Basic study of Europium doped LiCaAlF6 scintillator and its capability for thermal neutron imaging application

Eu2+ 0.1, 0.5, 1, and 2 mol% doped LiCaAlF6 single crystalline scintillators were grown by the micro-pulling down (mu-PD) method. Eu2+ 2 mol% doped LiCaAlF6 was also prepared using the Czochralski method. In the transmittance spectra, 4f-5d absorption lines appeared around 200-220 and 290-350 nm. An intense emission at 375 nm due to Eu2+ 5d-4f transition was observed under Am-241 alpha-ray excitation. When Cf-252 excited pulse height spectra were measured, Eu 2% doped one showed the highest light yield of 29,000 ph/n with 1.15 mu s decay time. Using the 2 inch phi Czochralski grown one coupled with the position sensitive photomultiplier tube covered by Cd mask with various size (1, 2, 3, and 5 mm) pin holes, thermal neutron imaging was examined. As a result, the spatial resolution turned out to be better than 1 mm. (C) 2011 Elsevier B.V. All rights reserved.