Determination of thermal expansion of KCaI3 using in-situ high temperature powder X-ray diffraction

Adam C. Lindsey, Matthew Loyd, Maulik K. Patel, Ryan Rawl, Haidong Zhou, Merry Koschan, Charles L. Melcher, Mariya Zhuravleva

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

KCaI3: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 KCaI3 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 KCaI3 samples has the highest degree of anisotropy with respect to the b and c axis with ratio ᾱb/ᾱc of 1.4–1.5. Additionally, we identify the predominant cleavage plane in KCaI3 as (0 -3 -1) based upon Laue reflection imaging.

Original languageEnglish
Pages (from-to)161-166
Number of pages6
JournalMaterials Chemistry and Physics
Volume212
DOIs
StatePublished - Jun 15 2018
Externally publishedYes

Funding

This work has been supported by the U.S. Department of Homeland Security , Domestic Nuclear Detection Office , under competitively awarded grant # 2012-DN-077-ARI067-05 . This support does not constitute an express or implied endorsement on the part of the Government. Dr. Haidong Zhou thanks the support from award #NSF-DMR-1350002. The X-ray diffraction experiments were performed using the instruments procured through the general infrastructure grant of DOE-Nuclear Energy University Program #DE-NE0000693.

FundersFunder number
U.S. Department of Homeland Security
Domestic Nuclear Detection OfficeDMR-1350002, 2012-DN-077-ARI067-05

    Keywords

    • Bridgman technique
    • Halides
    • Scintillator materials
    • X-ray diffraction

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