Study of the Parameters Etch Rates (Bulk, Track and Ratio) for Alpha Particles in CR-39 Detector

In order to obtain tracks longitudinal profiles at different alpha particle energies and etching times, (1x1cm2) 200 mm thick CR-39 detectors made by Page Moldings (Pershore) UK were exposed to alpha radiation from an 241Am for about ten minutes. Distances between the source and detector corresponding to tentative alphaparticle energies of (2.38,2.92, 3.14 and 3.91) MeV. The exposure system involves narrow collimation in order to obtain almost perpendicular incidence angle. The detectors are sharply broken at the small 1 mm2 exposed area to expose the maximum number of tracks longitudinally. The samples were etched for a periodic time at 0.25h, using a sodium hydroxide solution NaOH with a concentration of 6.25N and temperature (701)0C. The optical microscope Made in Italy OPTIKA MICROSCOPE ITALY, which is connected with a digital camera type (MDCE-5C USB 0.2) and is connected to a personal computer(PC), this system used to observe and photographed the track profile formed in CR-39. The bulk etch rate, VB measured by thicknesses removed method of CR-39 nuclear track detector and its found VB=1.29m/h. Also, the track depth measured as a function of the etching time, the growth track rate as function of removed layers and etch rate ratio as function of residual range respectively.