Orateur
Dr
Vitalii Mikhailik
(Univ of Oxford)
Description
The multi-photon counting technique (NIMA, 553 (2005) 522) was essentially modified
to investigate scintillation characteristics of crystals at milli-Kelvin temperatures
using a 3He/4He dilution refrigerator. The temperature dependence of the
scintillation decay time and light yield of CaWO4 were measured down to 20 mK for the
first time. The scintillation light yield is found to be invariant below 10 K – a
tenet crucial to a decade of cryogenic scintillator experiments, yet previously
unproved. The temperature change of the decay kinetic of CaWO4 is analysed in terms
of a simple three-level model of the emission centre. The model agrees well with the
data over the temperature range (0.02-350 K) investigated, and is used to determine
the parameters of the relaxed excited state.
Author
Dr
Vitalii Mikhailik
(Univ of Oxford)
