Progress On The Neutrino Factory Target System Design

The baseline target system for a Neutrino Factory or Muon Collider is a free liquid-metal (mercury) jet inside a 20-Tcapturesolenoidmagnet.A peaksolenoidfieldof 15T at themercurytarget locationis beingconsideredasanalternative to simply the target system. The tapering field profile, from Bi = 15 −20-T down to Bf = 1.5 −2-T over distance zf −zi, is optimized to maximize the muon yield at 50 m downstream of the mercury target within a defined energy window. The axial magnetic field is specified analytically using a inverse-cubic form, and the off-axis field is computed from a series expansionbasedon axial derivation of the axialfield. Thesimulation is performed using the MARS15 code,and results of the dependenceof the muon yield on the field profile are discussed.