الملخص

ABSTRACT The aim of this work is to study some fundamental of tracks experimentally and theoretically in the detector CR-39 of thickness 250 µm, A computer program (TRACK-TEST) was used for calculating track parameters. The results show that a maximum energy lost is occurred when the energy of alpha particles is about 1.5 MeV, The tracks tip for incident alpha energies 1 and 1.5 MeV appeared in a spherical phase which is called over etch step at etch time 2hr, while a sharp phase for energies 5.5,4.5,3.5,2.5 MeV was investigated, The maximum track depth was found experimentally is about (1.5)MeV, while the calculated value of this depth was found about (2.5)MeV.