Abstract
For several decades most of the efforts to develop
new scintillator materials have concentrated on high-light-yield
inorganic single-crystals while polycrystalline ceramic scintillators,
since their inception in the early 1980’s, have received
relatively little attention. Nevertheless, transparent ceramics offer
a promising approach to the fabrication of relatively inexpensive
scintillators via a simple mechanical compaction and annealing
process that eliminates single-crystal growth. Until recently,
commonly accepted concepts restricted the polycrystalline ceramic
approach to materials exhibiting a cubic crystal structure.
Here, we report our results on the development of two novel
ceramic scintillators based on the non-cubic crystalline materials:
LuSiO:Ce (LSO:Ce) and LaBr:Ce. While no evidence
for texturing has been found in their ceramic microstructures,
our LSO:Ce ceramics exhibit a surprisingly high level of transparency/
translucency and very good scintillation characteristics.
The LSO:Ce ceramic scintillation reaches a light yield level of
about 86% of that of a good LSO:Ce single crystal, and its decay
time is even faster than in single crystals. Research on LaBr:Ce
shows that translucent ceramics of the high-light-yield rare-earth
halides can also be synthesized. Our LaBr:Ce ceramics have light
yields above 42 000 photons/MeV (i.e., 70%of the single-crystal
light yield).
