Optimizing Light Collection from Extractive Scintillating Resin in Flow-Cell Detectors

The objectives of this study were to investigate the changes in light collection efficiency for flow cell detector as various parameters are altered to find the optimum flow cell configuration. Columns with inner diameters of 0.16 cm, 0.48 cm, 0.79 cm, and 1.11 cm were packed with synthesized nonporous, un-functionalized beads to measure their detection efficiencies for solutions containing 210Po, 14C, or 90Sr/90Y. The average diameter of the beads used in the experiments was 147 µm ± 33 µm. The highest detection efficiency for 210Po was 15.3 ± 3.9% with the 1.11 cm diameter column. The 1.11 cm diameter column also yielded the highest detection efficiency of 29.6 ± 0.8% for 14C. When filled with a 90Sr/90Y solution, the 0.79 cm diameter column had the highest detection efficiency of 100 ± 7.0%. However, for both 14C and 90Sr/90Y, the 0.48 cm, 0.79 cm, and 1.11 cm diameter columns had detection efficiencies within 1-σ of each other. To investigate the effects of various parameters on the light collection efficiency and detection efficiency, models were built using GATE (GEANT4 Application for Tomographic Emissions) to simulate the columns. Bead diameter, column inner diameter, and source location were varied within the simulations, for beads that were arranged in a body-centered-cubic (BCC) configuration. The highest detection efficiency for 210Po was a point source located within each bead approximately 100 ± 1.3 %, regardless of column inner diameter or bead diameter. The same was found to be true for both 14C and 90Sr/90Y, wherein the point source configuration yielded the highest detection efficiencies of 93.1 ± 0.3% and 98.9 ± 0.2%, respectively, which were approximately equal regardless of bead or column size. These results suggest that if a porous resin were to be synthesized such that the radionuclide of interest could be trapped within a bead, high detection efficiencies could be achieved even with a column with a small inner diamete