Performance of the High-Energy Pion Beam at LAMPF

The Los Alamos Clinton P. Anderson Meson Physics Facility (LAMPF) high-energy pion beam (P3) is a three-bend channel with two achromatic output legs designed for high-intensity and moderate resolution. The best resolution was measured to be 0.2% in Δp/ p. A phase space of about 25 π mr-cm is transmitted by the channel. A π+ flux of 2 × 107 pions/s was measured for 300 MeV/c momentum when a 7 μA proton beam struck a 6 cm graphite target. Proton contamination for good quality π+ beams up to 450 MeV is negligible when an energy degrader (graphite) is used to separate protons from pions. In actual operation, very little beam tuning is required. Focusing elements are set according to the TRANSPORT computer code. Additional rate and contamination data will be presented, as well as additional information gained from operating experience.