Overview of Polarized Neutron Sources

Polarized neutrons have applications in materials science and weak interactions studies. Several methods exist for polarizing neutrons, such as supermirrors for cold neutron energies, Heusler alloy for thermal neutron beams, and polarized proton filters for epithermal energies. While each of these devices are quite useful for different applications, there are also several applications that need a new method. After surveying the basic characteristics of these devices, this talk will focus on the present state of the art for neutron polarizers that are based on the large spin dependence of the cross section for neutron absorption by ³He. The status of applications to neutron scattering and fundamental physics will be also be discussed.