Test of a two dimensional neutron spin analyzer

The aim of this measurement was to test the new large area spin polarization analyzer for the EVA SERGIS beamline at ILL Institute Laue Langevin . The spin analyzer, which was built in Berlin.selects one of the two spin states of a neutron beam of wavelength 5.5 impinging on a horizontal sample and reflected or scattered from the sample. The spin is analyzed for all neutrons scattered into a detector with an area of 190mm x 190mm positioned 2.7m behind the sample, thus covering an angular interval of 4 deg x 4 deg. The tests were done at the HMI V14 beamline followed by tests at the EVA beamline at ILL. The transmission for the two spin components, the flipping ratio and small angle scattering were recorded while scanning the incoming beam on the analyzer. It was clearly visible, that due to the stacked construction the intensity is blocked at regular intervals. Careful inspection shows that the transmission of the good spin component is more than 0.72 for 60 percent of the detector area and the corrected flipping ratio is more than 47 for 60 percent of the detector area. Although some small angle scattering is visible, it is notable that this analyzer design has small scattering intensitie