Nuclear stopping power: Coulomb scattering(assumed elastic At 100 kev an ion of 15 amu has velocit ≈106m/s! E. M This is 1000 times faster than speed of sound in solids So ion is far past nucleus before nucleus can displace in response to Coulomb force So nuclear scattering is not strong at high ion velocity There are also only significant inelastic collisions when ion slows down that transfer energy 3.155J/6.152J.2003q f b E1, M1 M2 q f b E1, M1 M2 F µ Q1Q2 r 2 Nuclear stopping power: Coulomb scattering (assumed elastic) q f b E1, M1 M2 So nuclear scattering At 100 keV an ion of 15 amu has velocity , vion ≈ 106 m/s! This is 1000 times faster than speed of sound in solids… So ion is far past nucleus before nucleus can displace in response to Coulomb force is not strong at high ion velocity; There are also only significant inelastic collisions when ion slows down. that transfer energy… 3.155J/6.152J, 2003 10