Comparison of absorption, luminescence and scintillation characteristics in Lu1.95Y0.05SiO5:Ce,Ca and Y2SiO5:Ce scintillators

Chewpraditkul, Weerapong; Wanarak, Chalerm; Szczesniak, T.; Moszyński, M.; Jarý, V.; Beitlerová, A.; Nikl, M.

doi:10.1016/j.optmat.2013.04.024

Cited by 54 publications

(29 citation statements)

References 28 publications

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“…Similar spectral features have been revealed in diffuse reflectance spectra of powders of Ce 4 þ -doped A 2 ZrO 4 (A¼Sr, Ba) even much earlier [11]. Recently, high scintillation light yield has been reported in the Ce 4 þ -containing LYSO:Ce,Ca [12] and a new model of the Ce 4 þ involvement in scintillation mechanism of orthosilicate scintillators has been proposed in Refs. [13,14] consisting in (i) an immediate capture of electron from the conduction band by a stable Ce 4 þ center and (ii) radiative de-excitation of such a temporary Ce 3 þ which in the following final step (iii) captures a hole from the valence band to complete the cycle, returning into stable Ce 4 þ charge state.…”

Section: Introductionsupporting

confidence: 71%

The role of cerium variable charge state in the luminescence and scintillation mechanism in complex oxide scintillators: The effect of air annealing

Nikl

Babin

Mareš

et al. 2016

Journal of Luminescence

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a b s t r a c tThe influence of annealing in air at elevated temperatures on the absorption, luminescence and scintillation characteristics was studied for a set of Ce-doped aluminum garnet and perovskite single crystals. Positive effects consisting mainly in increase of light yield and decrease of afterglow were found to varying extent in all the materials. It is explained by the positive role of created stable Ce 4 þ center in scintillation mechanism and by decrease of deep trap concentration based on oxygen vacancies.

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Section: Introductionsupporting

confidence: 71%

The role of cerium variable charge state in the luminescence and scintillation mechanism in complex oxide scintillators: The effect of air annealing

Nikl

Babin

Mareš

et al. 2016

Journal of Luminescence

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“…This assumption is based on apparent similarities with Ca 2+ -codoped LYSO:Ce [37], and with Mg 2+ -codoped LuAG:Ce crystals [38]. In these studies, the bivalent-ion codoping changes the oxidation state of the cerium to the Ce 4+ .…”

Section: Discussionmentioning

confidence: 99%

Effect of oxidation annealing on optical properties of YAG:Ce single crystals

2015

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“…[ 30 ] A LY decrease for high Ca 2+ concentrations (0.1-0.4% in the melt) has also been reported in LYSO:Ce,Ca single crystals, [ 42,43 ] but the real concentration of the Ca co-dopant in this kind of crystals was measured as low as 60 ppm. [ 25 ] Even though our ceramics are more heavily doped, we expect that only a small fraction of the Mg ions diffuses into the grains and infl uences the scintillation, whereas the majority acts mostly as sintering aids between the grains. Moreover, phase separation may also occur for high doping concentrations.…”

Section: Full Paper Full Paper Full Papermentioning

confidence: 95%

“…[ 22,23 ] The presence of Ce 4+ centers in the LSO:Ce 3+ ,Me 2+ structure due to local charge compensation following Me 2+ co-doping was clearly be identifi ed by its charge transfer (CT) absorption located in the UV and considered responsible for the improved scintillation performance displayed by the material. [ 24,25 ] Participation of Ce 4+ in the scintillation process was suggested to occur also in sol-gel silica glasses. [ 26,27 ] In this case the presence of Ce 4+ is related to the oxidizing atmosphere during the glass synthesis rather than to a co-doping effect.…”

Section: Introductionmentioning

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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Comparison of absorption, luminescence and scintillation characteristics in Lu1.95Y0.05SiO5:Ce,Ca and Y2SiO5:Ce scintillators

Cited by 54 publications

References 28 publications

The role of cerium variable charge state in the luminescence and scintillation mechanism in complex oxide scintillators: The effect of air annealing

The role of cerium variable charge state in the luminescence and scintillation mechanism in complex oxide scintillators: The effect of air annealing

Effect of oxidation annealing on optical properties of YAG:Ce single crystals

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

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Comparison of absorption, luminescence and scintillation characteristics in Lu1.95Y0.05SiO5:Ce,Ca and Y2SiO5:Ce scintillators

Cited by 54 publications

References 28 publications

The role of cerium variable charge state in the luminescence and scintillation mechanism in complex oxide scintillators: The effect of air annealing

The role of cerium variable charge state in the luminescence and scintillation mechanism in complex oxide scintillators: The effect of air annealing

Effect of oxidation annealing on optical properties of YAG:Ce single crystals

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

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