Modes of energy deposition of atomic projectiles in matter

The energy dissipated by electronic collisions was measured for H, He, Li, N, Ne, Na, Ar, K, Rb, and Cs projectiles stopped in silicon crystals. Projectile velocities, v1, range between 0.29 v0 and 3.75 v0, where v0 = e2/Dirac constant = 2.18 x 108 cm/sec. The targets were silicon surface-barrier particle detectors which registered inherently the electronic excitation through the separation of electron-hole pairs. The difference between the total kinetic energy dissipated and the electronic energy losses measured through particle-hole pair production yields the energy dissipated in screened Coulomb collisions between the projectiles and the silicon atoms of the crystal lattice. The results follow the trends predicted by the theory of Lindhard, et al., for the stopping of slow heavy atomic projectiles in matter