Coloration-dependent correction for heavy ion measurements in an Al2O3:C,Mg-based fluorescent nuclear track detector

Abstract

To reduce or eliminate fluctuations in fluorescence intensity due to optical absorption and spherical aberration of a focused laser beam, and variations in color center concentrations between individual Al₂O₃:C,Mg-based fluorescent nuclear track detectors (FNTDs), we adopted the intensities of F₂²⁺ (2 Mg) and F₂⁺ (2 Mg) color centers corresponding to green and near-infrared (NIR) colorations, respectively. These intensities were used to develop coloration-dependent correction methods to improve accuracy of the FNTD-based heavy ion measurements. The FNTDs were irradiated with He, C, Ne, and Fe ions to prepare mono-energetic and multi-energetic specimens and then the performance of the correction methods was evaluated. Both the green and NIR coloration-dependent correction methods eliminated fluctuations in fluorescence intensity with depth, reducing the coefficient of variation (CV) by 36.6% and 35.9%, respectively. The green coloration-dependent correction method also reduced fluctuations of fluorescence intensity due to color centers by decreasing CV_w by 45.3%. The NIR coloration-dependent correction method was ineffective for correcting fluctuations due to color centers compared to the green coloration-dependent correction. The fluorescence intensities of He, C, and Fe tracks corrected by green and NIR colorations in the multi-energetic specimen coincided with those of mono-energetic specimens. Hence, these methods provide reliable and standardized approaches for heavy ion measurements and have the potential to be applied in determining the LET of heavy ions.