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Michael K Miller - One of the best experts on this subject based on the ideXlab platform.

  • Atom-Probe Tomography: The Local Electrode Atom Probe
    2014
    Co-Authors: Michael K Miller
    Abstract:

    Introduction to Atom Probe Tomography.- Introduction to the Physics of Field Ion Emitters.- Field Evaporation and Related Topics.- The Art of Specimen Preparation.- The Local Electrode Atom Probe.- Data Reconstruction.- Data Analysis.- Appendices.

  • The future of Atom Probe tomography
    Materials Today, 2012
    Co-Authors: Michael K Miller, Thomas F. Kelly, Krishna Rajan, Simon P Ringer
    Abstract:

    The dream of the microscopy and materials science communities is to see, identify, accurately locate, and determine the fundamental physical properties of every Atom in a specimen. With this knowledge together with modern computer models and simulations, a full understanding of the properties of a material can be determined. This fundamental knowledge leads to the design and development of more advanced materials for solving the needs of society. The technique of Atom Probe tomography is the closest to fulfilling this dream but is still significantly short of the goal. The future of Atom Probe tomography, and the prospects for achieving this ultimate goal are outlined.

  • Introduction: Special Issue on Atom Probe Tomography
    Microscopy and Microanalysis, 2007
    Co-Authors: Simon P Ringer, Michael K Miller, David J. Larson, Michael P Moody, Thomas F. Kelly
    Abstract:

    In February 2006, in conjunction with the 19th Australian Conference on Microscopy and Microanalysis held in Sydney, the 2nd Australian Workshop on Atom Probe Tomography was convened by S.P. Ringer, M.K. Miller, D.A. Saxey, and R. Zheng at the Australian Key Centre for Microscopy and Microanalysis at The University of Sydney. The topics covered at that workshop included specimen preparation; data acquisition and data analysis methods for Atom Probe tomography; applications to spinodal alloys, phase transformations, light metals, Atomic clustering, and detection methods, as well as future directions of the science and technology of Atom Probe tomography. The presentations and discussions that took place at this workshop, which was attended by more than 30 people, provided the inspiration for this special issue of Microscopy and Microanalysis .

  • Embrittlement of RPV steels: An Atom Probe tomography perspective
    Journal of Nuclear Materials, 2007
    Co-Authors: Michael K Miller, Kaye F Russell
    Abstract:

    Atom Probe tomography has played a key role in the understanding of the embrittlement of neutron irradiated reactor pressure vessel steels through the Atomic level characterization of the microstructure. Atom Probe tomography has been used to demonstrate the importance of the post weld stress relief treatment in reducing the matrix copper content in high copper alloys, the formation of ∼2-nm-diameter copper-, nickel-, manganese- and silicon-enriched precipitates during neutron irradiation in copper containing RPV steels, and the coarsening of these precipitates during post irradiation heat treatments. Atom Probe tomography has been used to detect ∼2-nm-diameter nickel-, silicon- and manganese-enriched clusters in neutron irradiated low copper and copper free alloys. Atom Probe tomography has also been used to quantify solute segregation to, and precipitation on, dislocations and grain boundaries.

  • First local electrode Atom Probe analysis of magnetite (Fe3O4)
    2004
    Co-Authors: K. R. Kuhlman, T. F. Kelly, Michael K Miller
    Abstract:

    We have successfully fabricated Atom Probe samples of a metamorphic magnetite and performed an analysis of one of these samples using a local electrode Atom Probe (LEAP).

Baptiste Gault - One of the best experts on this subject based on the ideXlab platform.

  • Reconstructing Atom Probe data: A review
    Ultramicroscopy, 2013
    Co-Authors: François Vurpillot, Baptiste Gault, Brian P. Geiser, David J. Larson
    Abstract:

    Atom Probe tomography stands out from other materials characterisation techniques mostly due to its capacity to map individual Atoms in three-dimensions with high spatial resolution. The methods used to transform raw detector data into a three-dimensional reconstruction have, comparatively to other aspects of the technique, evolved relatively little since their inception more than 15 years ago. However, due to the importance of the fidelity of the data, this topic is currently attracting a lot of interest within the Atom Probe community. In this review we cover: (1) the main aspects of the image projection, (2) the methods used to build tomographic reconstructions, (3) the intrinsic limitations of these methods, and (4) future potential directions to improve the integrity of Atom Probe tomograms.

