TY  - GEN
Y1  - 2013///
ID  - heidok15980
A1  - Rösch, Thomas Federico
TI  - Using the Blue/Green Emission in Fluorescent
Nuclear Track Detectors for Ion Beam Therapy
Research
N2  - For studies on the mechanisms of proton and ion radiotherapy it is necessary to have a detector able to quantify local energy deposition on nano- to micrometer scales. Fluorescent nuclear track detectors (FNTDs) based on biocompatible doped alumina single crystals fulfill these criteria. However, the concentration of fluorescent color centers can vary from detector to detector and even within the same sample. This can hamper severely the application of FNTDs. This work's purpose was therefore to investigate the relations between (usually used) red/near IR and (hitherto unused) blue/green fluorescence and corresponding color center concentrations and their influence on the detector sensitivity as well as to assess the feasibility of employing the blue-greenish fluorescence
(blue channel) for quantification and normalization. The study was mainly done on a set of 20 differently colored, hand-selected unirradiated FNTDs representing the span
of coloration found during the crystal growth process. We found out that is feasible to read out the blue channel consistently with our standard equipment. The blue/green
fluorescence before irradiation (and after until 10 Gy) is a good measure for the total color center concentration. Both the sensitivity and the background (before irradiation)
were found to correlate significantly with the blue signal after irradiation, allowing for normalization of intersample variability. We did not find saturation of blue signal for doses up to 10 kGy which might open the use of FNTD for high dose measurements. New laser dependent color center depletion was discovered with yet unclear implications for dosimetry. We also found that simple optical absorption measurements for coloration do not replace blue channel measurements.
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/15980/
AV  - public
ER  -