POLI-HEiDi: The new polarised neutron diffractometer at the hot source (SR9) at the FRM II—Project status

The project to upgrade the existing single-crystal diffractometer Heisses Einkristal Diffractometer (HEiDi) at FRM II with a polarised neutron option, enabling the investigation of magnetic ground states in single crystals has been ongoing since autumn 2004. After a detailed investigation of the possible options it has been decided to develop and rebuild the secondary spectrometer and keep the HEiDi monocromator. The new instrument has been named POLI-HEiDi as an abbreviation of Polarisation Investigator at HEiDi. Two different zero-field polarimeters will be made available for spherical neutron polarimetry, Cryoapad and MuPAD. Both, polarisation and analysis will be performed with polarised 3He spin filters. Several new and important components of the instrument have recently been commissioned. In this report we present these components and show how they fit with the design of the whole instrument.