Electron channeling patterns in the scanning electron microscope

Joy, David C.; Newbury, Dale E.; Davidson, D. L.

doi:10.1063/1.331668

Cited by 326 publications

(145 citation statements)

References 99 publications

(35 reference statements)

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“…patterns (Alam et al, 1954;Venables and Harland, 1972;Dingley, 1981;; Dingley and Baba-Kishi, SELECTED area electron channelling patterns (Coates, 1990;Dingley and Randle, 1992;Randle, 1992;Day, 1967;Joy, 1974;Joy et al, 1982;Davidson, 1984; both provide quantitative data concerning Lloyd, 1985;1987;Schmidt and Olesen, 1989; Lloyd spatial variation of crystallographic orientations Lloyd, 1995) and electron backscatter minerals. In many problems relevant to geologists, Mineralogical Magazine, December 1996, Vol.…”

Section: Introductionmentioning

confidence: 99%

Orientation contrast imaging of microstructures in rocks using forescatter detectors in the scanning electron microscope

et al. 1996

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We have developed a system using 'forescatter detectors' for backscattered imaging of specimen surfaces inclined at 50-80 ~ to the incident beam (inclined-scanning) in the SEM. These detectors comprise semiconductor chips placed below the tilted specimen. Forescatter detectors provide an orientation contrast (OC) image to complement quantitative crystallographic data from electron backscatter patterns (EBSP). Specimens were imaged using two detector geometries and these images were compared to those collected with the specimen surface normal to the incident beam (normal-scanning) using conventional backscattered electron detector geometries and also to an automated technique, orientation imaging microscopy (DIM). When normal-scanning, the component of the BSE signal relating to the mean atomic number (z) of the material is an order of magnitude greater than any OC component, making OC imaging in polyphase specimens almost impossible. Images formed in inclined-scanning, using forescatter detectors, have OC and z-contrast signals of similar magnitude, allowing OC imaging in polyphase specimens.OC imaging is purely qualitative, and by repeatedly imaging the same area using different specimen-beam geometries, we found that a single image picks out less than 60% of the total microstructural information and as many as 6 combined images are required to give the full data set. The DIM technique is limited by the EBSP resolution (1-2 ~ and subsequently misses a lot of microstructural information. The use of forescatter detectors is the most practical means of imaging OC in tilted specimens, but it is also a powerful tool in its own right for imaging microstructures in polyphase specimens, an essential asset for geological work.KEYWORDS: contrast images, scanning electron microscopy, backscattered electrons. Introductionpatterns (Alam et al., 1954;Venables and Harland, 1972;Dingley, 1981;; Dingley and Baba-Kishi, SELECTED area electron channelling patterns (Coates, 1990;Dingley and Randle, 1992;Randle, 1992; Day, 1967;Joy, 1974;Joy et al., 1982;Davidson, 1984; both provide quantitative data concerning Lloyd, 1985;1987;Schmidt and Olesen, 1989; Lloyd spatial variation of crystallographic orientations Lloyd, 1995) and electron backscatter minerals. In many problems relevant to geologists,

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Section: Introductionmentioning

confidence: 99%

Orientation contrast imaging of microstructures in rocks using forescatter detectors in the scanning electron microscope

et al. 1996

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“…The authors would also like to thank Jared Shank, of UES, Inc., for his help in editing this paper. [19]). The electron backscatter signal intensity changes as a function of the angular deviation from the exact Bragg condition.…”

Section: Special Thanksmentioning

confidence: 99%

Electron Channeling: A Problem for X-Ray Microanalysis in Materials Science

et al. 2009

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The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Department of Defense, Washington Headquarters Services, Directorate for Information SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)Air Force Research Laboratory SPONSORING/MONITORING AGENCY ACRONYM(S)Materials and DISTRIBUTION/AVAILABILITY STATEMENTApproved for public release; distribution unlimited. SUPPLEMENTARY NOTESJournal article submitted to Microscopy and Microanalysis. PAO Case Number: WPAFB 08-3283; Clearance Date: 14 May 2008. The U.S. Government is joint author of this work and has the right to use, modify, reproduce, release, perform, display, or disclose the work. Paper contains color. ABSTRACTElectron channeling effects, within the scanning electron microscope, are expected to create measurable signal intensity variations in all product signals that result from the scattering of the electron beam within a crystalline specimen. Of particular interest to the x-ray microanalyst, are any variations that occur within the characteristic x-ray signal that are not directly related to a specimen composition variation. Thus many researcher have worked to document the effect of crystallographic orientation on the local x-ray yield produced by a specimen. However, the vast majority of these studies were carried out in regards to thin foil specimens examine in transmission. Only a few x-ray microanalysis studies specifically addressed these effects in bulk specimen materials, and the analyses were generally carried out 35 to 40 years ago, at common scanning electron microscope, microanalysis overvoltage (>1.5). At these overvoltage levels, the anomalous transmission effect is generally very weak (typically <5% difference between intensity maxima and minima). SUBJECT TERMS AbstractElectron channeling effects, within the scanning electron microscope, are expected to create measurable signal intensity variations in all product signals that result from the scattering of the electron beam within a crystalline specimen. Of particular interest to the x-ray microanalyst, are any variations that occur within the characteristic x-ray signal that are not directly related to a specimen composition variation. Thus many researchers have worked to document the effect of crystallographic orientation on the local x-ray yield produced by a specimen. However, the vast majority of these studies were carried out in regards to thin foil specimens examined in transmission. Only a few x-ray microanalysis studies specifically addressed these effects in bulk specimen materials, and the analyses were generally carried out 35-40 years ago, at common scanning ele...

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“…Strikingly, the observed patterns have a negative intensity distribution relative to what is usually observed for backscattered electrons from the sample in the SEM. As we will show by comparison to simulations, these patterns can be interpreted as electron channeling patterns 23 which are formed not by the sample but in the Timepix detector crystal itself. The observation of these "detector diffraction patterns" (DDP) means that the Timepix detector can serve as an array of directionally sensitive pixels in the context of the diffractive triangulation principle introduced above.…”

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confidence: 99%

“…This is due to the preferential excitation of Bloch waves that are localized on lattice planes or between them. 23 In correspondence with the incident beam diffraction effects, the excitation of electron-hole pairs in each silicon pixel element (the measured signal) will be varying as a function of incidence angle. Because less electrons penetrate into the crystal when there is a large backscattered signal, the observed DDP is inversely proportional to the backscattered intensity, compare Figs.…”

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confidence: 99%

Diffractive triangulation of radiative point sources

Vespucci

Naresh-Kumar

Trager-Cowan

et al. 2017

Applied Physics Letters

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We describe a general method to determine the location of a point source of waves relative to a two-dimensional single-crystalline active pixel detector. Based on the inherent structural sensitivity of crystalline sensor materials, characteristic detector diffraction patterns can be used to triangulate the location of a wave emitter. The principle described here can be applied to various types of waves provided that the detector elements are suitably structured. As a prototypical practical application of the general detection principle, a digital hybrid pixel detector is used to localize a source of electrons for Kikuchi diffraction pattern measurements in the scanning electron microscope. This approach provides a promising alternative method to calibrate Kikuchi patterns for accurate measurements of microstructural crystal orientations, strains, and phase distributions

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Electron channeling patterns in the scanning electron microscope

Cited by 326 publications

References 99 publications

Orientation contrast imaging of microstructures in rocks using forescatter detectors in the scanning electron microscope

Orientation contrast imaging of microstructures in rocks using forescatter detectors in the scanning electron microscope

Electron Channeling: A Problem for X-Ray Microanalysis in Materials Science

Diffractive triangulation of radiative point sources

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