Experimental and theoretical study of the energy loss of C and O in Zn

Abstract

We present a combined experimental-theoretical study of the energy loss of C and O ions in Zn in the energy range 50-1000 keV/amu. This contribution has a double purpose, experimental and theoretical. On the experimental side, we present stopping power measurements that fill a gap in the literature for these projectiletarget combinations and cover an extended energy range, including the stopping maximum. On the theoretical side, we make a quantitative test on the applicability of various theoretical approaches to calculate the energy loss of heavy swift ions in solids. The description is performed using different models for valence and inner-shell electrons: a nonperturbative scattering calculation based on the transport cross section formalism to describe the Zn valence electron contribution, and two different models for the inner-shell contribution: the shellwise local plasma approximation (SLPA) and the convolution approximation for swift particles (CasP). The experimental results indicate that C is the limit for the applicability of the SLPA approach, which previously was successfully applied to projectiles from H to B. We find that this model clearly overestimates the stopping data for O ions. The origin of these discrepancies is related to the perturbative approximation involved in the SLPA. This shortcoming has been solved by using the nonperturbative CasP results to describe the inner-shell contribution, which yields a very good agreement with the experiments for both C and O ions. The study of the energy loss of ions in solids is a problem of interest for basic and applied research in many areas, such as ion implantation, radiation damage, and space research. Although a large number of experiments and calculations have been produced over the years, there is a demand for new data for various projectile-target combinations. Additionally, the development of a consistent theoretical framework is a subject of great current interest [1,2]. In recent years, we have performed a set of studies that combine experimental and theoretical research with the aim of providing a theoretical framework that could serve as a basis for more accurate predictions of the energy loss of swift ions in various solid materials. It is worthwhile to mention that for ions heavier than Li, the experimental stopping power data are scarce except for some particular materials (C, Al, Si, Ag, Au) [3]. In zinc, no energy loss measurements for C and O ions have been reported in the literature.In previous papers, we have studied in a systematic way the stopping coefficients for a series of ions of increasing atomic numbers: H, He, Li, Be, and B in zinc [4][5][6][7][8], and with our theoretical formulation, we have been able to explain changes in the stopping power curves, reaching a very good agreement between the experimental and theoretical results. This agreement was achieved by a detailed theoretical study of the contribution of each individual charge state of the projectile and each electronic shell of the target. This was made by separ...

New results about stopping power for positive ions: Experiment and theory

“…5 valence electrons (SLPA ii for the bound and EFSR-TCS iii for the valence electrons), and good agreement was found between theory and experiment. Recently, they extended their work to C and O ions 19 . But here, the perturbative SLPA calculation for inner shells that had been satisfactory for ions from H to B, was found too high; however, using the non-perturbative CasP iv theory due to Schiwietz and Grande 20 for the inner shells yielded approximate agreement v (see Fig.…”

“…The stopping power of Zn for O ions, as measured by Cantero et al19 ., compared to different theoretical formulations from the same paper, and to CasP and SRIM.They used different descriptions for inner shell and…”

Highly accurate nuclear and electronic stopping cross sections derived using Monte Carlo simulations to reproduce measured range data

“…Recent studies on the slowing-down of energetic ions in matter have addressed a wide variety of topics. Arranged roughly in the order of increasing projectile energy or velocity, noteworthy examples include the following: the correlation between electronic stopping and ion induced electron emission [1,2,3], the role of s and d electrons in electronic stopping of slow protons and deuterons [1,4,5,6,7], systematic differences in electronic stopping of low-energy H + and He + ions [6,8], the importance of exact knowledge of nuclear stopping (screening length) in low-energy ion scattering [9], the applicability of the reciprocity approach [10] for predicting ranges of slow heavy ions in compounds [11,12,13], modelling of range distributions in crystalline silicon [14], and measurements and interpretation of electronic stopping of low-and medium-mass ions in solids at energies around the Bragg peak and below [15,16,17]. However, reasonably accurate knowledge of electronic stopping cross sections S e is still available merely for a very limited number of projectile-target combinations, often within narrow ranges of energy.…”

Energy loss of light ions (H+ and He+) in matter: high accuracy measurements and comparison with the FEG model

“…Two completely independent versions and able to fully describe the energy loss in perturbative approaches are known as Mermin Energy-Loss Function -Generalized Oscillator Strength (MELF-GOS) [89,90] and Shell Local Plasma Approximation (SLPA) [12,91].…”

“…Even though more than a century of extensive investigation has passed, the process of energy loss 3 still configures an active field in modern science and technological applications. Precise and quantitative measurements with ion beams are required in material science and engineering [9,10,11,12], medical physics (radiotherapy) [13], ion implantation and modification of materials [14], and also in practically all Ion Beam Analysis (IBA) techniques [15,16,17,18,19,20]. Current research may be divided in two main categories: i) measuring accurate and reliable stopping power data, and ii) improving fundamental physics models, in other words: stopping power is a prerequisite for precise validation of theoretical models.…”