1. Crystal structure, electronic structure, optical and scintillation properties of self-activated Cs4YbI6.
- Author
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Wu, Yuntao, Chakoumakos, Bryan C., Shi, Hongliang, Du, Mao-Hua, Greeley, Ian, Loyd, Matthew, Rutstrom, Daniel J., Stand, Luis, Koschan, Merry, and Melcher, Charles L.
- Subjects
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SCINTILLATORS , *SINGLE crystals , *ULTRAVIOLET radiation , *SCINTILLATION spectrometry , *DIFFERENTIAL scanning calorimetry - Abstract
A self-activated Cs 4 YbI 6 single crystal was grown by the vertical Bridgman method. Crystal structure refinements verified the phase purity and the trigonal crystal system with a space group of R 3 ̅ c. By using differential scanning calorimetry, the melting and crystallization points were determined to be 550 and 510 °C, respectively. Luminescence and scintillation properties were systematically studied. Upon ultraviolet light (360 nm) excitation, the Cs 4 YbI 6 crystal exhibits bluish-green emission centered at 450 and 480 nm due to spin-allowed and spin-forbidden transitions of Yb 2+ activators. The lifetimes of the corresponding emission bands at room temperature are tens and hundreds of nanoseconds, respectively. X-ray excited radioluminescence spectrum is dominated by the spin-forbidden transition of Yb 2+ at 480 nm. The absolute light yield is 2700 ± 200 photons/MeV with a principal scintillation decay time of 33 ns. The physical explanation for the low light yield observed is proposed from experimental and theoretical insights. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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