6.0 MeV u-1 carbon ion (C6+ and C4+)-induced secondary electron emission from water vapour

Abstract

Theoretical calculations of the DDCSs were made for C6+ ions using the continuum distorted wave-eikonal initial state model (CDW-EIS) in its straight-line version of the impact parameter approximation, showing general good agreement with experimental data, except in the intermediate- and high-energy region. On the other hand, the single differential cross section (SDCS), which was obtained by integrating the measured DDCSs over the solid angle, showed fairly good agreement with the CDW-EIS in the low-energy region, while a significant discrepancy between the observed SDCS and the Rudd-model scaling can be seen,suggesting that a simple -scaling law (i.e. first Born approximation) is not applicable for bare projectiles such as C6+ ions. The SDCS of C4+ ions was observed to be smaller than that of C6+ ons by 50% in the low-energy region (due to the screening effect of its bound electrons in C4+ ions, which could be explained quantitatively by taking account