The SMC muon beam polarimeter

A muon beam polarimeter has been built for the SMC experiment at the CERN SPS, for muon energies of 100 to 200 GeV. The beam polarisation is determined by two methods, from the shape of the decay in flight positrons energy spectrum and from the asymmetry in the elastic scattering off polarised electrons of a magnetised ferromagnetic target whose magnetisation is reversed. The first method gives a typical polarisation of -0.8 with a relative systematic accuracy of 2.5%, the second one is expected to achieve a relative systematic accuracy of 2%. copyright 1995 American Institute of Physics