Muon Shielding for a 500-GeV Neutrino Facility

The explicit problem considered is the amount and "shape" of muon shielding required for a neutrino experimental area operated with a primary proton beam of energy up to 500-GeV. Muon transport programs have been developed for NAL1 which permit the calculation of muon intensities within a semi-infinite homogeneous medium. Results of such a calculation for a neutrino facility indicate that an earth shield 1100 meters in length and 7 meters in radius is required to permit the use of a bubble chamber detector with a primary beam energy of 500-GeV. A new calculational method using only available programs is proposed which permits the quantitative estimation of the effect of a magnetized-iron deflector. Results from this technique show that a magnetized-iron block 1.5 meters in radius and capable of deflecting the highest energy muons by 22 mrad may permit the use of a shield which is adequate for bubble chamber operation but only 550 meters of earth in length at 500-GeV.