Electronic stopping force of 12C, 28Si and 63Cu ions in HfO2 and SiO2 dielectric films

The stopping force of ions in matter is a basic physical concept that provides insight into the nature of ion-beam matter interactions. In applied research such as in nuclear analytical spectrometry the accuracy of stopping force data is crucial to the accuracy of analyses performed. The availability of ab initio calculations that can provide stopping force data with reasonable accuracy is a desirable development not only for ion beam analysis work and other applications that exploit the passage of energetic ions through matter, but also for fundamental ion-beam matter interaction studies. In this work stopping force measurements of 12C, 28Si and 63Cu ions through SiO2 and HfO2 dielectric films were carried out by time of flight spectrometry and the results are compared with semi-empirical calculations by Ziegler’s Stopping and Range of Ions in Matter (SRIM) code, and ab initio calculations by Grande and Schiewietz’s Convolution approximation for swift Particles (CasP) code. Indications are that in the 0.1–1.0 MeV/u projectile energy range, while SRIM performs quite well for lighter ions, in the case of intermediate to heavy projectiles CasP is on par with, and promises to describe stopping more accurately than SRIM, possibly due to the former’s incorporation of charge exchange effects into total stopping.financial support from the National Research Foundation (NRF) of South Africa and the International Atomic Energy agency (IAEA)