RANGE PARAMETERS OF GOLD AND LEAD IN CARBON AND CARBON IN GOLD AT REDUCED ENERGIES OF 10(-3)LESS-THAN-EPSILON-LESS-THAN-1

Mean projected ranges and range straggling widths were determined for implants of Au and Pb into C at energies of about 1-1000 keV and for C into Au between 5 and 40 keV, The respective impurity depth profiles were obtained by backscattering of alpha-particles and the C-13(p, gam ma)-resonance reaction at 1.75 MeV. The range data of Au/C are about 1 0% higher than TRIM at LSS energies epsilon < 0.1, while somewhat lowe r values than predicted by TRIM are observed for Pb/C. At epsilon simi lar to 1 about 50% higher ranges are found for both systems. The strag gling widths grossly exceed TRIM estimates at all energies. In contras t, TRIM correctly predicts both range moments for the reverse system C /Au. The results are readily explained by ZI variations of nuclear sto pping at low energies and by reduced electronic stopping at high energ ies for Au/C and Pb/C, whereas correlation effects between the two sto pping mechanisms seem to be of minor importance. (C) 1998 Elsevier Sci ence B.V.