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KOMPASS (in commissioning)
Cold three axes spectrometer with polarisation analysis
This instrument is focussed on cold neutrons. All parameters given here are valid during the current operation of FRM II. Please get in touch with the instrument team well in advance for all further details (length of experiment etc.).
KOMPASS — the new cold neutron three axes spectrometer 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 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-focusing 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 set of Helmholtz coils for longitudinal polarization analysis and the 3rd generation ILL system CryoPAD for the neutron polarimetry.
Construction and commissioning of KOMPASS are supported by the BMBF through project 05K19PK1.
Please note: With thermal neutrons, KOMPASS will be mainly operated in polarized neutron diffraction mode with longitudinal polarization analysis.
Prof. Dr. Markus Braden (project leader)
Phone: +49 (0)221 470-3655
Prof. Dr. Peter Böni (project leader)
Phone: +49 (0)89 289-14711
Dr. Dmitry Gorkov (instrument scientist)
Phone: +49 (0)89 289-10754
Phone: +49 (0)89 289-14879
Find the latest publications regarding KOMPASS in our publication database iMPULSE: