Evaluation and optimization of measurement conditions for heavy ions with fluorescent nuclear track detectors.

In applying fluorescent nuclear track detectors for heavy ion measurement, the fluorescence intensity directly influences linear energy transfer (LET) estimation. However, the conventional analysis highly depends on the analyzed depth and the reference frames from the optical readout. To improve the accuracy of measurements of heavy ions, the gradient of intensity and moving average fluorescence intensity were acquired and calculated to optimize the measurement conditions. The results indicate that the intensity gradient is an alternative quantity to discriminate ions with different LET, and the moving average fluorescence intensity is readily differentiated among individual ions without overlapping values in fluorescence intensity. The scanned range of 25-45 μm is suggested to be the most suitable depth for measurement. To exclude the impact of the variation in fluorescence intensity on evaluation, it is recommended to use the quantities calculated in moving averages with depth in the future.