Bridgman growth and site occupation in LuAG:Ce scintillator crystals

Պետրոսյան, Ա. Գ.; Ovanesyan, K. L.; Sargsyan, R. V.; Shirinyan, G.O.; Abler, Daniel; Auffray, E.; Lecoq, P.; Dujardin, Christophe; Pédrini, C.

doi:10.1016/j.jcrysgro.2010.07.042

Cited by 68 publications

(38 citation statements)

References 25 publications

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“…Details of the method and of applied growth conditions can be found in [8,15,16]. The samples for radiation tests were selected from crystal sections free of light scattering inclusions or facets and controlled under polarized light (MPS-2 microscope).…”

Section: Methodsmentioning

confidence: 99%

“…Our recent studies on Bridgman-grown crystals have shown that the light yield of LuAG:Ce can reach 26,000 ph/MeV (or comparable to that of LSO) if higher Ce concentrations are incorporated in optical quality crystals (the studied range was 0.1-0.55 at%) [7,8]. It was also shown that high Ce 3 þ concentrations could be accommodated in the lattice by larger extents of nonequivalent occupancies by Lu 3 þ for octahedral Al 3 þ sites (0.5-2.5 at% in un-doped LuAG [9][10][11] and up to about 5 at% in LuAG:Ce containing 0.7 at% of Ce 3 þ [8]). The obtained results have shown that LuAG:Ce can compete with presently used materials in a number of applications, including high energy calorimetry and medical imaging.…”

Section: Introductionmentioning

confidence: 99%

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Radiation hardness of LuAG:Ce and LuAG:Pr scintillator crystals

Derdzyan

Ovanesyan

Պետրոսյան

et al. 2012

Journal of Crystal Growth

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Radiation hardness of LuAG:Ce and LuAG:Pr scintillator crystals

Derdzyan

Ovanesyan

Պետրոսյան

et al. 2012

Journal of Crystal Growth

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“…[ 16 ] It was also noticed that Lu Al antisite defects (AD) can severely deteriorate the scintillation characteristics of LuAG:Ce single crystals by acting as shallow traps, thus delaying the energy transport to the Ce 3+ emission centers. [ 17 ] Therefore, extensive research has recently been aimed at the preparation of ceramic analogues, which are characterized by lower preparation temperatures, more uniform doping, and lower cost.…”

mentioning

confidence: 99%

Towards Bright and Fast Lu₃Al₅O₁₂:Ce,Mg Optical Ceramics Scintillators

Liu

Mareš

Feng

et al. 2016

Advanced Optical Materials

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needed. Within the last two decades, a number of excellent scintillators based on Ce 3+ and Pr 3+ -doped materials, together with truly novel nanoscintillators, nanocomposites, and phase-separated material systems, have been discovered and studied in depth. [1][2][3][4][5][6][7][8] This high R&D activity in the scintillator fi eld was triggered by the pressing needs of modern medical imaging and radiotherapy, of high-energy physics, homeland security, and environmental applications. Among them, Cedoped Lu 3 Al 5 O 12 (LuAG:Ce) aluminum garnets have attracted much attention because of their relatively high density of 6.73 g cm −3 , 5d -4f electric dipole allowed radiative transition of Ce 3+ with emission at around 500-550 nm, fast scintillation response of about 60 ns, and high theoretical light yield (LY) value of 60000 photons/MeV. [ 9,10 ] It was found that LuAG:Ce single crystal containing 0.55 at% Ce 3+ ions prepared by Bridgman technique is a highly competitive scintillator displaying a LY of about 26000 photons/MeV with a shaping time of 1.5 μs, close to that of Lu 2 SiO 5 :Ce (LSO:Ce). [ 11 ] Based on the understanding of defect chemistry, an effective bandgap engineering approach was successfully applied to the LuAG system. Multicomponent garnets, featuring a balanced admixture of Gd and Ga cations in the Lubased garnet structure, form a new family of materials with an amazingly high light yield up to 58000 photons/MeV, a value exceeding that of the best Lu 2-x Y x SiO 5 :Ce (LYSO:Ce) materials by about 40%. [12][13][14][15] Therefore, oxides based on garnet structure are presently considered as competitive candidates for advanced scintillation applications.However, the low segregation coeffi cient of Ce 3+ ions in the LuAG lattice is detrimental for the growth of homogeneously doped large LuAG:Ce single crystals, especially for high Ce 3+ concentrations (Ce 3+ > 0.2 at%). [ 16 ] It was also noticed that Lu Al antisite defects (AD) can severely deteriorate the scintillation characteristics of LuAG:Ce single crystals by acting as shallow traps, thus delaying the energy transport to the Ce 3+ emission centers. [ 17 ] Therefore, extensive research has recently been aimed at the preparation of ceramic analogues, which are characterized by lower preparation temperatures, more uniform doping, and lower cost. One point to consider is that during The choice of sintering agent appears critical to achieve both high optical transparency and scintillation performance. In this work, the optical investigations coupled with X-ray absorption near-edge spectroscopy evidence the benefi cial role of MgO sintering agent. Mg 2+ co-dopants in ceramics drive the partial conversion of Ce 3+ to Ce 4+ . The Ce 4+ center, however, does not impair the scintillation performance due to its capability to positively infl uence the scintillation process. The importance of simultaneous application of such co-doping and annealing treatment is also demonstrated. With 0.3 at% Mg, our ceramics display a light yield of ≈25000 photons/MeV wit...

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“…The garnet compositions selected for the present studies were prepared by solid state reactions (Ar/H 2 , 1500C), melting in Mo crucibles (Ar/H 2 , melt soaking for 5 min, quenching at 100 deg/min) and by the vertical Bridgman method under conditions described in [14]. High-purity oxides of Lu 2 O 3 (99.99%), Al 2 O 3 (99.99%), Sc 2 O 3 (99.95%) were used in preparations.…”

Section: Methodsmentioning

confidence: 99%

“…This system is selected for studies because LuAG crystals doped with Ce 3 þ and Pr 3 þ ions demonstrate excellent scintillation properties [10][11][12][13][14] and the interest around these and related materials is rapidly increasing due to many potential applications in high energy physics and medical imaging. LuAG:Sc crystals with selective concentration of Sc can be used also as substrates for LPE of thin-disk lasers or thin scintillating films for high-resolution x-ray imaging to control the cell parameter mismatch between the film and the substrate.…”

Section: Introductionmentioning

confidence: 99%