scholarly journals Study of defects and radiation damage in solids by field-ion and atom-probe microscopy

1979 ◽  
Author(s):  
D.N. Seidman
Keyword(s):  
Radiation Damage ◽  
Atom Probe ◽  
Probe Microscopy

scholarly journals Nanogeochronology of discordant zircon measured by atom probe microscopy of Pb-enriched dislocation loops

2016 ◽  
Vol 2 (9) ◽  
pp. e1601318 ◽  
Author(s):  
Emily M. Peterman ◽  
Steven M. Reddy ◽  
David W. Saxey ◽  
David R. Snoeyenbos ◽  
William D. A. Rickard ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Radiation Damage ◽  
Age Determination ◽  
Atom Probe ◽  
Dislocation Loops ◽  
Specific Mechanism ◽  
Heterogeneous Distribution ◽  
Probe Microscopy ◽  
Geological Evolution ◽  
Spot Analysis

Isotopic discordance is a common feature in zircon that can lead to an erroneous age determination, and it is attributed to the mobilization and escape of radiogenic Pb during its post-crystallization geological evolution. The degree of isotopic discordance measured at analytical scales of ~10 μm often differs among adjacent analysis locations, indicating heterogeneous distributions of Pb at shorter length scales. We use atom probe microscopy to establish the nature of these sites and the mechanisms by which they form. We show that the nanoscale distribution of Pb in a ~2.1 billion year old discordant zircon that was metamorphosed c. 150 million years ago is defined by two distinct Pb reservoirs. Despite overall Pb loss during peak metamorphic conditions, the atom probe data indicate that a component of radiogenic Pb was trapped in 10-nm dislocation loops that formed during the annealing of radiation damage associated with the metamorphic event. A second Pb component, found outside the dislocation loops, represents homogeneous accumulation of radiogenic Pb in the zircon matrix after metamorphism. The207Pb/206Pb ratios measured from eight dislocation loops are equivalent within uncertainty and yield an age consistent with the original crystallization age of the zircon, as determined by laser ablation spot analysis. Our results provide a specific mechanism for the trapping and retention of radiogenic Pb during metamorphism and confirm that isotopic discordance in this zircon is characterized by discrete nanoscale reservoirs of Pb that record different isotopic compositions and yield age data consistent with distinct geological events. These data may provide a framework for interpreting discordance in zircon as the heterogeneous distribution of discrete radiogenic Pb populations, each yielding geologically meaningful ages.

EXTRACTING GEOLOGIC AGES FROM ISOTOPICALLY-DISTINCT NANOSCALE RESERVOIRS OF PB IN DISCORDANT ZIRCON BY ATOM PROBE MICROSCOPY

2016 ◽  
Author(s):  
Emily M. Peterman ◽  
◽  
Steven Reddy ◽  
David W. Saxey ◽  
David R. Snoeyenbos ◽  
...  
Keyword(s):  
Atom Probe ◽  
Probe Microscopy

scholarly journals Analysis of Radiation Damage in Light Water Reactors: Comparison of Cluster Analysis Methods for the Analysis of Atom Probe Data

2017 ◽  
Vol 23 (2) ◽  
pp. 366-375 ◽  
Author(s):  
Jonathan M. Hyde ◽  
Gérald DaCosta ◽  
Constantinos Hatzoglou ◽  
Hannah Weekes ◽  
Bertrand Radiguet ◽  
...  
Keyword(s):  
Cluster Analysis ◽  
Radiation Damage ◽  
Defect Formation ◽  
Chemical Species ◽  
Atom Probe ◽  
Three Dimensions ◽  
Multiple Sources ◽  
Damage Models ◽  
Combining Data ◽  
Water Reactors

AbstractIrradiation of reactor pressure vessel (RPV) steels causes the formation of nanoscale microstructural features (termed radiation damage), which affect the mechanical properties of the vessel. A key tool for characterizing these nanoscale features is atom probe tomography (APT), due to its high spatial resolution and the ability to identify different chemical species in three dimensions. Microstructural observations using APT can underpin development of a mechanistic understanding of defect formation. However, with atom probe analyses there are currently multiple methods for analyzing the data. This can result in inconsistencies between results obtained from different researchers and unnecessary scatter when combining data from multiple sources. This makes interpretation of results more complex and calibration of radiation damage models challenging. In this work simulations of a range of different microstructures are used to directly compare different cluster analysis algorithms and identify their strengths and weaknesses.

scholarly journals TEM and Atom Probe Microscopy in the Development of Magnetic Multilayer Nano-Structures

2003 ◽  
Vol 9 (S02) ◽  
pp. 572-573
Author(s):  
P. M. Rice ◽  
T. Lin ◽  
R. E. Fontana ◽  
E. A. Delenia
Keyword(s):  
Atom Probe ◽  
Magnetic Multilayer ◽  
Probe Microscopy ◽  
Nano Structures

