Construction and start of operation of the single-crystal diffractometer with polarized neutrons POLI and implementation of the flipping ratio method at the hot source of the FRM II


The single-crystal diffractometer for polarized neutrons POLI was set up at its new measuring station at the beam channel SR-9a of the hot source of the FRM II and put into operation with new monochromators. A 3He polarizer for hot neutrons and a radial super-mirror polarizer for thermal neutrons designed for focusing geometry were developed and built, and both polarizers were put into operation on the two secondary beam channels of POLI. In addition, the infrastructure for the use of POLI was set up. All in all, the two single-crystal diffractometers HEiDi (SR-9b) and POLI (SR-9a) can be operated independently scientifically at the hot source. The single-crystal diffractometer POLI is equipped with zero-field 3D polarization analysis and is to be expanded for flipping-ratio measurements for the investigation of spin density with a vertical high-field magnet, which requires an asymmetrical magnetic field and a large vertical opening angle.

With the expansion of POLI, two measurement methods previously unavailable in Germany (zero field 3D polarization analysis for the determination of complex magnetic structures and the flipping-ratio method for the determination of spin densities) were established at the FRM II.


Prof. Dr. Georg Roth (Project manager)
Dr. Vladimir Hutanu (Project scientist)

  Copyright: © Bundesministerium für Bildung und Forschung


Bundesministerium für Bildung und Forschung
Project executing organization: Deutsches Elektronen-Synchrotron (PT-DESY)
Grant Nr. of the BMBF: 05K13PA3
Project period: 01.07.2013 – 31.12.2016