Input electron optics for Mott detectors used in secondary electron magnetometry

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.