Strontium iodide doped with europium (SrI2:Eu2+) is a new scintillator being developed for use in high-energy astrophysical detectors with excellent energy resolution. Nonproportionality is the primary limiting factor to improving its energy resolution, although the physics of nonproportionality is not yet fully understood. Only in the past few years have the underlying physical models of nonproportionality been reported. Materials science solutions for improving nonproportionality are also being investigated, with the main approach being the incorporation of deliberate addition of crystal defects using codoping. In this study, we look at an alternative method that is similar to codoping, using radiation damage to alter proportionality. By irradiating a SrI2:Eu2+ sample with a 2,255 Ci 137Cs source, we explore both the crystalâs potential for space-based applications in a radiation environment and this new method of altering nonproportionality. We propose a novel method of altering the nonproportionality of scintillators, using radiation-induced F-centers in place of co-dopants. We demonstrate that radiation damage is an effective approach for defect engineering that may be used to study nonproportionality in scintillators. The advantage of this proposed approach is that one can use the same crystal to vary the concentration of defects, while codoping introduces additional variables, since it requires growing a different crystal for each codoping concentration.
| Identifer | oai:union.ndltd.org:VANDERBILT/oai:VANDERBILTETD:etd-03272017-090525 |
| Date | 06 April 2017 |
| Creators | Caudel, David Dewayne |
| Contributors | Keivan Stassun, Arnold Burger, Richard Haglund, Ashley Stowe, Kirill Bolotin |
| Publisher | VANDERBILT |
| Source Sets | Vanderbilt University Theses |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.vanderbilt.edu/available/etd-03272017-090525/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Vanderbilt University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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