Speaker
Description
Scintillators have long been powerful tools in radiation detection, however, cannot offer a practical alternative to solid-state detectors in conventional particle telescopes applied in spaceborne measurements of solar energetic particles. The two main reasons are related to the common experience of their poor energy resolution, and technological obstacles of producing thin-film scintillators that obey criteria for long-term stability and high luminescence yield.
The experimental goal of our work was to revisit the functional and stability concerns, and offer a novel solution for thin-film scintillators in order to be competitive with present detection techniques in the targeted energy range 1-100 MeV/nucleon. Our choice for scintillation material was copper-halide perovskites, which have been tested for ion-beam induced radioluminescence by characterizing their spectroscopic and timing performance. A simplified spray-deposition technique has also been developed to produce thin films on transparent substrates in the size range of 1-100 $\mu$m. The layers were built with a polycrystalline morphology intentionally avoiding subtle procedures of high-purity crystal growth, which had no deterioration effect on the luminescence behaviour due to the strong quantum confinement in the reduced-dimensional structure of copper-halide compositions, as well as the favorable reorganization of excitonic and surface trap states. The measured scintillation yield for the brightest $\mathrm{Cs_3Cu_2I_5}$ composition was nearly 30000 photons/MeV for electrons and 10000 photons/MeV for $\alpha$-particles, the FWHM energy resolution for 5 MeV $\alpha$-particles was 5.5%, and a net timing spread of $<$300 ps was found by using SiPM as photon detector.
The utilization of $\mathrm{Cs_3Cu_2I_5}$ thin films with a thickness optimized for simultaneous particle transmission and sufficient light production is proposed as an efficient $\Delta$E-detector in telescopes taking into account our findings of high radiation tolerance, weak temperature dependence of scintillation yield, and low fabrication costs in contrast to solid-state detectors. We have tested the scintillation performance of $\mathrm{Cs_3Cu_2I_5}$ thin films in a pilot telescope assembly using accelerated ion beams from protons to selected heavy ions. The characterization of the detector performance involving particle mass discrimination, trajectory reconstruction, and sensitivity limits will also be presented.
| Eligibility for "Best presentation for young researcher" prize | No |
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