6533b7d0fe1ef96bd125a163

RESEARCH PRODUCT

The3He neutron spin filter at ILL

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Abstract Neutron Spin-Filters (NSF) using gaseous polarized 3He have long been recognized as having enormous potential value in many polarized neutron scattering applications and, accordingly, ILL started a development program some years ago. This report gives an account of the present status of the project. Let us first briefly recall the reasons why the 3He-NSF is desirable as a generic polarization tool: Being a pure transmission device, NSF naturally decouples the neutron spin selection from other optical functions. Designing polarized instruments will be simplified having no geometrical constraints due to Bragg optics or beam deviation in the polarizer. Angular acceptance and energy band pass are much widened, making polarization handling much more compatible with focusing geometry and time of flight techniques. Gaseous NSF naturally achieves well-defined transmission functions. Quantitative interpretation of intensity measurements in polarization analysis mode will be much easier. Very homogeneous p...