Asterix

Surfaces and Interfaces

Asterix is a polarized neutron beam spectrometer for neutron reflectometry and diffraction experiments with polarization analysis.  An unpolarized beam option is available.  The attendant research program primarily involves studies of magnetic thin films, interfaces and nanostructures.  In addition, studies of single crystal and polycrystalline samples are also performed. Asterix is equipped with Helmholtz, electro- or superconducting magnets that routinely offer a range of magnetic fields up to 11 T (with polarization analysis).

Magnetic fields normally point in the vertical direction, while scattering is normally detected in the horizontal plane. Cryostats providing temperatures ranging from 1.6 K to a few hundred K are available and compatible with magnetic fields.  Asterix has a one-dimensional position sensitive detector covering a range of scattering angles up to 30º, and a two-dimensional position sensitive detector array covering scattering angles up to 120º.  The instrument views a coupled liquid hydrogen moderator providing neutrons in two wavelength bands of 2 to 9 Å or 4 to 13 Å. A 16 W 808 nm laser diode array is also available for illuminating samples during neutron scattering experiments.

The figure below shows a polarized neutron reflectometry measurement taken from a 1 cm² sample using a Displex cryostat.