Regensburg 2022 – scientific programme

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MA: Fachverband Magnetismus

MA 5: Magnetic Instrumentation and Characterization

MA 5.2: Talk

Monday, September 5, 2022, 09:45–10:00, H48

A cryogen-free 10T asymmetric neutron scattering magnet with 50mm sample space and temperature range from 300mK to 375K — •Tom Ritman-Meer, Marc Savey-Bennett, and Roger Mitchell — Cryogenic Ltd, 6 Acton Park Estate, The Vale, London, W3 7QE, United Kingdom

Cryogenic Ltd has built and delivered a Cryogen-Free ring-separated magnet for polarised neutron scattering experiments with 10T central field and integral VTI cooled from a single 1.8W cryocooler.

The magnet has a novel dual power-supply control unit to provide an asymmetric field when required, allowing the twin requirements of minimal depolarisation and maximum homogeneity to be managed. The magnet consists of inner and outer pairs which are separately controlled to minimise the impact of the asymmetry. The zero field point can be shifted by up to 20mm from the central plane.

The system has a sample space of 50mm diameter, housed within a closed-cycle refrigeration system, offering a temperature controlled environment of 1.5K-375K. Sample exchange is into an inner *static column* eliminating the risk of accidental blockage.

The system includes a specially designed helium-3 insert with >40mm working space inside an aluminium IVC of just 1mm thick allowing continuous operation at 280mK for 76 hours within the main VTI space. Total aluminium in the beam path is limited to just 15mm (sample to outer wall).

The system also includes an automated z-axis and rotation manipulator stage for both the He-3 unit and standard sample probes.