Secondary-electron velocity spectra and angular distributions from ions penetrating thin solids☆

Abstract We present velocity spectra and angular distributions of secondary electrons emitted from cleaned surfaces of thin carbon and gold foils penetrated by H + ( E p = 0.8 and 1.2 MeV), H 2 + ( E p / M p = 0.8 MeV/u) and C + ( V p = 2.30− and 2.85 V B ). Prominent structures in doubly differential velocity spectra d 2 n/ d E d Ω of secondary electrons (SE) are (1) the “true SE” peak at low electron energies E e V e = 2 V p cos θ (observation angle θ), (3) convoy electrons at V e = V p ( θ = 0°), (4) loss electrons (from ions carrying electrons) at V e = − V p at θ = 180° (backward direction!), and (5) low-energy peaks ( E e