  Precise knowledge of all beam parameters is crucial to fully exploit the
physics potential of the International Linear Collider (ILC). A sufficiently
accurate measurement of the beam polarisation can only be achieved using
dedicated high energy Compton polarimeters combined with well-designed arrays
of Cherenkov detectors. This note focuses on the design and detailed simulation
of a suitable Cherenkov detector prototype and provides an overview of first
results from a highly successful beam test period.