  • Atom Probe crystallography
    Materials Today, 2012
    Co-Authors: Baptiste Gault, Michael P Moody, Julie M Cairney, Simon P Ringer
    Abstract:

    This review addresses new developments in the emerging area of “Atom Probe crystallography”, a materials characterization tool with the unique capacity to reveal both composition and crystallographic structure at the Atomic scale. This information is crucial for the manipulation of microstructure for the design of both structural and functional materials with optimized mechanical, electric, optoelectronic, magnetic, or superconducting properties that will find application in, for example, nanoelectronics or energy generation. The ability to extract crystallographic information from 3D Atomistic reconstruction has exciting potential synergies with modern modeling techniques, blending experimental and computational methods to extend our insight.

  • Atom Probe microscopy
    2012
    Co-Authors: Baptiste Gault, Michael P Moody, Julie M Cairney, Simon P Ringer
    Abstract:

    Preface Acknowledgements List of Acronyms and Abbreviations List of Terms List of Non-SI Units and Constant Values PART I Fundamentals 1. Introduction 2. Field Ion Microscopy 2.1 Principles 2.1.1 Theory of field ionisation 2.1.2 'Seeing' Atoms - field ion microscopy 2.1.3 Spatial resolution of the FIM 2.2 Instrumentation and Techniques for FIM 2.2.1 FIM instrumentation 2.2.2 eFIM or digital FIM 2.2.3 Tomographic FIM Techniques 2.3 Interpretation of FIM Images 2.3.1 Interpretation of the image in a pure material 2.3.2 Interpretation of the image for alloys 2.3.3 Selected applications of the FIM 2.3.4 Summary 3 From Field Desorption Microscopy to Atom Probe Tomography 3.1 Principles 3.1.1 Theory of field evaporation 3.1.2 'Analysing' Atoms one-by-one: Atom Probe tomography 3.2 Instrumentation and Techniques for APT 3.2.1 Experimental setup 3.2.2 Field desorption microscopy 3.2.3 High voltage pulsing techniques 3.2.4 Laser pulsing techniques 3.2.5 Energy compensation techniques Part II Practical aspects 4. Specimen Preparation 4.1 Introduction 4.1.1 Sampling issues in microscopy for materials science and engineering 4.1.2 Specimen requirements 4.2 Polishing methods 4.2.1 The electropolishing process 4.2.2 Chemical polishing 4.2.3 Safety Considerations 4.2.4 Advantages and limitations 4.3 Broad ion beam techniques 4.4 Focused ion beam techniques 4.4.1 Cut-away methods 4.4.2 Lift-out methods 4.4.3 The final stages of FIB preparation 4.4.4 Understanding and minimising ion beam damage and other artefacts 4.5 Deposition methods 4.6 Methods for organic materials 4.6.1 Polymer microtips 4.6.2 Self-assembled monolayers 4.6.3 Cryopreparation 4.7 Other Methods 4.7.1 Dipping 4.7.2 Direct growth of suitable structures 4.8 Specimen geometry issues 4.8.1 Influence of specimen geometry on Atom Probe data 4.8.2 Stress states and specimen rupture 4.9 A guide to selecting an appropriate specimen preparation method 5. Experimental protocols in Field Ion Microscopy 5.1 Step-by-step procedures for FIM 5.2 Operational space of the field ion microscope 5.2.1 Imaging gas 5.2.2 Temperature 5.2.3 The best image field 5.2.4 Other parameters 5.2.5 Summary 6. Experimental protocols 6.1 Specimen alignment 6.2 Aspects of mass spectrometry 6.2.1 Detection of the ions 6.2.2 Mass spectra 6.2.3 Formation of the mass spectrum 6.2.4 Mass resolution 6.2.5 Common artefacts 6.2.6 Elemental identification 6.2.7 Measurement of the composition 6.2.8 Detectability 6.3 Operational space 6.3.1 Flight path 6.3.2 Temperature / Pulse fraction 6.3.3 Selecting the pulsing mode 6.3.4 Pulse rate 6.3.5 Detection rate 6.4 Specimen failure 6.5 Data quality assessment 6.5.1 Field desorption map 6.5.2 Mass spectrum 6.5.3 Multiple events 6.5.4 Discussion 7. Tomographic reconstruction 7.1 Projection of the ions 7.1.1 Estimation of the electric field 7.1.2 Field distribution 7.1.3 Ion trajectories 7.1.4 Point projection 7.1.5 Radial projection with angular compression 7.1.6 Discussion 7.2 Reconstruction 7.2.1 General considerations 7.2.2 Bas et