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==Pattern formation and collection==
=== Setup geometry and pattern formation ===
{{Further information|Electron diffraction|Kikuchi lines (physics)}}[[File:EBSD setup.tif|thumb|EBSD typical hardware configuration inside [[field emission gun scanning electron microscope]] (FEG-SEM). The EBSD detector has a Forward scattered electron didoes (FSD) at the bottom. MSD note only the position of the diode as being in the middle (M). Othe detectors has a Backscatter diodes (BSD) at the top of the EBSD detector. An image created using a combination of diodes are called VFSD or virtual.<ref name=":34">{{Cite journal |last=Wright |first=Stuart I. |last2=Nowell |first2=Matthew M. |last3=de Kloe |first3=René |last4=Camus |first4=Patrick |last5=Rampton |first5=Travis |date=2015-01-01 |title=Electron imaging with an EBSD detector |url=https://www.sciencedirect.com/science/article/pii/S0304399114001946 |journal=Ultramicroscopy |language=en |volume=148 |pages=132–145 |doi=10.1016/j.ultramic.2014.10.002 |issn=0304-3991}}</ref> ]]
For electron backscattering diffraction microscopy, a flat polished crystalline specimen is usually placed inside a [[scanning electron microscope]] (SEM) chamber, tilted ~70° from SEM original specimen positioning and 110° to the diffraction camera.<ref name=":18">{{Cite journal |last=Randle |first=Valerie |date=September 2009 |title=Electron backscatter diffraction: Strategies for reliable data acquisition and processing |url=https://linkinghub.elsevier.com/retrieve/pii/S1044580309001879 |journal=Materials Characterization |language=en |volume=60 |issue=9 |pages=913–922 |doi=10.1016/j.matchar.2009.05.011 |access-date=2023-03-02 |archive-date=2023-01-21 |archive-url=https://web.archive.org/web/20230121170149/https://linkinghub.elsevier.com/retrieve/pii/S1044580309001879 |url-status=live }}</ref> Tilting the sample elongates the interaction volume perpendicular to the tilt axis, allowing more electrons to leave the sample due to elastic scattering, providing better contrast.<ref>{{Citation |last1=Goldstein |first1=Joseph I. |title=Backscattered Electrons |date=2018 |url=http://link.springer.com/10.1007/978-1-4939-6676-9_2 |work=Scanning Electron Microscopy and X-Ray Microanalysis |pages=15–28 |place=New York, NY |publisher=Springer New York |language=en |doi=10.1007/978-1-4939-6676-9_2 |isbn=978-1-4939-6674-5 |access-date=2023-03-02 |last2=Newbury |first2=Dale E. |last3=Michael |first3=Joseph R. |last4=Ritchie |first4=Nicholas W. M. |last5=Scott |first5=John Henry J. |last6=Joy |first6=David C. |archive-date=2023-03-03 |archive-url=https://web.archive.org/web/20230303214038/https://link.springer.com/chapter/10.1007/978-1-4939-6676-9_2 |url-status=live }}</ref><ref>{{Cite journal |last1=Winkelmann |first1=Aimo |last2=Nolze |first2=Gert |date=February 2010 |title=Analysis of Kikuchi band contrast reversal in electron backscatter diffraction patterns of silicon |url=https://linkinghub.elsevier.com/retrieve/pii/S0304399109002538 |journal=Ultramicroscopy |language=en |volume=110 |issue=3 |pages=190–194 |doi=10.1016/j.ultramic.2009.11.008 |pmid=20005045 |access-date=2023-03-02 |archive-date=2022-10-24 |archive-url=https://web.archive.org/web/20221024075755/https://linkinghub.elsevier.com/retrieve/pii/S0304399109002538 |url-status=live }}</ref> The high-energy electron beam (typically 20 kV) is focused on a small volume and scatters at a spatial resolution of ~20 nm at the specimen surface.<ref name=":0">{{Citation |last1=Schwarzer |first1=Robert A. |title=Present State of Electron Backscatter Diffraction and Prospective Developments |date=2009 |url=https://doi.org/10.1007/978-0-387-88136-2_1 |work=Electron Backscatter Diffraction in Materials Science |pages=1–20 |editor-last=Schwartz |editor-first=Adam J. |place=Boston, MA |publisher=Springer US |language=en |doi=10.1007/978-0-387-88136-2_1 |isbn=978-0-387-88136-2 |access-date=2023-03-02 |last2=Field |first2=David P. |last3=Adams |first3=Brent L. |last4=Kumar |first4=Mukul |last5=Schwartz |first5=Adam J. |osti=964094 |editor2-last=Kumar |editor2-first=Mukul |editor3-last=Adams |editor3-first=Brent L. |editor4-last=Field |editor4-first=David P. |archive-date=2023-03-03 |archive-url=https://web.archive.org/web/20230303225548/https://link.springer.com/chapter/10.1007/978-0-387-88136-2_1 |url-status=live }}</ref> The spatial resolution varies with