3He Neutron Spin Filters at the JCNS: Towards Wide-Angle Polarization Analysis and the Separation of Coherent/Incoherent Scattering from Non-Deuterated Biological Objects

A. Ioffe；E. Babcock；S. Mattauch；V. Pipich；A. Radulescu；M. S. Appavou

Chinese Journal of Physics

50卷2期（2012 / 04 / 01）

137 - 154

英文

Polarization analysis is an important technique for polarized neutron scattering as it is allowing to obtain the full information about the vector magnetization in the sample that is critically important for detailed understanding of physical properties of new magnetic materials. Here we compare some of the major considerations between two different methods for polarization analysis-supermirror based analyzers and polarized 3He neutron spin filters (3He NSF) to be used for wide-angle, high-divergence applications like high Q-range smallangle neutron scattering (SANS). We will present the state-of-the-art in-situ (or on-beam) 3He NSF avoiding the well-known problem of the time decay of 3He (and neutron beam) polarization. In the simplified 1-dimensional version polarization analysis allows for the separation of coherent and incoherent scattering, making it a potentially important technique for studies of non-deuterated biological objects that themselves produce unavoidable incoherent background because of a high hydrogen content. The power of the method will be demonstrated by experiments at biological samples, where the signal to noise ratio was increased by about a factor of 100 for high Q values above 0.1 Å^(−1).