Novel Concept for Handling the Neutron Polarisation in the Instrument MAGIC

The instrument MAGIC is a neutron diffractometer for the European Spallation Source (ESS) at Lund, Sweden. The instrument is dedicated to studies of magnetic properties in both applied and purely fundamental systems, ranging from magnetic structure refinement to magnetic diffuse scattering from single crystals and powder samples.

The present design shows a novel concept for the handling of neutron polarisation, which will offer a superior figure of merit with very high degree of polarization P and high transmission and transport T of neutrons through its optical polarising elements and magnetic fields.

In the setup shown, the neutrons enter from the right-hand side and undergo magnetic fields generated by permanent magnets and coils in order to realize any desired polarization direction at the sample location indicated by the transparent cube in the centre. The scattered neutrons can be analysed within a wide angular range of about 120 degrees as defined by the opening angles of the two large bent magnets.