Divalent europium doped and un-doped calcium iodide scintillators: Scintillator characterization and single crystal growth
Abstract
Initially, the alkaline-earth scintillator, CaI2:Eu2+, was discovered around 1964 by Hofstadter, Odell, and Schmidt. Serious practical problems quickly arose, however, that were associated with the growth of large monolithic single crystals of this material due to its lamellar, mica-like structure. As a result of its theoretically higher light yield, CaI2:Eu2+ has the potential to exceed the excellent scintillation performance of SrI2:Eu2+. In fact, theoretical predictions for the light yield of CaI2:Eu2+ scintillators suggested that an energy resolution approaching 2% at 662 keV could be achievable. Like the early SrI2:Eu2+ scintillator, the performance of CaI2:Eu2+ scintillators has traditionally suffered due, at least in part, to outdated materials synthesis, component stoichiometry/purity, and single-crystal-growth techniques. Based on our recent work on SrI2:Eu2+ scintillators in single-crystal form, we have developed new techniques that are applied here to CaI2:Eu2+ and pure CaI2 with the goal of growing large un-cracked crystals and, potentially, realizing the theoretically predicted performance of the CaI2:Eu2+ form of this material. Calcium iodide does not adhere to modern glassy carbon Bridgman crucibles - so there should be no differential thermal-contraction-induced crystal/crucible stresses on cooling that would result in crystal cracking of the lamellar structure of CaI2. Here we apply glassy carbon cruciblemore »
- Authors:
-
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Publication Date:
- Research Org.:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Org.:
- USDOE National Nuclear Security Administration (NNSA)
- OSTI Identifier:
- 1185906
- Alternate Identifier(s):
- OSTI ID: 1247392
- Grant/Contract Number:
- AC05-00OR22725
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment
- Additional Journal Information:
- Journal Volume: 786; Journal Issue: C; Journal ID: ISSN 0168-9002
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; Scintillator; crystal growth; Bridgman growth; CaI2:Eu; Plastic deformation
Citation Formats
Boatner, L. A., Ramey, J. O., Kolopus, J. A., and Neal, John S. Divalent europium doped and un-doped calcium iodide scintillators: Scintillator characterization and single crystal growth. United States: N. p., 2015.
Web. doi:10.1016/j.nima.2015.02.031.
Boatner, L. A., Ramey, J. O., Kolopus, J. A., & Neal, John S. Divalent europium doped and un-doped calcium iodide scintillators: Scintillator characterization and single crystal growth. United States. https://doi.org/10.1016/j.nima.2015.02.031
Boatner, L. A., Ramey, J. O., Kolopus, J. A., and Neal, John S. Sat .
"Divalent europium doped and un-doped calcium iodide scintillators: Scintillator characterization and single crystal growth". United States. https://doi.org/10.1016/j.nima.2015.02.031. https://www.osti.gov/servlets/purl/1185906.
@article{osti_1185906,
title = {Divalent europium doped and un-doped calcium iodide scintillators: Scintillator characterization and single crystal growth},
author = {Boatner, L. A. and Ramey, J. O. and Kolopus, J. A. and Neal, John S.},
abstractNote = {Initially, the alkaline-earth scintillator, CaI2:Eu2+, was discovered around 1964 by Hofstadter, Odell, and Schmidt. Serious practical problems quickly arose, however, that were associated with the growth of large monolithic single crystals of this material due to its lamellar, mica-like structure. As a result of its theoretically higher light yield, CaI2:Eu2+ has the potential to exceed the excellent scintillation performance of SrI2:Eu2+. In fact, theoretical predictions for the light yield of CaI2:Eu2+ scintillators suggested that an energy resolution approaching 2% at 662 keV could be achievable. Like the early SrI2:Eu2+ scintillator, the performance of CaI2:Eu2+ scintillators has traditionally suffered due, at least in part, to outdated materials synthesis, component stoichiometry/purity, and single-crystal-growth techniques. Based on our recent work on SrI2:Eu2+ scintillators in single-crystal form, we have developed new techniques that are applied here to CaI2:Eu2+ and pure CaI2 with the goal of growing large un-cracked crystals and, potentially, realizing the theoretically predicted performance of the CaI2:Eu2+ form of this material. Calcium iodide does not adhere to modern glassy carbon Bridgman crucibles - so there should be no differential thermal-contraction-induced crystal/crucible stresses on cooling that would result in crystal cracking of the lamellar structure of CaI2. Here we apply glassy carbon crucible Bridgman growth, high-purity growth-charge compounds, our molten salt processing/filtration technique, and extended vacuum-melt-pumping methods to the growth of both CaI2:Eu2+ and un-doped CaI2. Moreover, large scintillating single crystals were obtained, and detailed characterization studies of the scintillation properties of CaI2:Eu2+ and pure CaI2 single crystals are presented that include studies of the effects of plastic deformation of the crystals on the scintillator performance.},
doi = {10.1016/j.nima.2015.02.031},
journal = {Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment},
number = C,
volume = 786,
place = {United States},
year = {Sat Feb 21 00:00:00 EST 2015},
month = {Sat Feb 21 00:00:00 EST 2015}
}
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Works referencing / citing this record:
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