Improvement of Makrofol® De 7-2 polycarbonate optical properties by thermal annealing for the registration of alpha particles

Translucent Makrofol (R) DE 7-2 polycarbonate samples are thermally-annealed at 200 degrees C for different durations in the air. UV-Vis spectra of the thermally-annealed Makrofol (R) DE 7-2 were measured. The results reveal that the light absorbance by thermally-annealed Makrofol (R) DE 7-2 is significantly minimized which enhances the visualization of the charged particle track registered on it. Both direct and indirect band gaps show pronounced stability over all thermal annealing durations; the same behavior was observed to Urbach's energy and the number of carbon atoms per cluster where no reasonable alteration was observed. The thermally-annealed Makrofol (R) DE 7-2 was irradiated with 3 MeV alpha particles and etched for different durations in 75% 6 N KOH + 25% C2H5OH at 50 degrees C. Alpha particle track diameter is found to be linearly correlated with the etching time up to 3 h before the Bragg peak. The chemical etching efficiency of alpha particle tracks ranges from 0.22 to 0.26. The current new findings indicate the possibility to improve the optical properties of translucent Makrofol (R) DE 7-2 by a thermal annealing for its utilization in charged particle registration. (C) 2016 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).