  Many methods now exist to prepare free electrons into orbital angular
momentum states, and the predicted applications of these electron states as
probes of materials and scattering processes are numerous. The development of
electron orbital angular momentum measurement techniques has lagged behind. We
show that coupling between electron orbital angular momentum and a spatially
varying magnetic field produces an angular momentum-dependent focusing effect.
We propose a design for an orbital angular momentum measurement device built on
this principle. As the method of measurement is non-interferometric, the device
works equally well for mixed, superposed and pure final orbital angular
momentum states. The energy and orbital angular momentum distributions of
inelastically scattered electrons may be simultaneously measurable with this
technique.
