TY - JOUR
T1 - 2 keV He and Ne ion scattering on a Cu(110) surface
T2 - Experiment vs simulation
AU - Houssiau, L.
AU - Bertrand, P.
PY - 1994/5/2
Y1 - 1994/5/2
N2 - Scattering experiments performed at 143° with a TOF-ISS system on a Cu(110) single crystal indicate the very different sampling depth of He ions as compared with Ne ions. The ISS polar scans measured with He ions show a high sensitivity to the bulk atomic rows of the single crystal, whereas the scans measured with Ne ions indicate a sensitivity to only a couple of atoms in the first atomic layers. In order to evaluate the depth sampled by the backscattered particles, ion trajectories have been calculated with the MARLOWE simulation code. With Ne, the simulation shows that backscattered particles arise only from the 4 first layers (5 Å), but with He ions, they come from at least 80 layers (100 Å). A detailed analysis of escaping trajectories indicates that the Ne projectiles are scattered from the first layers after short trajectories. On the other hand, helium trajectories are usually quite complex, due to the possibility to follow privileged directions (channels), so that the projectiles can scatter from deep layers. We see that, even at low energy, channeling may be the major contributor to the variations of the backscattered intensity.
AB - Scattering experiments performed at 143° with a TOF-ISS system on a Cu(110) single crystal indicate the very different sampling depth of He ions as compared with Ne ions. The ISS polar scans measured with He ions show a high sensitivity to the bulk atomic rows of the single crystal, whereas the scans measured with Ne ions indicate a sensitivity to only a couple of atoms in the first atomic layers. In order to evaluate the depth sampled by the backscattered particles, ion trajectories have been calculated with the MARLOWE simulation code. With Ne, the simulation shows that backscattered particles arise only from the 4 first layers (5 Å), but with He ions, they come from at least 80 layers (100 Å). A detailed analysis of escaping trajectories indicates that the Ne projectiles are scattered from the first layers after short trajectories. On the other hand, helium trajectories are usually quite complex, due to the possibility to follow privileged directions (channels), so that the projectiles can scatter from deep layers. We see that, even at low energy, channeling may be the major contributor to the variations of the backscattered intensity.
UR - http://www.scopus.com/inward/record.url?scp=4244126039&partnerID=8YFLogxK
U2 - 10.1016/0168-583X(94)95549-2
DO - 10.1016/0168-583X(94)95549-2
M3 - Article
AN - SCOPUS:4244126039
SN - 0168-583X
VL - 90
SP - 247
EP - 251
JO - Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
JF - Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
IS - 1-4
ER -