The high-intensity hyperon beam at CERN

Abstract A high-intensity hyperon beam was constructed at CERN to deliver Σ − to experiment WA89 at the Omega facility and operated from 1989 to 1994. The setup allowed rapid changeover between hyperon and conventional hadron beam configurations. The beam provided a Σ − flux of 1.4×10 5 per burst at mean momenta between 330 and 345 GeV/ c produced by about 3×10 10 protons of 450 GeV/ c . At the experiment target the beam had a Σ − /π − ratio close to 0.4 and a size of 1.6×3.7cm 2 . The beam particle trajectories and their momenta were measured with a scintillating fibre hodoscope in the beam channel and a silicon microstrip detector at the exit of the channel. A fast transition radiation detector was used to identify the pion component of the beam.