Porosity detection in electron beam-melted Ti-6Al-4V using high-resolution neutron imaging and grating-based interferometry

The scanning electron microscope (SEM) builds up an image by sampling contiguous sub-volumes near the surface of the specimen. A fine electron beam selectively excites each sub-volume and then the intensity of some resulting signal is measured. The spatial resolution of images made using such a process is limited by at least three factors. Two of these determine the size of the interaction volume: the size of the electron probe and the extent to which detectable signal is excited from locations remote from the beam impact point. A third limitation emerges from the fact that the probing beam is composed of a finite number of discrete particles and therefore that the accuracy with which any detectable signal can be measured is limited by Poisson statistics applied to this number (or to the number of events actually detected if this is smaller).

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The method of replication affects metal film granularity and resolution

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100155517 ◽

1989 ◽

Vol 47 ◽

pp. 708-709

Author(s):

George C. Ruben

Keyword(s):

Electron Beam ◽

High Resolution ◽

Film Thickness ◽

Single Molecule ◽

Metal Film ◽

Vertical Surface ◽

High Resolution Imaging ◽

Controllable Factors ◽

Resolution Imaging

Single molecule resolution in electron beam sensitive, uncoated, noncrystalline materials has been impossible except in thin Pt-C replicas ≤ 150Å) which are resistant to the electron beam destruction. Previously the granularity of metal film replicas limited their resolution to ≥ 20Å. This paper demonstrates that Pt-C film granularity and resolution are a function of the method of replication and other controllable factors. Low angle 20° rotary , 45° unidirectional and vertical 9.7±1 Å Pt-C films deposited on mica under the same conditions were compared in Fig. 1. Vertical replication had a 5A granularity (Fig. 1c), the highest resolution (table), and coated the whole surface. 45° replication had a 9Å granulartiy (Fig. 1b), a slightly poorer resolution (table) and did not coat the whole surface. 20° rotary replication was unsuitable for high resolution imaging with 20-25Å granularity (Fig. 1a) and resolution 2-3 times poorer (table). Resolution is defined here as the greatest distance for which the metal coat on two opposing faces just grow together, that is, two times the apparent film thickness on a single vertical surface.

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High-resolution observation of sintered alumina (Al2O3) using the specimen-heated and electron-beam-induced conductivity method in a UHR-SEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100172966 ◽

1994 ◽

Vol 52 ◽

pp. 1046-1047

Author(s):

K. Ogura ◽

T. Suzuki ◽

C. Nielsen

Keyword(s):

Electron Beam ◽

High Resolution ◽

Specimen Preparation ◽

Conductivity Method ◽

Fine Grain ◽

Grain Structures ◽

Resolution Observation ◽

Electron Microscopes ◽

Scanning Electron Microscopes ◽

Charging Effect

In spite of the complicated specimen preparation, Transmission Electron Microscopes (TEM) have traditionally been used for the investigation of the fine grain structures of sintered ceramics. Scanning Electron Microscopes (SEM) have not been used much for the same purpose as TEM because of poor results caused by the specimen charging effect, and also the lack of sufficient resolution. Here, we are presenting a successful result of high resolution imaging of sintered alumina (pure Al2O3) using the Specimen Heated and Electron Beam Induced Conductivity (SHEBIC) method, which we recently reported, in an ultrahigh resolution SEM (UHR-SEM). The JSM-6000F, equipped with a Field Emission Gun (FEG) and an in-lens specimen position, was used for this application.After sintered Al2O3 was sliced into a piece approximately 0.5 mm in thickness, one side was mechanically polished to get a shiny plane for the observation. When the observation was started at 20 kV, an enormous charging effect occured, and it was impossible to obtain a clear Secondary Electron (SE) image (Fig.1).

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Quantitative high-resolution electron microscopy (HREM) of defects in ordered polymers

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100163290 ◽

1996 ◽

Vol 54 ◽

pp. 166-167

Author(s):

Patricia M. Wilson ◽

David C. Martin

Keyword(s):

Electron Microscopy ◽

Electron Beam ◽

High Resolution ◽

Liquid Crystalline ◽

High Resolution Electron Microscopy ◽

Polymer Materials ◽

Scattered Electron ◽

Crystalline Polymers ◽

Resolution Electron ◽

Beam Damage

Efforts in our laboratory and elsewhere have established the utility of low dose high resolution electron microscopy (HREM) for imaging the microstructure of crystalline and liquid crystalline polymers. In a number of polymer systems, direct imaging of the lattice spacings by HREM has provided information about the size, shape, and relative orientation of ordered domains in these materials. However, because of the extent of disorder typical in many polymer microstructures, and because of the sensitivity of most polymer materials to electron beam damage, there have been few studies where the contrast observed in HREM images has been analyzed in a quantitative fashion.Here, we discuss two instances where quantitative information about HREM images has been used to provide new insight about the organization of crystalline polymers in the solid-state. In the first, we study the distortion of the polymer lattice planes near the core of an edge dislocation and compare these results to theories of dislocations in anisotropic and liquid crystalline solids. In the second, we investigate the variations in HREM contrast near the edge of wedge-shaped samples. The polymer used in this study was the diacetylene DCHD, which is stable to electron beam damage (Jc = 20 C/cm2) and highly crystalline. The instrument used in this work was a JEOL 4000 EX HRTEM with a beam blanidng device. More recently, the 4000 EX has been installed with instrumentation for dynamically recording scattered electron beam currents.

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High-resolution neutron imaging: a new approach to characterize water in anodic aluminum oxides

Materials Today Advances ◽

10.1016/j.mtadv.2020.100121 ◽

2020 ◽

Vol 8 ◽

pp. 100121

Author(s):

Noémie Ott ◽

Claudia Cancellieri ◽

Pavel Trtik ◽

Patrik Schmutz

Keyword(s):

High Resolution ◽

Neutron Imaging ◽

Aluminum Oxides ◽

New Approach ◽

Anodic Aluminum

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Neutron Imaging Using a Fine-Grained Nuclear Emulsion

Journal of Imaging ◽

10.3390/jimaging7010004 ◽

2021 ◽

Vol 7 (1) ◽

pp. 4

Author(s):

Katsuya Hirota ◽

Tomoko Ariga ◽

Masahiro Hino ◽

Go Ichikawa ◽

Shinsuke Kawasaki ◽

...

Keyword(s):

Image Analysis ◽

High Resolution ◽

Neutron Detector ◽

Nuclear Emulsion ◽

Neutron Imaging ◽

The Other ◽

Crystal Oscillator ◽

Fine Grained ◽

Cold Neutrons ◽

Track Analysis

A neutron detector using a fine-grained nuclear emulsion has a sub-micron spatial resolution and thus has potential to be applied as high-resolution neutron imaging. In this paper, we present two approaches to applying the emulsion detectors for neutron imaging. One is using a track analysis to derive the reaction points for high resolution. From an image obtained with a 9 μm pitch Gd grating with cold neutrons, periodic peak with a standard deviation of 1.3 μm was observed. The other is an approach without a track analysis for high-density irradiation. An internal structure of a crystal oscillator chip, with a scale of approximately 30 μm, was able to be observed after an image analysis.

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