A HIGH ENERGY SMALL PHASE-SPACE VOLUME MUON BEAM

The design and performance of a high-momentum, small phase-space volume muon beam is described. The muons are photo-produced by the bremsstrahlung of electrons incident on a thick target. Pion contamination is reduced to 3 × 10-6 of the muon flux by a 5.5 m beryllium filter placed immediately after the target. The optical system has two stages of momentum analysis to give an almost dispersion free beam, and a final imaging stage to clean up the tails of the beam distribution. Standard BNL 8Q48 and 18D72 magnets are used throughout. At 10 GeV/c, the beam yields 1.0 × 105 μ±/sec in a phase-space volume of 3 × 10-3 cm2 · sterad and a momentum band of ±1.5%. © 1969.