Energy Loss and Straggling of Random and Channeled High-Energy Particles in Thin Targets

Abstract

When a charged particle traverses a foil, it interacts with the target constituents via its electromagnetic field. We shall here consider only electronic collisions leading to the excitation and ionization of the target atoms and to the well-known slowing-down of the projectile. We shall consider highly relativistic projectiles with velocity υ close to the speed of light, β ≡ υ/c ≃ 1. For very relativistic charged particles, the spherically symmetric Coulomb field, valid in the rest frame, is compressed in the longitudinal direction and elongated in the transverse due to the Lorentz transformation.