al. protocol 7.2.3 Geiser et al. protocol 7.2.4 Gault et al. protocol 7.2.5 Reflectron-fitted instruments 7.2.6 Summary and discussion 7.3 Calibration of the parameters 7.3.2 Discussion 7.3.3 Limitations of the current procedure 7.4 Common artefacts 7.4.2 Correction of the reconstruction 7.5 Perspectives on the reconstruction in Atom Probe tomography 7.5.1 Advancing the reconstruction by correlative microscopy 7.5.2 In correlation with simulations 7.5.3 Alternative ways to exploit existing data 7.6 Spatial resolution in APT 7.6.1 Introduction 7.6.2 Means of investigation 7.6.3 Definition 7.6.4 On the in-depth resolution 7.6.5 On the lateral resolution 7.6.6 Optimisation of the spatial resolution 7.7 Lattice rectification PART III Applying Atom Probe techniques for materials science 8. Analysis techniques for Atom Probe tomography 8.1 Characterising the Mass Spectrum 8.1.1 Noise Reduction 8.1.2 Quantifying Peak Contributions via Isotope Natural Abundances 8.1.3 Spatially dependent identification of mass peaks 8.1.4 Multiple Detector Event Analyses 8.2 Characterising the chemical distribution 8.2.1 Quality of Atom Probe data 8.2.2 Random comparators 8.3 Grid-based counting statistics 8.3.1 Voxelisation 8.3.2 Density 8.3.3 Concentration analyses 8.3.4 Smoothing by delocalisation 8.3.5 Visualisation techniques based on iso-concentration and iso-density 8.3.6 One-dimensional profiles 8.3.7 Grid-based frequency distribution analyses 8.4 Techniques for describing Atomic architecture 8.4.1 Nearest neighbour distributions 8.4.2 Cluster Identification Algorithms 8.4.3 Detection Efficiency Influence on Nanostructural Analyses 8.5 Radial Distribution 8.5.1 Radial distribution and pair correlation functions 8.5.2 Solute Short Range Order Parameters 8.6 Structural Analyses 8.6.1 Fourier Transforms for APT 8.6.2 Spatial Distribution Maps 8.6.3 Hough Transform 9. Atom Probe microscopy and materials science 9.1 Compositional analysis 9.2 Defects/ dislocations 9.3 Solid solutions / clustering 9.4 Precipitates 9.5 Ordering reaction 9.6 Spinodal decomposition 9.7 Interface/boundaries/layers 9.8 Amorphous materials 9.9 Atom Probe crystallography Appendices A. Appendix - chi2 distribution B. Appendix - Polishing chemicals and conditions C. File formats used in APT POS EPOS RNG RRNG ATO ENV PoSAP Cameca root files - RRAW, RHIT, ROOT D. Appendix - Image Hump Model Predictions E. Appendix - Essential Crystallography for APT Bravais lattices Notation Structure factor (F) rules for BCC, FCC, HCP Interplanar spacings (dhkl) Interplanar angles (phi) F. Stereographic Projections and commonly observed desorption maps Stereographic projection for the most commonly found structures and orientations Face-centred cubic Body-centred cubic Diamond cubic Hexagonal close-packed G. Periodic tables H. Kingham Curves I. List of elements and associated mass to charge ratios J. Possible element identity of peaks as a function of their location in the mass spectrum

  • Experimental Protocols in Atom Probe Tomography
    Atom Probe Microscopy, 2012
    Co-Authors: Baptiste Gault, Michael P Moody, Julie M Cairney, Simon P Ringer
    Abstract:

    In this chapter, each step of an Atom Probe tomography experiment is described sequentially, from the alignment of the specimen to its probable fracture, which is the most usual termination of an experiment. The influence of the main experimental parameters—base temperature, detection rate, pulsing mode, etc.—is discussed with the aim of helping the Atom Probe user to understand the mechanisms underpinning how these parameters could change the data collected, and hence to select parameters to obtain the best possible data. A set of metrics is introduced that can be used to assess the quality of the data. Of these, several can be assessed as the analysis is being performed, including the measured composition within a dataset, the signal-to-background ratio, the quality of the field desorption map, or the amount of multiple events. Of course, the quality of the tomographic reconstruction is an a posteriori criterion.

