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Figure 1

magnet geometry

Plan view (XZ) of toy model geometry showing half cell with back-to-back 5 m dipoles, collimator and quadrupole magnet

Here we show the magnet geometry and tracks projected on to the X-Z plane at Y=0 for the toy model configuration. In this model we have two 5 m dipoles placed end to end followed by a copper collimator and a quadrupole magnet. The primary muon has 50 GeV. Muon decays take place randomly along the design orbit with decay electrons (green) bent to the ring inside.

Note that while some of the lowest energy electrons hit the inner vacuum chamber wall and shower, many decay electrons reach the collimator downstream of the dipoles. The showers from these decay electrons which hit the outer beam pipe are pretty much contained in the fiducial volume of the dipole warm iron yoke and there is very little backscatter which reaches the superconducting coils. The decay electrons, which suddenly find themselves in a 5 T field, emit synchrotron radiation photons (blue) which hit the outer vacuum beam pipe wall. While intercepting such photons at the vacuum beam pipe outer wall does not lead to energy deposition at the superconducting coil it is also possible to intercept these photons with an internal shield, as shown in Figure 8.