New POLDI _ project of reincarnation of a polarized neutron diffractometer at the reactor PIK

International Conference on Polarised Neutrons for Condensed Matter Investigations

Zobkalo, I.^1,2 ; Gavrilov, S.^1 ; Matveev, V.^1 ; Fenske, J.^3

Condensed State Research Department, Petersburg Nuclear Physics Institute, National Research Centre, Kurchatov Institute, Orlova Roshcha, Gatchina, 188300, Russia^1

Physical Department, Saint-Petersburg State University, Ulyanovskaya 3, St-Petersburg

198504, Russia^2

Zentrum fur Material und Kustenforschung GmbH, Helmholz-Zentrum Geesthacht, Max-Planck-Straße 1, Geesthacht

21502, Germany^3

关键词: Flexible construction;    Flipping ratios;    Magnetic form factor;    Polarization degree;    Polarized neutrons;    Sample position;    Spherical neutron polarimetry;    Wavelength ranges;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/862/1/012031/pdf
DOI  :  10.1088/1742-6596/862/1/012031

来源: IOP

【 摘 要 】

The project of a considerable modernization of the polarized neutron diffractometer POLDI is discussed. It assumes the adoption of POLDI to a broader range of magnetic investigations such as determination of magnetic structures, detailed investigation of complex magnetic structures, studies of magnetic domains, study of the magnetization density maps, magnetic form-factor particularities, local susceptibility, etc. The flexible construction should permit to use either spherical neutron polarimetry technique or flipping ratio technique. Different types of polarization system were analyzed. Original focusing fan-like bender is proposed as polarizer unit. Our simulations give evidence that for the wavelength range 1.3 - 3 Å and with suitable size, such a device can give much better efficiency than3He cells, which are often in use. The higher flux at the sample position of a factor of at least 3.3, with lower divergence and good polarization degree from 98% (1.3 Å) to above 94% (3 Å) makes the bender set-up favorable over the layout with a3He-cell.