved unambiguously from neutron reflection data by adding to the system a known magnetic layer. Three independent reflectivities are obtained by taking measurements with the sample magnetized in a magnetic field perpendicular to the surface and subsequently parallel to it, and using in the latter geometry neutrons polarized either in the direction of the field or opposite to it. The procedure consists of two steps. First, from the three reflectivities both the real and imaginary parts of the reflection coefficient of the unknown film are extracted within the framework of the rigorous dynamical theory. Second, the neutron scatteringlength density (and consequently the chemical depth profile) is obtained by a suitable numerical technique for the conventional Schroedinger inverse scattering problem. Computer experiments were conducted for selected cases: starting from the profiles the reflectivities were calculated in a limited range of q and then the original profiles were successfully recovered. The influence on the accuracy of the recovered depth profile of the counting statistics and the cutoffs at low and high q are discussed.},
doi = {10.2172/510293},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1995,
month = 8
}

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