[log in to unmask]" type="cite">As I understand it (from Norman), multiple scattering will occur in the tracker and other geometry components, rather than single scattering. Though I would assume some single scattering will be invoked by the physics engine, this is not going to influence the primary e+e- events generated from target interactions, which are input externally. So the effect should be small/negligible. (Can we confirm this somehow?)