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Figure 2

magnet geometry

Detail near the end of the second dipole showing decay electrons exiting the second dipole and hitting the collimator and quadrupole magnet

Here we show a close up of downstream end of dipole. Energetic decay electrons reach the end of the dipole and can be caught in a downstream collimator as shown. The collimator is sized such that very little energy makes it out the back of the collimator. In a later study, not yet done, outscattered particles from the collimator as well as the decay electrons which either miss the collimator or happen further downstream (e.g. in the quadrupole) will have to be passed again through the model to see where they end up. Through such iteration of the basic half cell shown we can estimate the equilibrium energy deposition in the muon storage ring arc.

For this toy model the dipole coil ends are not defined. In fact in a more complete model with coil ends defined significant care should be taken to shield the coil ends from backscatter albedo from the collimator. For the present toy model, collimator albedo gives a non-negligible contribution to the energy deposition at the magnet end. Also the quadrupole magnet show in the toy cell is greatly simplified. In practice even the non-superconducting coils for the quadrupole should be protected from direct irradiation.