Nanoscale Pb clustering and multi-domain Pb-mobility in zircon

2020 ◽  
Author(s):  
Tyler Blum ◽  
Chloe Bonamici ◽  
John Valley
Keyword(s):  
Radiation Damage ◽  
Diffusion Processes ◽  
Cluster Formation ◽  
Atom Probe ◽  
Temporal Information ◽  
Multi Scale ◽  
Zircon Crystallization ◽  
Differential Retention ◽  
History Of ◽  
Nanoscale Clusters

<p>Uranium-Lead dating of zircon remains one of the most widely utilized and most reliable temporal records throughout Earth history. This stems from the mineral’s widespread occurrence, pristine zircon being both physically and chemically robust, and the ability to evaluate the presence of open system behavior (i.e. “concordance”) through comparison of the independent <sup>238</sup>U→<sup>206</sup>Pb, <sup>235</sup>U→<sup>207</sup>Pb, and <sup>232</sup>Th→<sup>208</sup>Pb decay chains. The phenomenon of discordance is well documented in zircon, and is typically (though not always) associated with radiation damage accumulation and Pb-loss. Despite a long history of research, the nanoscale controls on Pb mobility and Pb loss (i.e. the relative rates of radiation damage, annealing, and Pb diffusion) remain poorly defined. The unique characterization capabilities of atom probe tomography (APT) provide a novel means to study U-Pb systematics on the scale of the radiation damage, annealing and diffusion processes. APT studies have documented nanoscale heterogeneity in trace elements, Pb, and Pb isotope ratios, and correlated the <sup>207</sup>Pb/<sup>206</sup>Pb ratios within clusters to transient thermal episodes in the history of a zircon.</p><p> </p><p>This work seeks to provide a foundation for multi-scale U-Pb characterization, including how differential Pb mobility at the nanoscale can influence micron- to- grain-scale U-Pb systematics. Historically, concordia diagrams have used simple Pb-loss models to extract temporal information about the timing of Pb mobility/loss; however, these models assume <sup>207</sup>Pb and <sup>206</sup>Pb are uniformly disturbed within a grain and lost in equal proportions at the time of Pb loss. Our previous studies suggest that radiogenic Pb can be concentrated and immobilized in nanoscale clusters, leading to differential retention of Pb in clusters vs. matrix domains, and requiring a more complex treatment of isotopic shifts during any post-clustering Pb loss. This “multi-domain element (Pb) mobility” (MDEM or MDPM) influences subsequent Pb-loss trajectories on concordia diagrams, manifesting in systematic offsets for discordia as a function of the zircon crystallization age, the timing of cluster formation, and the timing of Pb mobility. These results highlight that (1) traditional interpretations of discordia in the presence of cryptic nanoscale clustering can lead to inaccuracies, and (2) multi-scale U-Pb characterization offers a means to both study discordance and to extract additional temporal information from zircon with otherwise ambiguous and/or complex Pb-loss patterns.</p>

A model accounting for spatial overlaps in 3D atom-probe microscopy

2001 ◽  
Vol 89 (1-3) ◽  
pp. 145-153 ◽  
Author(s):  
D. Blavette ◽  
F. Vurpillot ◽  
P. Pareige ◽  
A. Menand
Keyword(s):  
Atom Probe ◽  
Probe Microscopy

scholarly journals Exploitation of thermal gradients for investigation of irradiation temperature effects with charged particles

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Chris D. Hardie ◽  
Andrew J. London ◽  
Joven J. H. Lim ◽  
Rob Bamber ◽  
Tonči Tadić ◽  
...  
Keyword(s):  
Radiation Damage ◽  
Atom Probe ◽  
New Technique ◽  
Linear Temperature ◽  
Linear Temperature Gradient ◽  
Transmission Electron ◽  
Property Data ◽  
Wide Range ◽  
A New Technique ◽  
Effects Of Radiation

Abstract The effects of radiation damage on materials are strongly dependant on temperature, making it arguably the most significant parameter of concern in nuclear engineering. Owing to the challenges and expense of irradiating and testing materials, material property data is often limited to few irradiation conditions and material variants. A new technique has been developed which enables the investigation of radiation damage of samples subject to a thermal gradient, whereby a wealth of data over a range of irradiation temperatures is produced from a single irradiation experiment. The results produced are practically inaccessible by use of multiple conventional isothermal irradiations. We present a precipitation-hardened copper alloy (CuCrZr) case-study irradiated with a linear temperature gradient between 125 and 440 °C. Subsequent micro-scale post irradiation characterisation (nanoindentation, transmission electron microscopy and atom probe tomography) highlight the capability to observe mechanical and microstructural changes over a wide range of irradiation temperatures. We observed irradiation-softening in CuCrZr that did not occur due to irradiation-enhanced aging of the Cr-precipitates. Excellent reproducibility of the new technique was demonstrated and replicated irradiation-hardening data from several isothermal neutron irradiation studies. Our new technique provides this data at a fraction of the time and cost required by conventional irradiation experiments.

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