Spherical neutron polarimetry applied to spin echo and time of flight spectroscopy

The changes in direction of the neutron spin that take place on scattering by a magnetic interaction vector are highly dependent on their relative directions. When the magnetic interaction vector is complex and or when there are nuclear magnetic interferences, the rotation of the incident polarisation can be of any angle around or toward a speci amp; 64257;c direction. In such circumstances, without zero amp; 64257;eld polarimeter, it is impossible to distinguish between a simple depolarisation and a rotation of the polarisation vector. Motivated by the investigation of chiral magnetic amp; 64258;uctuations, we have implemented the third generation zero amp; 64257;eld polarimeter Cryopad on the Neutron Spin Echo spectrometer SPAN at the HCB. We present the method and the limitations of this novel technique that is now available on IN15 at the ILL. The huge progress accomplished with 3 He neutron spin amp; 64257;lters amp; 64258;ippers are going to facilitate the exploitation of polarised beams at spallation sources. Zero amp; 64257;eld polarimeters like Cryopad are used routinely at several steady state sources but their design would be ine amp; 64259;cient at a pulse source. We have investigated the possibility to implement a zero amp; 64257;eld polarimeter on a time of amp; 64258;ight spectrometer. We propose a design that would lead to a better e amp; 64259;ciency and present the amp; 64257;nite element calculations