  • impact of directional walk on Atom Probe microanalysis
    Ultramicroscopy, 2012
    Co-Authors: Baptiste Gault, Khalid Hoummada, Frédéric Danoix, Dominique Mangelinck, Harald Leitner
    Abstract:

    Abstract In the Atom Probe microanalysis of steels, inconsistencies in the measured compositions of solutes (C, N) have often been reported, as well as their appearance as molecular ions. Here we propose that these issues might arise from surface migration of solute Atoms over the specimen surface. Surface migration of solutes is evidenced by field-ion microscopy observations, and its consequences on Atom Probe microanalysis are detailed for a wide range of solute (P, Si, Mn, B, C and N). It is proposed that directional walk driven by field gradients over the specimen surface and thermally activated is the prominent effect.

G.d.w. Smith - One of the best experts on this subject based on the ideXlab platform.

  • Studies of dislocations by field ion microscopy and Atom Probe tomography
    Philosophical Magazine, 2013
    Co-Authors: G.d.w. Smith, D. Hudson, P.d. Styman, Ceri A. Williams
    Abstract:

    Alan Cottrell was among the first to recognize the potential of field ion microscopy for the Atomic-scale study of crystal defects. The study of Atomic configurations at the core of dislocations by this method proved to be unexpectedly difficult, because of the mechanical stresses imposed on the specimen by the high electric field. The development of Atom Probe tomography revitalized such studies. In particular, the Atom Probe technique permitted the first direct observations of solute Atom distributions in the region of dislocations and confirmed the existence of so-called ‘Cottrell Atmospheres’ which are of great importance in the understanding of phenomena such as strain ageing. Atom Probe studies of dislocation–solute interactions in a diverse range of alloy systems are outlined.

  • Applications of Atom Probe Microanalysis in Materials Science.
    MRS Bulletin, 1994
    Co-Authors: M. K. Miller, G.d.w. Smith
    Abstract:

    The Atom Probe field ion microscope is the most powerful and direct method for the analysis of materials at the Atomic level. Since analyses are performed by collecting Atoms one at a time from a small volume, it is possible to conduct fundamental characterization of materials at this level. The Atom Probe technique is applicable to a wide range of materials since its only restriction is that the material under analysis must possess at least some limited electrical conductance. Therefore, since its introduction in 1968, the Atom Probe field ion microscope has been used in many diverse applications in most branches of materials science. Many of the applications have exploited its high spatial resolution capabilities to perform microstructural characterizations of features such as grain boundaries and other interfaces and ultrafine scale precipitation that are not possible with other microanaly tical techniques. This article briefly outlines some of the capabilities and applications of the Atom Probe. The details of the Atom Probe technique are described elsewhere. The power of the Atom Probe may be demonstrated by its ability to see and identify a single Atom, which is particularly useful in characterizing solute segregation to grain boundaries or other interfaces. An example of a brightly-imaging solute Atom at a grain boundary in a nickel aluminide is shown in Figure 1. In order to conclusively determine its identity, its image is aligned with the Probe aperture in the center of the imaging screen and then the selected Atom is carefully removed by field evaporation and analyzed in the time-of-flight mass spectrometer. This and many other bright spots in this material were shown to be boron Atoms. This example also illustrates the light element analytical capability of the Atom Probe. In fact, the Atom Probe may to used to analyze all elements in the periodic table and has had applications ranging from characterizing the distribution of implanted hydrogen to phase transformations in uranium alloys.