angular width,<ref>{{Cite journal |last1=Venables |first1=J. A. |last2=Harland |first2=C. J. |date=1973-05-01 |title=Electron back-scattering patterns—A new technique for obtaining crystallographic information in the scanning electron microscope |url=https://doi.org/10.1080/14786437308225827 |journal=The Philosophical Magazine: A Journal of Theoretical Experimental and Applied Physics |volume=27 |issue=5 |pages=1193–1200 |doi=10.1080/14786437308225827 |bibcode=1973PMag...27.1193V |issn=0031-8086 |access-date=2023-03-02 |archive-date=2023-03-03 |archive-url=https://web.archive.org/web/20230303225533/https://www.tandfonline.com/doi/abs/10.1080/14786437308225827?cookieSet=1 |url-status=live }}</ref> interaction volume,<ref>{{Cite journal |last1=Chen |first1=Delphic |last2=Kuo |first2=Jui-Chao |last3=Wu |first3=Wen-Tuan |date=2011-08-01 |title=Effect of microscopic parameters on EBSD spatial resolution |url=https://www.sciencedirect.com/science/article/pii/S030439911100177X |journal=Ultramicroscopy |language=en |volume=111 |issue=9 |pages=1488–1494 |doi=10.1016/j.ultramic.2011.06.007 |pmid=21930021 |issn=0304-3991}}</ref> nature of the material under study,<ref name=":0" /> and in transmission Kikuchi diffraction with the specimen thickness;<ref>{{Cite journal |year=2005 |title=Improving the Spatial Resolution of EBSD |url=https://academic.oup.com/mam/article/11/S02/52/6915128 |access-date=2023-03-02 |journal=Microscopy and Microanalysis |doi=10.1017/s1431927605506445 |last1=Field |first1=D. P. |volume=11 |s2cid=138097039 |archive-date=2023-03-02 |archive-url=https://web.archive.org/web/20230302110428/https://academic.oup.com/mam/article/11/S02/52/6915128 |url-status=live }}</ref> thus, increasing the beam energy increases the interaction volume and decreases the spatial resolution.<ref>{{Cite journal |last1=Deal |first1=Andrew |last2=Tao |first2=Xiaodong |last3=Eades |first3=Alwyn |date=November 2005 |title=EBSD geometry in the SEM: simulation and representation |url=https://onlinelibrary.wiley.com/doi/10.1002/sia.2115 |journal=Surface and Interface Analysis |language=en |volume=37 |issue=11 |pages=1017–1020 |doi=10.1002/sia.2115 |s2cid=122757345 |issn=0142-2421}}</ref>
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The biggest advantage of the high-resolution detectors is their higher sensitivity and therefore the information within each diffraction pattern can be analysed in more detail. For texture and orientation measurements, the diffraction patterns are binned in order to reduce their size and reduce computational times. Modern CCD-based EBSD systems can index patterns at up to 1800 patterns/second. This enables very rapid and rich microstructural maps to be generated.<ref name=":20" /><ref name=":15" />
[[File:VFSD image of DSS.jpg|thumb|Virtual Forward scattered electron (VFSD) image of [[475 °C embrittlement|475 °C embrittled]] [[Duplex stainless steel]]]]
EBSD detectors can have a Forward scattered electron
=== Sample preparation ===
Ideally, the sample should be vacuum-stable and mounted using a conductive compound (e.g. Cu and [[Silicon dioxide|SiO<sub>2</sub>]] filled epoxy thermoset) because it minimises image drift and the intensity blooming caused by the electron beam charging. Due to EBSPs quality being highly sensitive to the surface preparation, the sample should be ground using [[Sandpaper|SiC papers]] from 240 down to 4000 grit, and polished using diamond paste (from 9 to 1 µm) then in 50 nm [[colloidal silica]] for 2 hours (50rpm speed and 5N force) to produce a flat surface without preparation-induced artefacts and also to maintain consistency – for comparison – between samples. Afterwards, the sample should be cleaned for 20 minutes in Ultrasonic cleaning bath using [[ethanol]], then rinsed with [[deionised water]], before eventually being dried with a hot air blower. This is followed by ion polishing, for final surface preparation, using 7.5 keV dual beam energy for 15 min, with the gun’s angle of 8°.