Raman and photoluminescence spectroscopy analysis of gamma irradiated human hair

Abstract

Preliminary study has been made of black human hair, carbon concentration of some 53%, a model in examining the potential of hair of the human head in retrospective and emergency biodosimetry applications, also offering effective atomic number near to that of water. The hair samples were exposed to ^{60}Co gamma rays, delivering doses from 0 to 200 Gy. Structural alterations were observed, use being made of Raman and photoluminescence (PL) spectroscopy. Most prominent among the features observed in the first-order Raman spectra are the D and G peaks, appearing at 1370 {{pm }} 18,{hbox {cm}}^{-1} and 1589 {{pm }} 11,{hbox {cm}}^{-1} respectively, the intensity ratio {{{I}}}_{{{D}}}{{/}}{{{I}}}_{{{G}}} indicating dose-dependent defects generation and annealing of structural alterations. The wavelengths of the PL absorption and emission peaks are found to be centred at 592.3 pm 12.5 nm and 1077.4 pm 7.3 nm, respectively. The hair samples mean band gap energy ({{{E}}}_{{{g}}}) post-irradiation was found to be 2.10 pm 0.04 eV, of the order of a semiconductor and approximately two times the {{{E}}}_{{{g}}} of other carbon-rich materials reported via the same methodology.