Experiments conducted on the LANL Trident two-beam facility show the viability of fluorescence-based imaging as a diagnostic in high-energy-density (HED) hydrodynamics experiments. Passive fluorescence experiments using titanium-pumped scandium-oxide, or iron-pumped manganese-oxide, show that fluorescence emission can be produced at sufficient intensities to be useful. Dynamic experiments, designed to demonstrate particle tracking in time for particle imaging velocimetry (PIV), were marginally successful in that only very large particulates could be definitively observed. However, our results indicate that experiments conducted on facilities offering a greater energy would be less susceptible to the limitations confronted in this study and thus, significantly enhance the prospect of PIV as an effective diagnostic tool in HED experiments.

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Abstract. Strontium iodide doped with europium [SrI 2 ðEu2þ Þ] is a new scintillator material being developed as an alternative to lanthanum bromide doped with cerium [LaBr 3 ðCe 3þ Þ] for use in high-energy astrophysical detectors. As with all scintillators, the issue of nonproportionality is important because it affects the energy resolution of the detector. We investigate how the nonproportionality of SrI 2 ðEu 2þ Þ changes as a function of temperature from 16 to 60°C by heating the SrI 2 ðEu 2þ Þ scintillator separate from the photomultiplier tube. In a separate experiment, we also investigate the nonproportionality at high energies (up to 6 MeV) of SrI 2 ðEu 2þ Þ at a testing facility located at NASA Goddard Space Flight Center. We find that the nonproportionality increases nearly monotonically as the temperature of the SrI 2 ðEu 2þ Þ scintillator is increased, although there is evidence of nonmonotonic behavior near 40°C, perhaps due to electric charge carriers trapping in the material. We also find that within the energy range of 662 keV to 6.1 MeV, the change in the nonproportionality of SrI 2 ðEu 2þ Þ is ∼1.5 to 2%. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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