Muon Beams at the LAMPF Biomedical Channel

Modifications have been made to the LAMPF biomedical channel that allow the delivery of intense muon beams for physics experiments while retaining the design high-flux pion capability. Two types of muon beams have been developed: first, muons from the backward decay of pions and second, "cloud" muons, from the target region, momentum-degraded in the channel to reduce the pion component. Muons are collected from a region between the second and third bending magnets in the channel which can contain a Be degrader. A momentum-dispersed image is formed at a new downstream slit which is used to determine the momentum spread of both types of muon beams. The decay beam provides good polarization and low electron contamination. The degraded beam has higher intensity but about 40% electron contamination. Both beams have a pion contamination of about 3%.