Grazing incidence neutron optics
AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorsMikhail V. Gubarev, Brian D. Ramsey, Darell E. Engelhaupt
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Abstract
Neutron optics based on the two-reflection geometries are capable of controlling beams of long wavelength neutrons with low angular divergence. The preferred mirror fabrication technique is a replication process with electroform nickel replication process being preferable. In the preliminary demonstration test an electroform nickel optics gave the neutron current density gain at the focal spot of the mirror at least 8 for neutron wavelengths in the range from 6 to 20 Å. The replication techniques can be also be used to fabricate neutron beam controlling guides.
Claims27
A method of fabricating a neutron mirror for use in an optical device for focusing a quasi-parallel beam of incident neutrons, said optical device including a source for said quasi-parallel beam of incident neutrons, comprising the steps of:
- a) fabricating a mandrel of the required shape;
- b) polishing said mandrel;
- c) forming a material onto said mandrel to form said mirror;
- said mirror being a conical section of revolution mirror including a figured inlet section at one end transitioning to a figured outlet section at its other end;
- the figures of said sections being different;
- said figures being described by equations selected from the group consisting of the second order of magnitude and approximations of the second order of magnitude;
- and
- d) separating said mirror from said mandrel:
- whereby, when said quasi-parallel beam of neutrons from said source is incident on said figured inlet section, a focal spot is spaced apart from said figured outlet section.
A method of fabricating a neutron mirror for use in an optical device for focusing a quasi-parallel beam of incident neutrons, said optical device including a source for said quasi-parallel beam of incident neutrons, comprising the steps of:
- a) fabricating a mandrel of the required shape;
- b) polishing said mandrel;
- c) electroforming a material with high neutron reflectivity onto said mandrel to form said mirror;
- said mirror being a conical section of revolution mirror and including a figured inlet section at one end transitioning to a figured outlet section at its other end;
- the figures of said sections being different;
- said figures being described by equations selected from the group consisting of the second order of magnitude and approximations of the second order of magnitude;
- and
- d) separating said mirror from said mandrel by differential thermal contraction:
- whereby, when said quasi-parallel beam of neutrons from said source is incident on said figured inlet section, a focal spot is spaced apart from said figured outlet section.
Dependencies are inferred from the claim text.