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Gonderman S, Tripathi J, Novakowski T, Sizyuk T, Hassanein A. Effect of dual ion beam irradiation (helium and deuterium) on tungsten–tantalum alloys under fusion relevant conditions. Nuclear Materials and Energy 2017. [DOI: 10.1016/j.nme.2017.02.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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El-Atwani O, Norris SA, Ludwig K, Gonderman S, Allain JP. Ion beam nanopatterning of III-V semiconductors: consistency of experimental and simulation trends within a chemistry-driven theory. Sci Rep 2015; 5:18207. [PMID: 26670948 PMCID: PMC4680892 DOI: 10.1038/srep18207] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 10/15/2015] [Indexed: 11/09/2022] Open
Abstract
Several proposed mechanisms and theoretical models exist concerning nanostructure evolution on III-V semiconductors (particularly GaSb) via ion beam irradiation. However, making quantitative contact between experiment on the one hand and model-parameter dependent predictions from different theories on the other is usually difficult. In this study, we take a different approach and provide an experimental investigation with a range of targets (GaSb, GaAs, GaP) and ion species (Ne, Ar, Kr, Xe) to determine new parametric trends regarding nanostructure evolution. Concurrently, atomistic simulations using binary collision approximation over the same ion/target combinations were performed to determine parametric trends on several quantities related to existing model. A comparison of experimental and numerical trends reveals that the two are broadly consistent under the assumption that instabilities are driven by chemical instability based on phase separation. Furthermore, the atomistic simulations and a survey of material thermodynamic properties suggest that a plausible microscopic mechanism for this process is an ion-enhanced mobility associated with energy deposition by collision cascades.
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Affiliation(s)
- O El-Atwani
- School of Nuclear Engineering, Purdue University, West Lafayette, IN 47907.,School of Materials Engineering, Purdue University, West Lafayette, IN 47907.,Birck Nanotechnology Center, West Lafayette, IN 47907
| | - S A Norris
- Department of Mathematics, Southern Methodist University, Dallas, TX 75275
| | - K Ludwig
- Physics Department and Division of Materials Science and Engineering, Boston University, Boston, Massachusetts, 02215, USA
| | - S Gonderman
- School of Nuclear Engineering, Purdue University, West Lafayette, IN 47907
| | - J P Allain
- School of Nuclear Engineering, Purdue University, West Lafayette, IN 47907.,Department of Nuclear, Plasma and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801
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El-Atwani O, Gonderman S, Suslov S, Efe M, De Temmerman G, Morgan T, Bystrov K, Hattar K, Allain J. Early stage damage of ultrafine-grained tungsten materials exposed to low energy helium ion irradiation. Fusion Engineering and Design 2015. [DOI: 10.1016/j.fusengdes.2015.02.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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El-Atwani O, Hinks JA, Greaves G, Gonderman S, Qiu T, Efe M, Allain JP. In-situ TEM observation of the response of ultrafine- and nanocrystalline-grained tungsten to extreme irradiation environments. Sci Rep 2014; 4:4716. [PMID: 24796578 PMCID: PMC4010930 DOI: 10.1038/srep04716] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 03/12/2014] [Indexed: 11/08/2022] Open
Abstract
The accumulation of defects, and in particular He bubbles, can have significant implications for the performance of materials exposed to the plasma in magnetic-confinement nuclear fusion reactors. Some of the most promising candidates for deployment into such environments are nanocrystalline materials as the engineering of grain boundary density offers the possibility of tailoring their radiation resistance properties. In order to investigate the microstructural evolution of ultrafine- and nanocrystalline-grained tungsten under conditions similar to those in a reactor, a transmission electron microscopy study with in situ 2 keV He(+) ion irradiation at 950 °C has been completed. A dynamic and complex evolution in the microstructure was observed including the formation of defect clusters, dislocations and bubbles. Nanocrystalline grains with dimensions less than around 60 nm demonstrated lower bubble density and greater bubble size than larger nanocrystalline (60-100 nm) and ultrafine (100-500 nm) grains. In grains over 100 nm, uniform distributions of bubbles and defects were formed. At higher fluences, large faceted bubbles were observed on the grain boundaries, especially on those of nanocrystalline grains, indicating the important role grain boundaries can play in trapping He and thus in giving rise to the enhanced radiation tolerance of nanocrystalline materials.
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Affiliation(s)
- O. El-Atwani
- School of Nuclear Engineering, Purdue University, West Lafayette, IN 47906
- School of Materials Engineering, Purdue University, West Lafayette, IN 47906
- Birck Nanotechnology Center, West Lafayette, IN 47906
| | - J. A. Hinks
- School of Computing and Engineering, University of Huddersfield, HD1 3DH, United Kingdom
| | - G. Greaves
- School of Computing and Engineering, University of Huddersfield, HD1 3DH, United Kingdom
| | - S. Gonderman
- School of Nuclear Engineering, Purdue University, West Lafayette, IN 47906
| | - T. Qiu
- School of Materials Engineering, Purdue University, West Lafayette, IN 47906
| | - M. Efe
- Center for Materials Processing and Tribology, Purdue University, West Lafayette, IN, USA
- Current address: Department of Metallurgical and Materials Engineering, Middle East Technical University, Ankara, Turkey
| | - J. P. Allain
- School of Nuclear Engineering, Purdue University, West Lafayette, IN 47906
- School of Materials Engineering, Purdue University, West Lafayette, IN 47906
- Birck Nanotechnology Center, West Lafayette, IN 47906
- Current address: Department of Nuclear, Plasma and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801
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Taylor CN, Heim B, Gonderman S, Allain JP, Yang Z, Kaita R, Roquemore AL, Skinner CH, Ellis RA. Materials analysis and particle probe: a compact diagnostic system for in situ analysis of plasma-facing components (invited). Rev Sci Instrum 2012; 83:10D703. [PMID: 23126877 DOI: 10.1063/1.4729262] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The objective of the materials analysis particle probe (MAPP) in NSTX is to enable prompt and direct analysis of plasma-facing components exposed to plasma discharges. MAPP allows multiple samples to be introduced to the level of the plasma-facing surface without breaking vacuum and analyzed using X-ray photoelectron spectroscopy (XPS), ion-scattering and direct recoil spectroscopy, and thermal desorption spectroscopy (TDS) immediately following the plasma discharge. MAPP is designed to operate as a diagnostic within the ∼12 min NSTX minimum between-shot time window to reveal fundamental plasma-surface interactions. Initial calibration demonstrates MAPP's XPS and TDS capabilities.
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Affiliation(s)
- C N Taylor
- School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907, USA
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