| NSF Org: |
DMR Division Of Materials Research |
| Recipient: |
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| Initial Amendment Date: | April 11, 2018 |
| Latest Amendment Date: | April 11, 2018 |
| Award Number: | 1806279 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Robert Meulenberg
rmeulenb@nsf.gov (703)292-2499 DMR Division Of Materials Research MPS Directorate for Mathematical and Physical Sciences |
| Start Date: | June 1, 2018 |
| End Date: | May 31, 2022 (Estimated) |
| Total Intended Award Amount: | $499,773.00 |
| Total Awarded Amount to Date: | $499,773.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
1600 HAMPTON ST COLUMBIA SC US 29208-3403 (803)777-7093 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
1600 Hampton Street Columbia SC US 29208-0001 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | SOLID STATE & MATERIALS CHEMIS |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.049 |
ABSTRACT
Non-Technical
Border protection agencies, such as Homeland Security, must be able to detect rogue radiation sources, for example dirty bombs, before they are transported into the country. A pressing need exists for large quantities of materials know as scintillators, which are used in portable detection devices. Scintillators are materials that emit visible light when exposed to radiation, and the better the scintillator, the brighter the light and the smaller the amount of radioactive material that can be detected. This research, funded by the Solid State and Materials Chemistry Program in the Division of Materials Research at NSF, involves the fundamental aspects of crystal growth of improved scintillating materials and thereby advances the field of radiation detection. In addition, this research project provides a valuable educational experience for graduate and undergraduate students. Conducting this research trains students in the art of crystal growth and teaches them the concept of experimental design and methods optimization. Overall, this research contributes to the education and training of a wide range of individuals, including those from underrepresented groups, in the area of solid state and materials chemistry.
Technical
One area where the development of new functional materials can have a tremendous impact is homeland security. There exists a pressing need for large quantities of efficient scintillating materials for improved radiation detection. This research focuses on the synthesis of new neutron, X-ray, and gamma-ray activated scintillating oxides. Fluorine in mixed anion phases has been identified as one element that plays a crucial role in the intensity of fluorescence, and it has been demonstrated that fluorine can also increase the scintillation efficiency of rare earth silicates. Specifically, it is known that luminescent oxyfluorides in which the fluorine anions are located in LnOxFy polyhedra, such as in Cs3LnSi4O10F2 (Ln = Eu, Tb), a recently discovered brightly scintillating material, can exhibit scintillation as bright as Lu2SiO5:Ce3+. The targeted crystal growth of fluorine containing mixed-anion phases takes advantage of a recently developed enhanced flux growth technique that is known to yield crystals of oxyfluorides and salt-inclusion silicates. To better understand the processes involved in the formation of mixed anion phases in the various flux environments that are used for synthesis of complex oxide single crystals, in-situ neutron diffraction experiments are carried out to identify the optimal growth conditions for preparing new scintillators in the laboratory as well as to transform crystal growth from an empirical to a deliberate process. Additionally, this research contributes to the education and training of a wide range of individuals, including those from underrepresented groups, in the area of solid state and materials chemistry, for example through collaboration with Claflin University, an HBCU institution.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
The discovery of optically active materials and the ability to grow them as single crystals is at the core of modern materials research and encompasses a broad range of both theoretical and experimental activities. One area in which optically active materials promise to play an integral role is homeland security, where there exists a pressing need for large quantities of efficient and inexpensive scintillator materials for improved radiation detection. Scintillators, materials that can both absorb high energy radiation and convert this energy into excited states in active luminescence centers for light emission, have many uses ranging from X-ray photography, to X-ray phosphors, to PET and CT scanners, X-ray and neutron detectors, and, more recently, by homeland security for improved nuclear detection systems. The discovery of these materials will help make America a safer place. Meeting this need constitutes an important aspect of new materials development, where one ongoing challenge is the targeted discovery of new (or modified) strongly scintillating materials. Numerous approaches were taken including 1) the preparation of single crystals of novel chemical compositions with specific structural motifs known to favor scintillation and 2) the modification of existing materials to enhance the desired scintillating properties via our extensive understanding of crystal chemistry, i.e., structure-composition-property relationships, as well as fine tuning of dopant concentration. This research created almost 50 new materials, many of which luminesced and scintillated. We expect that the impact of this research will reach far beyond scintillation materials and potentially transform how we will approach crystal growth and new material discovery in the future.
The synthesis and characterization of new materials that resulted from this research is one important component of, and one driving force behind, solid-state chemistry research. The use high temperature solutions and mild hydrothermal methods to grow crystals of the desired scintillating materials have resulted in new materials that can advance the field of radiation detection, while at the same time it provided a valuable educational experience for graduate and undergraduate students. Several graduate students were trained in the science of crystal growth and educated in experimental design and methods optimization. Most importantly, their involvement in this research project taught them fundamental concepts concerning oxide materials and crystal growth, crystal structure determination, and general physical property measurements, including luminescence and scintillation. This research has contributed to the education of a wide range of individuals, including those from underrepresented groups.
Last Modified: 06/02/2022
Modified by: Hans-Conrad Zur Loye
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