PolarBATS

Towards polarization analysis in high-resolution neutron backscattering spectroscopy

01/10/2025 to 30/09/2028

Polarization analysis is currently being established as a new technique in neutron spectroscopy at various large research facilities. This technique makes it possible to distinguish spin-incoherent neutron scattering from coherent scattering and thus, for example, to distinguish collective dynamics from so-called self- dynamics at the atomic level. However, there are currently no approaches to using this technique to achieve energy resolutions of significantly better than 10 microelectronvolt full width at half maximum. The current project therefore aims to significantly improve the energy resolution in polarized neutron spectroscopy. To this end, the uniaxial polarization of the neutron beam impinging on the sample is to be fully established at the IN16B neutron backscattering spectrometer at the Insitut Max von Laue-Paul Langevin in Grenoble. In addition, the polarization analysis after scattering on the sample is to be developed using a test setup to such an extent that an optimal solution for this challenge in the backscattering geometry can be determined. This solution will initially be established for the hybrid time-of- flight mode BATS at IN16B and will thus also be available to the comparable spectrometer MIRACLES at the European Spallation Source ESS. In the next step, a solution for the mode with even higher energy resolution using a Doppler monochromator will be sought.