**6. Neutrino interaction model**

Neutrinos can interact directly with tissue or with intervening matter to produce charged particles that result in a biological detriment. The radiation environment is complex and simulations (e.g., Monte Carlo methods) can be used to model the dynamics of the neutrino interaction including the energy and angular dependence of each particle (e.g., *<sup>e</sup>* , *<sup>e</sup>* , , , , , e, μ, τ, and hadrons) involved in the interaction. Performing a neutrino simulation is too dependent on specific accelerator characteristics and will not add to the health physics presentation. Rather than performing a Monte Carlo simulation, we follow the analytical approach of Cossairt et al. (1997) and King (1999b) to quantify the neutrino effective dose. This approach is acceptable in view of the current uncertainties in muon collider technology and the nature of the neutrino interaction for both charged current (CC) and neutral current (NC) weak processes (King, 1999c).

Following King (1999c), the dominant interaction of TeV-scale neutrinos is deep inelastic scattering with nucleons that include CC and NC components. In the NC process, the neutrino is scattered by a nucleon (N) and loses energy with the production of hadrons (X) through a *N X* reaction. This NC reaction contributes about 25 percent of the total cross section. This NC process can be interpreted as elastic scattering off one of the quarks (q) inside the nucleon through the exchange of a virtual Z0 boson ( *q q* ).

CC scattering is similar to NC scattering except that the neutrino is converted into its corresponding charged lepton (l). This includes reactions such as *NlX* and *NlX* where l is an electron/muon for electron/muon neutrinos. At the quark level, a charged W boson is exchanged with a quark to produce another quark (q′) whose charge differs by one unit through processes such as *q l q* and *q l q*.

The final state quarks produce hadrons on a nuclear distance scale that contribute to the effective dose. The CC and NC scattering processes are included in the Process A –D descriptions noted in previous discussion.
