Luminescent and scintillation properties of Ce3+ doped Ca2RMgScSi3O12 (R = Y, Lu) single crystalline films

The work is dedicated to the growth and investigation of the luminescent and scintillation properties of single crystalline films (SCFs) of Ca2-xR1+xMg1+xSc1-xSi3O12:Ce (R = Y, Lu) mixed garnets with x = 0-0.25, grown using the liquid phase epitaxy method onto Y3Al5O12 substrates from PbO-B2O3 based flux. The absorption, luminescent and scintillation properties of Ca2-xY1+xMg1+xSc1-xSi3O12:Ce and Ca2-xLu1+xMg1+xSc1-xSi3O12:Ce SCFs with x = 0 and 0.25 were investigated and compared with the reference YAG:Ce and LuAG:Ce SCFs. Using the Ca2+, Mg2+ and Si4+ alloying, the Ce3+ emission spectra in Ca2-xR1+xMg1+xSc1-xSi3O12:Ce (R = Y, Lu; x = 0-0.25) SCFs can be notably extended in the red range in comparison with YAG: Ce and LuAG: Ce SCFs due to the increase of crystal field strength and Ce3+ multicenter creation in the dodecahedral positions of the lattices of these mixed garnet compounds. Due to the formation of Ce4+ ions, the as-grown Ca2-xR1+xMg1+xSc1-xSi3O12:Ce (R = Y, Lu) SCFs at x = 0 and 0.25 show relatively low light yield. However, after annealing in reducing atmosphere (95% N-2 + 5% H-2) at T > 1000 degrees C, a recharging Ce4+ -> Ce3+ takes place. After that, these SCFs possess the light yield about of 30% and 31% in comparison with the reference YAG: Ce and LuAG: Ce SCFs, respectively, and a fast scintillation response with the decay times in the ns range under a-particles excitation by Pu-239 (5.15 MeV) source

Effect of Manganese Concentration on Thermoluminescent Properties of YAlO3:MnYAlO_{3}:Mn Crystals

This work is devoted to experimental study of the effect of manganese concentration on thermoluminescent properties of $YAlO_{3}:Mn$ crystals grown by the Czochralski method. A new type of emitting centers beside of $Mn^{4+}$ and $Mn^{2+}$ ions was revealed at low concentration of manganese ions in the crystal. These centers are responsible for the high-temperature thermoluminescent peak at 570 K. A potential of this thermoluminescent peak for thermoluminescence dosimetry application is discussed

Effect of Manganese Concentration on Thermoluminescent Properties of YAlO 3

This work is devoted to experimental study of the effect of manganese concentration on thermoluminescent properties of $YAlO_{3}:Mn$ crystals grown by the Czochralski method. A new type of emitting centers beside of $Mn^{4+}$ and $Mn^{2+}$ ions was revealed at low concentration of manganese ions in the crystal. These centers are responsible for the high-temperature thermoluminescent peak at 570 K. A potential of this thermoluminescent peak for thermoluminescence dosimetry application is discussed

In situ Investigation of OH -

The work presents experimental results of an in situ investigation of the $OH^{-}$ absorption in pure and MgO-doped $LiNbO_{3}$ crystals during reducing (95% Ar + 5% $H_{2}$) and oxidizing $(O_{2})$ high-temperature treatments in the temperature range from room temperature to 820 K. The absorption spectra measured in situ at high temperatures in reducing/oxidizing atmospheres have been analyzed. The origin of the changes in optical absorption caused by heating of the crystal is discussed in terms of the OH-bonds orientation change

In situ Investigation of OH−OH^{-} Absorption in LiNbO3LiNbO_{3} and LiNbO3:MgOLiNbO_{3}:MgO Crystals during Reducing/Oxidizing Annealing

The work presents experimental results of an in situ investigation of the $OH^{-}$ absorption in pure and MgO-doped $LiNbO_{3}$ crystals during reducing (95% Ar + 5% $H_{2}$) and oxidizing $(O_{2})$ high-temperature treatments in the temperature range from room temperature to 820 K. The absorption spectra measured in situ at high temperatures in reducing/oxidizing atmospheres have been analyzed. The origin of the changes in optical absorption caused by heating of the crystal is discussed in terms of the OH-bonds orientation change

Displacement defect formation in complex oxide crystals under irradiation

The work is devoted to an analysis of formation processes of the radiation displacement defects (RDDs) and colour centres (CCs) in complex oxide crystals under irradiation. The calculation results on: the displacement process simulation as well as an analysis of the RDD and CC accumulation kinetics are presented. New experimental results on additional absorption spectra induced by neutron irradiation of LiNbO(3) (LNO) crystals doped with Fe and Cr and YAlO(3) (YAP) crystals doped with Nd and Er as well are presented. Dose dependencies of the additional absorption are compared and their peculiarities are discussed. The obtained results confirm that CCs causing the irradiation induced absorption in LNO and YAP crystals are formed in secondary processes which area affected by impurities. It is also found that the induced absorption dose dependence in LNO crystals has an unexpected slope