Numerically and Experimentally Evaluation of Alpha Particle Track Parameters in CR-39 Nuclear Track Detectors

The use of our optimum new etching condition (Ashry et al., 2014) was involved in the current experiments. 252Cf and 241Am sources were used for irradiating samples of CR-39 solid state nuclear track detectors (SSNTDs) with fission fragments and alpha particles in irradiation chamber at normal temperature and different air pressure. The normal alpha tracks parameters of energies in the range of 1.0 to 5.0 MeV have been studied. The absorption of alpha particles in air has been studied through a set of experiments in which energy-range data were used to produce energy-distance curves for alpha particles in different air pressure. The rate of energy loss (dE/dx) has been measured experimentally and calculated using a numerical approach. In this approach, the SRIM-2003.26 and Matlab programs were used to calibrate the residual particle energy under different pressure conditions. From fission and alpha track diameters, the value of bulk etching rate was measured. The sensitivity was found to vary with alpha energy from 1.0 to 5.0 MeV. Both the critical angle (θc) and etching efficiency (η) of CR-39 detectors have been determined. A comparison between the measured results and calculated values is given and a good agreement has been found. Results can be successfully applicable in alpha autoradiography studies and detector efficiency determination for track registration in CR-39 plastic detectors at different air pressure