An electron spin polarization detector to be used in thin film and surface
magnetometry via secondary electron emission is described in detail. It con
sists of a Mott detector coupled to an input electron optic designed to imp
rove the overall efficiency of the system. This is achieved by taking full
advantage of the polarization increase for electrons emitted at low kinetic
energy, generally observed in ferromagnets. The input electron optic is ap
positely designed so as to operate as an energy low pass filter, which stro
ngly modifies the energy distribution of the secondary electrons collected
by the Mott detector. Ray tracing analysis indicates that the system perfor
mances are improved by more than a factor of 3 with respect to a bare detec
tor operating with an undistorted secondary electron spectrum. (C) 1998 Els
evier Science B.V. All rights reserved.