1. Determination of thermal expansion of KCaI3 using in-situ high temperature powder X-ray diffraction.
- Author
-
Lindsey, Adam C., Loyd, Matthew, Patel, Maulik K., Rawl, Ryan, Zhou, Haidong, Koschan, Merry, Melcher, Charles L., and Zhuravleva, Mariya
- Subjects
- *
THERMAL expansion , *X-ray powder diffraction , *SCINTILLATION of radio waves , *LAUE experiment , *OPTICAL reflection - Abstract
KCaI 3 :Eu single crystals exhibit favorable scintillation properties and have potential for use in domestic security applications requiring radioisotope identification. The anisotropic thermal expansion of the orthorhombic unit cell of this perovskite-type scintillator has been investigated using in-situ high temperature X-ray diffraction on powdered samples. Samples from single crystals of both pure and Eu-doped KCaI 3 grown by the Bridgman method were used for comparison. Expansion with temperature along the b -axis is greatest with an average linear coefficient of thermal expansion of ≈ (41–46) x 10 −6 K −1 resulting from the weaker bonding between alternating layers of K and Ca parallel to the b -axis. Thermal expansion in each of the KCaI 3 samples has the highest degree of anisotropy with respect to the b and c axis with ratio ᾱ b /ᾱ c of 1.4–1.5. Additionally, we identify the predominant cleavage plane in KCaI 3 as (0 -3 -1) based upon Laue reflection imaging. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF