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Growth and Optical Characterization of Europium and Cerium Doped KCl Single Crystals by Czochralski Method for Dosimetric Applications
摘要： Rare-earth-doped alkali halide single crystals KCl:Eu, KCl:Ce, and KCl:Eu,Ce were grown from melt using the Czochralski technique, and optical characterization was carried out with the prime focus on dosimetric applications. The grown crystals were investigated using XRD analysis, PL analysis, TSL measurements, and OSL measurements. The XRD of the crystals matched well with ICDD patterns (00-041-1476), and diffraction peaks can be assigned to the KCl structure, indicating that all the crystals have the same structure as KCl. The enhanced intensity of TSL and OSL was observed for co-doping of (Eu, Ce) in KCl crystals as compared to single doping. The appearance of a single glow peak in KCl:Eu,Ce at 230°C compared to single-doped KCl:Ce crystals suggested the use of the material in TL dosimetry. The intensity of OSL also showed a two-fold increase compared to single-doped crystals, suggesting its use in OSL dosimetry. PL studies showed a very high enhancement of intensity in Eu2+ emissions, reaching a maximum of about 421 nm in the (Eu2+, Ce3+) co-doped crystal compared to single-doped crystals. This justifies the occurrence of energy transfer from Ce3+ to Eu2+ in the KCl host lattice. These results showed that KCl:Eu,Ce acts as a potential TL and OSL dosimeter due to its high sensitivity to ionizing radiation.
关键词： crystal growth,Single crystal,potassium chloride,optical characterization,Czochralski method
更新于2025-09-23 15:23:52
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Evolving Crystal Morphology of Potassium Chloride Controlled by Optical Trapping
摘要： Dynamic morphology evolution of potassium chloride (KCl) crystal was demonstrated by surface optical trapping with a focused continuous-wave near-infrared laser. Optical trapping at an air/solution interface triggered the crystallization, and then the dynamic change in crystal morphology was observed in real time. We observed three different crystal morphologies of needle, rectangle, and cubic at the early stage of crystallization. As the laser power increases, the probability of generation of a cubic crystal increases, especially upon the irradiation with linear polarization. We also found laser-polarization-dependent morphology evolution by the continuous irradiation to the generated crystals. Upon linearly-polarized laser irradiation, the stepwise morphology evolutions from needle, rectangle, and eventually to cubic, which is an equilibrium shape of KCl crystal. While, circularly-polarized laser irradiation only induced morphology evolution from needle to rectangle, without morphology change into cubic, because the rectangle crystal was dissolved while crystal rotating. It was made possible to observe such a unique morphological evolution due to the spatiotemporal controllability of our crystallization method. The dynamics and mechanism of these intriguing phenomena are discussed from the perspective of a dense cluster domain formed by optical trapping before nucleation.
关键词： laser polarization,potassium chloride,crystal morphology,optical trapping,surface crystallization
更新于2025-09-19 17:13:59