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Technische Universität München> Technische Universität MünchenHelmholtz-Zentrum Geesthacht> Helmholtz-Zentrum GeesthachtForschungszentrum Jülich> Forschungszentrum Jülich
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MLZ (eng)

Lichtenbergstr.1
85748 Garching

KOMPASS (under construction)

Cold three axes spectrometer with polarization analysis

KOMPASS scheme KOMPASS scheme

KOMPASS — the new three axes spectrometer (to-be) installed in 2013 is fully designed to work exclusively with polarized neutrons and to provide a zero-field 3D polarization analysis, complementary to the other three axes spectrometers at the FRM II. Typical applications are hence the investigations of complex and weak magnetic structures and dynamics. The instrument is located at the end position of the curved, cold neutron guide NL 1 in the neutron guide hall west. Serial cavities in the first part of the guide system provide a permanent high-polarized incident neutron beam. The parabolic focusing guide design before the monochromator further includes different guide front ends for an optimized energy- and Q-resolution, respectively. The focusing guide together with the variable double-focussing monochromator (and analyzer) provide a high neutron flux over a large dynamic range at a small sample volume and a superior energy resolution at the expense of a slightly reduced transverse Q-resolution. For measurements with high Q-resolution, or for the investigation of steep dispersion relations, the parabolic front ends can be exchanged for straight elements. Higher-order wavelength contaminations can be suppressed by an optional velocity selector in front of the monochromator. For sample positioning the sample table is equipped with motorized xy-stages and cradles. The spin state of the scattered neutrons is analyzed with a multi-channel polarizer situated between the analyzer and the detector.

Apart from a standard closed-cycle cryostat, the instrument will be equipped with a mini MuPAD and a 3rd generation ILL system CryoPAD for the neutron polarimetry.

Typical Applications

A selection of predestinated systems for the study of their spin dynamics and structures with polarized neutrons and neutron polarimetry are…

  • all types of weak magnetic orders;
  • complex (chiral) magnetic structures (e.g. rare-earths);
  • quantum effects associated with longitudinal magnetic excitations;
  • quantum critical fluctuations;
  • systems of reduced dimensions (e.g. thin films and multilayer structures);
  • multiferroic and magneto-electric materials;
  • high-TC-superconductors;
  • itinerant magnetic systems.

Instrument Scientists

Prof. Dr. Markus Braden (project leader)
Phone: +49 (0)221 470-3655
E-Mail:

Prof. Dr. Peter Böni (project leader)
Phone: +49 (0)89 289-14711
E-Mail:

Alexander Grünwald (instrument scientist)
Phone: +49 (0)89 289-10754
E-Mail:

Operated by

Uni Köln
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Publications

Find the latest publications regarding KOMPASS in our publication database iMPULSE:

impulse.mlz-garching.de

MLZ is a cooperation between:

Technische Universität München> Technische Universität MünchenHelmholtz-Zentrum Geesthacht> Helmholtz-Zentrum GeesthachtForschungszentrum Jülich> Forschungszentrum Jülich