Measuring the initial electron beam polarizarion in e gamma collisions

The investigation of $e \gamma \to \nu W$ process is crucial for a possible high energy $e \gamma$ or $\gamma \gamma$ collider since it offers the possibility for both new physics discovery and precision measurements. The polarization of the initial beam is a limiting factor for the systematic errors in both cases. This note addresses the feasibility of making a measurement of the initial electron beam polarization with relative statistical error of one percent. Generator and detector level MC tools are used to obtain a realistic event selection for the signal process at the future CLIC test facility running at $ \sqrt{s}=150$ GeV.