Radioluminescence and photoluminescence of Th:CaF2 crystals.
We study thorium-doped CaF2 crystals as a possible platform for optical spectroscopy of the (229)Th nuclear isomer transition. We anticipate two major sources of background signal that might cover the nuclear spectroscopy signal: VUV-photoluminescence, caused by the probe light, and radioluminescence, caused by the radioactive decay of (229)Th and its daughters. We find a rich photoluminescence spectrum at wavelengths above 260 nm, and radioluminescence emission above 220 nm. This is very promising, as fluorescence originating from the isomer transition, predicted at a wavelength shorter than 200 nm, could be filtered spectrally from the crystal luminescence. Furthermore, we investigate the temperature-dependent decay time of the luminescence, as well as thermoluminescence properties. Our findings allow for an immediate optimization of spectroscopy protocols for both the initial search for the nuclear transition using synchrotron radiation, as well as future optical clock operation with narrow-linewidth lasers.
TU Wien, Institute for Atomic and Subatomic Physics, 1020 Vienna, Austria.|Vienna Center for Quantum Science and Technology, Vienna, Austria.
Simon
S
Stellmer
TU Wien, Institute for Atomic and Subatomic Physics, 1020 Vienna, Austria.
Matthias
M
Schreitl
TU Wien, Institute for Atomic and Subatomic Physics, 1020 Vienna, Austria.
Thorsten
T
Schumm