  • Ultra-high-resolution chemical analysis by field-ion microscopy, Atom Probe and position-sensitive Atom-Probe techniques
    Ultramicroscopy, 1992
    Co-Authors: Chris R. M. Grovenor, Alfred Cerezo, Paul J. Warren, G.d.w. Smith, Jm M. Hyde, J.a. Liddle, R.a.d. Mackenzie, R.p. Setna, J.e. Brown, I. Stark
    Abstract:

    Abstract This paper describes some recent results on the use of field-ion microscopy and Atom-Probe techniques in the study of the fine-scale chemistry of a range of different materials. It is shown that field-ion images of the early stages of precipitation in metallurgical alloys can give morphological information before any significant contrast can be achieved by conventional transmission electron microscopy (TEM), and that the composition of these nanometer-scale particles can be accurately analysed by the use of Atom-Probe microanalysis. In addition, the recent development of the position-sensitive Atom Probe (POSAP) allows a three-dimensional composition map to be obtained of the elemental distribution in and around these particles. In this way a more complete picture can be obtained of the morphology and chemistry of complex, fine-scale structures than is readily obtainable from TEM-based techniques.

  • Ultra-high resolution chemical analysis by field-ion Atom Probe/position sensitive Atom Probe techniques
    Proceedings annual meeting Electron Microscopy Society of America, 1991
    Co-Authors: Chris R. M. Grovenor, M.g. Hetherington, A. Cerezo, J.a. Liddle, R.a.d. Mackenzie, G.d.w. Smith
    Abstract:

    The use of field ion microscopy based techniques in the study of the structure and chemistry of metallic and semiconducting materials with very high resolution is now well documented. The particular features of these techniques which result in the achievement of very high spatial resolution in images and chemical profiles are; the intrinsic magnification in a conventional field ion microscope of at least 106, the plane-by-plane desorption characteristic of field evaporation processes, and the excellent chemical specificity in a modern Atom Probe. In addition, we have developed in Oxford a new detector system for field ion based equipment in which both the chemical identity of evaporated ions and the position on the sample surface from which they were evaporated can be established. This allows the reconstruction of the evaporated volume in three dimensions, and this technique has been christened the Position Sensitive Atom Probe, POSAP. This abstract presents the results of two typical experiments illustrating the very high quality of the chemical data that can be obtained in both conventional Atom Probe and POSAP facilities.

David J. Larson - One of the best experts on this subject based on the ideXlab platform.

  • Reconstructing Atom Probe data: A review
    Ultramicroscopy, 2013
    Co-Authors: François Vurpillot, Baptiste Gault, Brian P. Geiser, David J. Larson
    Abstract:

    Atom Probe tomography stands out from other materials characterisation techniques mostly due to its capacity to map individual Atoms in three-dimensions with high spatial resolution. The methods used to transform raw detector data into a three-dimensional reconstruction have, comparatively to other aspects of the technique, evolved relatively little since their inception more than 15 years ago. However, due to the importance of the fidelity of the data, this topic is currently attracting a lot of interest within the Atom Probe community. In this review we cover: (1) the main aspects of the image projection, (2) the methods used to build tomographic reconstructions, (3) the intrinsic limitations of these methods, and (4) future potential directions to improve the integrity of Atom Probe tomograms.

  • Atom Probe tomography 2012
    Annual Review of Materials Research, 2012
    Co-Authors: Thomas F. Kelly, David J. Larson
    Abstract:

    In the world of tomographic imaging, Atom Probe tomography (APT) occupies the high-spatial-resolution end of the spectrum. It is highly complementary to electron tomography and is applicable to a wide range of materials. The current state of APT is reviewed. Emphasis is placed on applications and data analysis as they apply to many fields of research and development including metals, semiconductors, ceramics, and organic materials. We also provide a brief review of the history and the instrumentation associated with APT and an assessment of the existing challenges in the field.

