This study investigates the mechanisms underlying ultrafast cross-luminescence observed in BaF2 crystals doped with LaF3. We identified an ultrafast luminescent component with a decay time of approximately 150 ps, which emerges under excitation energies exceeding 24 eV as a novel radiative recombination process between electrons in the 5p core band of Ba2+ and holes in the 5p core band of La3+. Ab initio calculations support this hypothesis, showing that the energy levels of the core bands facilitate such transitions. The findings indicate that BaF2-LaF3 scintillators hold significant promise for applications in time-of-flight tomography.
@article{arxiv.2412.04303,
title = {Ultrafast core-to-core luminescence in BaF$_2$-LaF$_3$ single crystals},
author = {Roman Shendrik and Evgeny Radzhabov and Alexandra Myasnikova and Viktorija Pankratova and Anatolijs Šarakovskis and Alexander Nepomnyashchikh and Alexander Bogdanov and Veronika Gavrilenko and Vladimir Pankratov},
journal= {arXiv preprint arXiv:2412.04303},
year = {2025}
}