High-intensity hyperon beam at CERN

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 1.4×105 per burst at mean momenta between 330 and 345 GeV/c produced by about 3×1010 protons of 450 GeV/c. At the experiment target the beam had a Σ-/π- ratio close to 0.4 and a size of 1.6×3.7 cm2. 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.