  • The second revolution in Atom Probe tomography
    Mrs Bulletin, 2012
    Co-Authors: Thomas F. Kelly, David J. Larson
    Abstract:

    There has been explosive growth in the performance and consequential adoption of Atom Probe tomography in the past decade, which was fueled by the development of the commercial local-electrode Atom Probe (LEAP) and technologies for specimen preparation. The LEAP introduced to Atom Probes orders-of-magnitude increases in data collection rates and field of view while improving mass resolution and greatly improving ease of use. These developments constitute the second revolution in the field since the invention of the Atom Probe in 1967 and Atom Probe tomography in 1973: the invention of the three-dimensional Atom Probe was the first revolution. This article seeks to put this second revolution into historical perspective by recounting the essential developments that led to this point. In particular, the role of Erwin Muller, the inventor of the Atom Probe and related instruments, is highlighted. From the invention of the field emission electron microscope to the field ion microscope to the Atom Probe and beyond, he created a field of microscopy that is thriving today. Next, the state of the art in Atom Probe instrumentation is illustrated with a current application. Finally, a brief look toward future developments is provided, which may include superconducting detectors and integration of Atom Probes with transmission electron microscopes.

  • review of Atom Probe fib based specimen preparation methods
    Microscopy and Microanalysis, 2007
    Co-Authors: M. K. Miller, K F Russell, K Thompson, Roger Alvis, David J. Larson
    Abstract:

    Several FIB-based methods that have been developed to fabricate needle-shaped Atom Probe specimens from a variety of specimen geometries, and site-specific regions are reviewed. These methods have enabled electronic device structures to be characterized. The Atom Probe may be used to quantify the level and range of gallium implantation and has demonstrated that the use of low accelerating voltages during the final stages of milling can dramatically reduce the extent of gallium implantation.

  • Introduction: Special Issue on Atom Probe Tomography
    Microscopy and Microanalysis, 2007
    Co-Authors: Simon P Ringer, Michael K Miller, David J. Larson, Michael P Moody, Thomas F. Kelly
    Abstract:

    In February 2006, in conjunction with the 19th Australian Conference on Microscopy and Microanalysis held in Sydney, the 2nd Australian Workshop on Atom Probe Tomography was convened by S.P. Ringer, M.K. Miller, D.A. Saxey, and R. Zheng at the Australian Key Centre for Microscopy and Microanalysis at The University of Sydney. The topics covered at that workshop included specimen preparation; data acquisition and data analysis methods for Atom Probe tomography; applications to spinodal alloys, phase transformations, light metals, Atomic clustering, and detection methods, as well as future directions of the science and technology of Atom Probe tomography. The presentations and discussions that took place at this workshop, which was attended by more than 30 people, provided the inspiration for this special issue of Microscopy and Microanalysis .

Simon P Ringer - One of the best experts on this subject based on the ideXlab platform.

  • Atom Probe crystallography
    Materials Today, 2012
    Co-Authors: Baptiste Gault, Michael P Moody, Julie M Cairney, Simon P Ringer
    Abstract:

    This review addresses new developments in the emerging area of “Atom Probe crystallography”, a materials characterization tool with the unique capacity to reveal both composition and crystallographic structure at the Atomic scale. This information is crucial for the manipulation of microstructure for the design of both structural and functional materials with optimized mechanical, electric, optoelectronic, magnetic, or superconducting properties that will find application in, for example, nanoelectronics or energy generation. The ability to extract crystallographic information from 3D Atomistic reconstruction has exciting potential synergies with modern modeling techniques, blending experimental and computational methods to extend our insight.

  • Atom Probe microscopy
    2012
    Co-Authors: Baptiste Gault, Michael P Moody, Julie M Cairney, Simon P Ringer
    Abstract:

