New approach of modeling charged particles track development in CR-39 detectors A.A. Azooz a, * , D. Hermsdorf b , M.A. Al-Jubbori c a Department of Physics, College of Science, Mosul University, Mosul, Iraq b Dresden University of Technology, Dresden, Germany c Department of Physics, College of Education, Mosul University, Mosul, Iraq highlights  New modeling of ions track length evolution measured by different authors.  Ions considered are p, d, a, Li, B, C, N, O.  Equations obtained to describe L(t) and etch rate for all ions at wide energy range.  Equations obtained do not involve any free fitting parameters.  Ions range values obtained compare well with results of SRIM software. article info Article history: Received 13 June 2013 Received in revised form 14 August 2013 Accepted 26 August 2013 Keywords: CR-39 SSNTD Charged ions range abstract In this work, previous modeling of protons and alpha particles track length development in CR-39 solid state nuclear track detectors SSNTD is modified and further extended. The extension involved the ac- commodation of heavier ions into the model. These ions include deuteron, lithium, boron, carbon, ni- trogen and oxygen ions. The new modeling does not contain any case sensitive free fitting parameters. Model calculation results are found to be in good agreement with both experimental data and SRIM software range energy dependence predictions. The access to a single unified and differentiable track length development equation results in the ability to obtain direct results for track etching rates. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Experimental studies of charged particles track length in CR-39 detectors have received increased attention in recent years (Hermsdorf and Hunger, 2009; Zaki et al., 2005; Saad et al., 2012). This type of studies has become possible through the use of atomic force microscopy (AFM) (Vazquez-Lopez et al., 2007; Fragoso et al., 2007; Johnson et al., 2009), confocal microscopy (Fromm et al., 2000; Vaginay et al., 2001; Félix-Bautista et al., 2013) and lateral irradiation techniques to obtain the longitudinal track profile (Nikezic and Yu, 2003, 2004). In view of the absence of a complete analytical theory which can fully describe track formation and development against etching time under different etching condi- tions, empirical parameterization has become the second best alternative used to describe experimental results. The availability of track length and track profile data has served well in developing empirical models for this purpose. One such modeling has been presented in Azooz et al. (2012a). In this model, a tangent hyperbolic type function is used to describe the track lengtheetching time dependence. The model involved four free fitting parameters to describe alpha particles tracks. The model was extended to cover protons tracks (Azooz et al., 2012b). The model produces reasonable description of experimental data for particle energies up to 5 MeV. However, one limitation with this model is that its performance at higher energy values is not equally adequate. The main reason for this is attributed to the fact that the energy depen- dence of the first free fitting parameter in the model has been assumed to be linear. This parameter is directly related to the track length saturation value. A more recent compilation of experimental results indicates that although the linear energy dependence is approximately valid at energies below 5 MeV, marginal deviations from linearity start to take place at higher energy values. In this work, more suitable power law energy dependence is assumed. Furthermore, the model is further developed to describe * Corresponding author. E-mail address: aasimazooz1@yahoo.com (A.A. Azooz). Contents lists available at ScienceDirect Radiation Measurements journal homepage: www.elsevier.com/locate/radmeas 1350-4487/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.radmeas.2013.08.012 Radiation Measurements 58 (2013) 94e100