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Absorption, reflection as well as luminescence emission, excitation, and decay curves for single crystals of LuAlO 3 :Ce 3+ and LuAlO 3 :Pr 3+ grown by the Bridgman technique have been measured at various temperatures. The fluorescence spectra photo-excited over a wide energy domain ranging from the UV to the x-ray region, and the kinetics are typical of the cerium and praseodymium ions. These experimental results show that the exciton transfer to the dopant occurs at around 8 eV, and the energy transfer via sequential hole and electron trapping is dominant at higher energy. This process must be considered as the main scintillation mechanism in this crystal. The high efficiency of this mechanism is explained by the small energy difference between the 4f level of the dopant and the top of the valence band, estimated from XPS measurements.

The main objective of this contribution is to point out the potentialities of cerium doped LuAG single crystal as pixels and fibers. We first show that after optimization of growth conditions using Bridgman technology, this composition exhibits very good performances for scintillating applications (up to 26 000 photons/MeV). When grown with the micropulling down technology, fiber shapes can be obtained while the intrinsic performances are preserved. For the future high energy experiments requiring new detector concepts capable of delivering much richer informations about x- or gamma-ray energy deposition, unusual fiber shaped dense materials need to be developed. We demonstrate in this frame that cerium doped LuAG is a serious candidate for the next generation of ionizing radiation calorimeters.

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