    Preface Acknowledgements List of Acronyms and Abbreviations List of Terms List of Non-SI Units and Constant Values PART I Fundamentals 1. Introduction 2. Field Ion Microscopy 2.1 Principles 2.1.1 Theory of field ionisation 2.1.2 'Seeing' Atoms - field ion microscopy 2.1.3 Spatial resolution of the FIM 2.2 Instrumentation and Techniques for FIM 2.2.1 FIM instrumentation 2.2.2 eFIM or digital FIM 2.2.3 Tomographic FIM Techniques 2.3 Interpretation of FIM Images 2.3.1 Interpretation of the image in a pure material 2.3.2 Interpretation of the image for alloys 2.3.3 Selected applications of the FIM 2.3.4 Summary 3 From Field Desorption Microscopy to Atom Probe Tomography 3.1 Principles 3.1.1 Theory of field evaporation 3.1.2 'Analysing' Atoms one-by-one: Atom Probe tomography 3.2 Instrumentation and Techniques for APT 3.2.1 Experimental setup 3.2.2 Field desorption microscopy 3.2.3 High voltage pulsing techniques 3.2.4 Laser pulsing techniques 3.2.5 Energy compensation techniques Part II Practical aspects 4. Specimen Preparation 4.1 Introduction 4.1.1 Sampling issues in microscopy for materials science and engineering 4.1.2 Specimen requirements 4.2 Polishing methods 4.2.1 The electropolishing process 4.2.2 Chemical polishing 4.2.3 Safety Considerations 4.2.4 Advantages and limitations 4.3 Broad ion beam techniques 4.4 Focused ion beam techniques 4.4.1 Cut-away methods 4.4.2 Lift-out methods 4.4.3 The final stages of FIB preparation 4.4.4 Understanding and minimising ion beam damage and other artefacts 4.5 Deposition methods 4.6 Methods for organic materials 4.6.1 Polymer microtips 4.6.2 Self-assembled monolayers 4.6.3 Cryopreparation 4.7 Other Methods 4.7.1 Dipping 4.7.2 Direct growth of suitable structures 4.8 Specimen geometry issues 4.8.1 Influence of specimen geometry on Atom Probe data 4.8.2 Stress states and specimen rupture 4.9 A guide to selecting an appropriate specimen preparation method 5. Experimental protocols in Field Ion Microscopy 5.1 Step-by-step procedures for FIM 5.2 Operational space of the field ion microscope 5.2.1 Imaging gas 5.2.2 Temperature 5.2.3 The best image field 5.2.4 Other parameters 5.2.5 Summary 6. Experimental protocols 6.1 Specimen alignment 6.2 Aspects of mass spectrometry 6.2.1 Detection of the ions 6.2.2 Mass spectra 6.2.3 Formation of the mass spectrum 6.2.4 Mass resolution 6.2.5 Common artefacts 6.2.6 Elemental identification 6.2.7 Measurement of the composition 6.2.8 Detectability 6.3 Operational space 6.3.1 Flight path 6.3.2 Temperature / Pulse fraction 6.3.3 Selecting the pulsing mode 6.3.4 Pulse rate 6.3.5 Detection rate 6.4 Specimen failure 6.5 Data quality assessment 6.5.1 Field desorption map 6.5.2 Mass spectrum 6.5.3 Multiple events 6.5.4 Discussion 7. Tomographic reconstruction 7.1 Projection of the ions 7.1.1 Estimation of the electric field 7.1.2 Field distribution 7.1.3 Ion trajectories 7.1.4 Point projection 7.1.5 Radial projection with angular compression 7.1.6 Discussion 7.2 Reconstruction 7.2.1 General considerations 7.2.2 Bas et al. protocol 7.2.3 Geiser et al. protocol 7.2.4 Gault et al. protocol 7.2.5 Reflectron-fitted instruments 7.2.6 Summary and discussion 7.3 Calibration of the parameters 7.3.2 Discussion 7.3.3 Limitations of the current procedure 7.4 Common artefacts 7.4.2 Correction of the reconstruction 7.5 Perspectives on the reconstruction in Atom Probe tomography 7.5.1 Advancing the reconstruction by correlative microscopy 7.5.2 In correlation with simulations 7.5.3 Alternative ways to exploit existing data 7.6 Spatial resolution in APT 7.6.1 Introduction 7.6.2 Means of investigation 7.6.3 Definition 7.6.4 On the in-depth resolution 7.6.5 On the lateral resolution 7.6.6 Optimisation of the spatial resolution 7.7 Lattice rectification PART III Applying Atom Probe techniques for materials science 8. Analysis techniques for Atom Probe tomography 8.1 Characterising the Mass Spectrum 8.1.1 Noise Reduction 8.1.2 Quantifying Peak Contributions via Isotope Natural Abundances 8.1.3 Spatially dependent identification of mass peaks 8.1.4 Multiple Detector Event Analyses 8.2 Characterising the chemical distribution 8.2.1 Quality of Atom Probe data 8.2.2 Random comparators 8.3 Grid-based counting statistics 8.3.1 Voxelisation 8.3.2 Density 8.3.3 Concentration analyses 8.3.4 Smoothing by delocalisation 8.3.5 Visualisation techniques based on iso-concentration and iso-density 8.3.6 One-dimensional profiles 8.3.7 Grid-based frequency distribution analyses 8.4 Techniques for describing Atomic architecture 8.4.1 Nearest neighbour distributions 8.4.2 Cluster Identification Algorithms 8.4.3 Detection Efficiency Influence on Nanostructural Analyses 8.5 Radial Distribution 8.5.1 Radial distribution and pair correlation functions 8.5.2 Solute Short Range Order Parameters 8.6 Structural Analyses 8.6.1 Fourier Transforms for APT 8.6.2 Spatial Distribution Maps 8.6.3 Hough Transform 9. Atom Probe microscopy and materials science 9.1 Compositional analysis 9.2 Defects/ dislocations 9.3 Solid solutions / clustering 9.4 Precipitates 9.5 Ordering reaction 9.6 Spinodal decomposition 9.7 Interface/boundaries/layers 9.8 Amorphous materials 9.9 Atom Probe crystallography Appendices A. Appendix - chi2 distribution B. Appendix - Polishing chemicals and conditions C. File formats used in APT POS EPOS RNG RRNG ATO ENV PoSAP Cameca root files - RRAW, RHIT, ROOT D. Appendix - Image Hump Model Predictions E. Appendix - Essential Crystallography for APT Bravais lattices Notation Structure factor (F) rules for BCC, FCC, HCP Interplanar spacings (dhkl) Interplanar angles (phi) F. Stereographic Projections and commonly observed desorption maps Stereographic projection for the most commonly found structures and orientations Face-centred cubic Body-centred cubic Diamond cubic Hexagonal close-packed G. Periodic tables H. Kingham Curves I. List of elements and associated mass to charge ratios J. Possible element identity of peaks as a function of their location in the mass spectrum

