Scintillation mechanisms in cerium fluoride

Abstract

Ultraviolet photoelectron spectroscopy, optical transmission, fluorescence excitation spectroscopy, and time-resolved fluorescence spectroscopy are used to investigate the scintillation mechanisms of cerium fluoride (CeF3) and of lanthanum fluoride doped with cerium in concentrations between 0.01% and 50% mole fraction cerium. In LaF3:Ce the absorption of either optical or ionizing radiation directly or indirectly results in excitation of the Ce3+ 4f electron to the lowest 5d level followed by 5d~4f fluorescence at 284-300 nm. Whereas for optical excitation the fluorescence has a 20 ns decay time, for ionizing radiation there is an additional faster (2-10 ns) initial decay component. As the cerium concentration increases, an another band appears that partially absorbs the 284-300 nm emission and re-radiates it in a broad band peaking at 340 nm and having a longer (-30 ns) decay time. In the limit of 100% CeF3, radiation trapping is very pronounced. The additional absorption and emission bands present at large Ce concentrations are attributed to Ce3+ ions in perturbed sites. The relative efficiency for excitation of unperturbed and f.erturbed cerium sites via the Ce3+ 5d and 6s bands, --the F-2p valence band, and the Ce3+ or La+ 5p core levels are determined from fluorescence excitation spectra.

Fluorescence Processes and Scintillation of CeF3Crystal Excited by UV and X-Ray Synchrotron Radiation

“…2 the high energy (300 nm) fluorescence decays measured under 11V and X-ray excitations are pictured. It is clear that for the two samples "with defects" and "pure" an additional fast decay component is observed after excitation by ionizing radiation, as already often reported not only for CeF3 but also for Ce3 + in several other crystals and glasses (see [3] and references herein).…”

“…The scintillation properties of CeF 3 have been studied extensively and excellent reviews have been compiled very recently [2,3] containing many references. New contributions can be also found in this special issue [4] and in [5].…”

Synthesis and characterization of ultrafine CeF3 nanoparticles modified by catanionic surfactant via a reverse micelles route

“…In contrast to normal CeF 3 NPs (curves c, d) with a diameter of about 16 nm, the modified CeF 3 NPs have a broader excitation range (curve a) and the peak position of excitation and emission has a red shift of 17 and 18 nm, respectively. Moreover, the red-shift in peak position is 19 nm relative to that of CeF 3 NPs (size 15-20 nm) prepared by CTAB microemulsions [12] and 54 nm as compared to that of CeF 3 bulk materials [42]. Such great shift in the emission spectra can be ascribed to the effects of small size as well as chemical modification.…”

Crystal growth and scintillation properties of Cs3CeCl6 and CsCe2Cl7

“…Note that both materials show some overlap of emission and excitation bands, so that Ce 3 + emission may be reabsorbed by another Ce 3 + center. Materials with high Ce concentrations are known to have selfabsorption [16,17]. Scintillation decay profiles were measured and the curves of both Cs 3 CeCl 6 and CsCe 2 Cl 7 were fitted with a double exponential function with a primary component of 50 ns and a secondary component in the range of $200-300 ns, Fig.…”