FREIA

The challenges to be met in soft condensed matter and the life sciences are as wide ranging as the topics investigated. These include, but are not limited to:

• Self-assembly of surfactants, polymers and proteins at solid and liquid interfaces
• Rearrangement processes in thin films: e.g. polymer interdiffusion, inter-layer movement (e.g. lipid flip-flop), annealing/drying/exchange/wetting processes in composite films such as photovoltaic materials.
• Encapsulation and release of components in e.g. plastics, polymer blends, drug delivery and implant materials, chemical and biological sensors
• Switchable materials that undergo structural changes in response to external stimuli (chemical, mechanical, electrical or electromagnetic) with potential device applications
• Surface reactions that involve change in the film structure or chemical composition; e.g. enzyme catalysis, oxidation or other film degradation reactions, receptor-ligand binding, drug-target interactions, surface functionalisation etc.

Time-of-flight (tof) neutron reflectometry offers the possibility to record a range of Q-values simultaneously, allowing determination of both structure and chemical composition as a function of time. The key challenge lies in matching the time-resolution and the dynamic Q-range of the measurements to the time scales of the structural changes investigated. The key scientific drivers for FREIA are to allow fast kinetic measurements with the broadest possible simultaneous Q-range, and to provide high-throughput measurements across the scientific scope.

The instrument views the upper cold moderator and consists of a single elliptical guide, which is inclined at 2° below the x-axis and has its first vertical focal point in the cold moderator.

The guide has elliptical top/bottom faces while the horizontal guide with is constant at 4cm. The first 13m of the elliptical guide encloses a horizontal S-bender with 3 channels (m=3.2) and 130m radius of curvature. The elliptical guide and has a variable m-coating on the top and bottom faces varying from m=6 at the start/end to m=3 in the middle and back. The elliptical guide ends at 20m, and is followed by a 15cm gap for a solid-state silicon S-bender (upgrade option) for polarizing the beam, the collimation section. The 2m collimation section consists of interchangeable 3 guide sections, each designed to work with the polarized beam upgrade option:

1. three-slit package + fast shutters for kinetic measurements (guide split into 3 horizontal channels)
2. inverted geometry experiments using a deflection mirror (m=6) using the same slits as in 1
3. conventional collimation with a vertically absorbing guide between two slits

The detector, designed in-house at ESS is located at a fixed distance of 3 m from the sample and has 0.5 mm x 2.5 mm resolution on the 250 mm x 250 mm area.

Sample Environment

FREIA will have access to the common pool of sample-environment equipment provided by ESS.

Lead Scientist
Tom Arnold

Lead Engineer
Jon Elmer

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