  • Experimental Protocols in Atom Probe Tomography
    Atom Probe Microscopy, 2012
    Co-Authors: Baptiste Gault, Michael P Moody, Julie M Cairney, Simon P Ringer
    Abstract:

    In this chapter, each step of an Atom Probe tomography experiment is described sequentially, from the alignment of the specimen to its probable fracture, which is the most usual termination of an experiment. The influence of the main experimental parameters—base temperature, detection rate, pulsing mode, etc.—is discussed with the aim of helping the Atom Probe user to understand the mechanisms underpinning how these parameters could change the data collected, and hence to select parameters to obtain the best possible data. A set of metrics is introduced that can be used to assess the quality of the data. Of these, several can be assessed as the analysis is being performed, including the measured composition within a dataset, the signal-to-background ratio, the quality of the field desorption map, or the amount of multiple events. Of course, the quality of the tomographic reconstruction is an a posteriori criterion.

  • The future of Atom Probe tomography
    Materials Today, 2012
    Co-Authors: Michael K Miller, Thomas F. Kelly, Krishna Rajan, Simon P Ringer
    Abstract:

    The dream of the microscopy and materials science communities is to see, identify, accurately locate, and determine the fundamental physical properties of every Atom in a specimen. With this knowledge together with modern computer models and simulations, a full understanding of the properties of a material can be determined. This fundamental knowledge leads to the design and development of more advanced materials for solving the needs of society. The technique of Atom Probe tomography is the closest to fulfilling this dream but is still significantly short of the goal. The future of Atom Probe tomography, and the prospects for achieving this ultimate goal are outlined.

  • Impact of laser pulsing on the reconstruction in an Atom Probe tomography.
    Ultramicroscopy, 2010
    Co-Authors: Baptiste Gault, Michael P Moody, Simon P Ringer, Alex La Fontaine, Emmanuelle A. Marquis
    Abstract:

    The implementation of fast pulsed laser has significantly improved the performance of the Atom Probe technique by enabling near-Atomic-scale three-dimensional analysis of poorly conducting materials. This has broadened the range of applications for the Atom Probe, addressing a major limitation of the technique. Despite this, the implications of lasing on the tomographic reconstruction of Atom Probe data have yet to be fully characterised. Here, we demonstrate how changes in the shape of the specimen surface, induced by laser pulsing, affect the ion trajectories, and hence the projection parameters used to build the three-dimensional map.