The principle of spin analysis by means of measurement of the spin dependent absorption of a polarized electron beam is presented. The spin dependent signal is enhanced relative to the spin averaged signal at an energy near which the secondary yield is unity. Both the collected charge method and the zero‐crossing method are described for situations where the polarization can and cannot be reversed. A statistical analysis of the uncertainty in the polarization determination by each method is given. Annealed, evaporated Au films are shown to be suitable for the detecting surface of this spin detector. The figure of merit is derived and found for Au films to be comparable to the very best Mott detectors, but the electron optical acceptance is smaller. The applications for which this simple compact spin detector are especially suited are discussed.