<ref>{{Cite journal |last1=Nowell |first1=Matthew M |last2=Witt |first2=Ronald A |last3=True |first3=Brian W |date=2005-07-01 |title=EBSD Sample Preparation: Techniques, Tips, and Tricks |url=http://dx.doi.org/10.1017/s1551929500053669 |journal=Microscopy Today |volume=13 |issue=4 |pages=44–49 |doi=10.1017/s1551929500053669 |s2cid=139585885 |issn=2150-3583 |access-date=2023-03-03 |archive-date=2023-03-03 |archive-url=https://web.archive.org/web/20230303225551/https://academic.oup.com/mt/article/13/4/44/6822053 |url-status=live }}</ref><ref name=":32">{{Cite journal |last1=Koko |first1=Abdalrhaman |last2=Elmukashfi |first2=Elsiddig |last3=Becker |first3=Thorsten H. |last4=Karamched |first4=Phani S. |last5=Wilkinson |first5=Angus J. |last6=Marrow |first6=T. James |date=2022-10-15 |title=In situ characterisation of the strain fields of intragranular slip bands in ferrite by high-resolution electron backscatter diffraction |url=https://www.sciencedirect.com/science/article/pii/S1359645422006644 |journal=Acta Materialia |language=en |volume=239 |pages=118284 |doi=10.1016/j.actamat.2022.118284 |bibcode=2022AcMat.23918284K |s2cid=251783802 |issn=1359-6454 |access-date=2023-03-03 |archive-date=2022-10-07 |archive-url=https://web.archive.org/web/20221007215651/https://www.sciencedirect.com/science/article/pii/S1359645422006644 |url-status=live }}{{Creative Commons text attribution notice|cc=by4|from this source=yes}}</ref><ref>{{Cite web |date=2013-11-15 |title=Sample Preparation Techniques for EBSD Analysis (Electron Backscatter Diffraction) |url=https://www.azonano.com/article.aspx?ArticleID=3702 |access-date=2023-03-03 |website=AZoNano.com |language=en |archive-date=2023-03-02 |archive-url=https://web.archive.org/web/20230302142456/https://www.azonano.com/article.aspx?ArticleID=3702 |url-status=live }}</ref>
Inside the scanning electron microscope (SEM), the size of the measurement area determines local resolution and measurement time.<ref>{{Cite book |last=B. |first=Williams, David |url=http://worldcat.org/oclc/633626308 |title=Transmission electron microscopy : a textbook for materials science. |date=2009 |publisher=Plenum Press |isbn=978-0-387-76501-3 |oclc=633626308 |access-date=2023-03-03 |archive-date=2023-03-03 |archive-url=https://web.archive.org/web/20230303225557/https://worldcat.org/title/633626308 |url-status=live }}</ref> For high-quality EBSPs, it is recommended<ref>{{Cite journal |last1=Britton |first1=T.B. |last2=Jiang |first2=J. |last3=Clough |first3=R. |last4=Tarleton |first4=E. |last5=Kirkland |first5=A.I. |last6=Wilkinson |first6=A.J. |date=2013-12-01 |title=Assessing the precision of strain measurements using electron backscatter diffraction – Part 2: Experimental demonstration |url=http://dx.doi.org/10.1016/j.ultramic.2013.08.006 |journal=Ultramicroscopy |volume=135 |pages=136–141 |doi=10.1016/j.ultramic.2013.08.006 |pmid=24034981 |issn=0304-3991 |access-date=2023-03-03 |archive-date=2023-03-03 |archive-url=https://web.archive.org/web/20230303225556/https://www.sciencedirect.com/science/article/abs/pii/S030439911300212X?via%3Dihub |url-status=live }}</ref><ref>{{Cite journal |last1=Jiang |first1=J. |last2=Britton |first2=T.B. |last3=Wilkinson |first3=A.J. |date=2013-11-01 |title=Evolution of dislocation density distributions in copper during tensile deformation |url=http://dx.doi.org/10.1016/j.actamat.2013.08.027 |journal=Acta Materialia |volume=61 |issue=19 |pages=7227–7239 |doi=10.1016/j.actamat.2013.08.027 |bibcode=2013AcMat..61.7227J |issn=1359-6454 |access-date=2023-03-03 |archive-date=2023-03-03 |archive-url=https://web.archive.org/web/20230303225539/https://www.sciencedirect.com/science/article/abs/pii/S135964541300623X?via%3Dihub |url-status=live }}</ref><ref>{{Cite journal |last1=Abdolvand |first1=Hamidreza |last2=Wilkinson |first2=Angus J. |date=2016-09-01 |title=On the effects of reorientation and shear transfer during twin formation: Comparison between high resolution electron backscatter diffraction experiments and a crystal plasticity finite element model |url=http://dx.doi.org/10.1016/j.ijplas.2016.05.006 |journal=International Journal of Plasticity |volume=84 |pages=160–182 |doi=10.1016/j.ijplas.2016.05.006 |s2cid=139049848 |issn=0749-6419 |access-date=2023-03-03 |archive-date=2023-03-03 |archive-url=https://web.archive.org/web/20230303225542/https://www.sciencedirect.com/science/article/pii/S0749641916300808?via%3Dihub |url-status=live }}</ref><ref name=":29">{{Cite journal |last1=Koko |first1=Abdalrhaman |last2=Becker |first2=Thorsten H. |last3=Elmukashfi |first3=Elsiddig |last4=Pugno |first4=Nicola M. |last5=Wilkinson |first5=Angus J. |last6=Marrow |first6=T. James |date=2023-03-01 |title=HR-EBSD analysis of in situ stable crack growth at the micron scale |url=https://www.sciencedirect.com/science/article/pii/S0022509622003490 |url-status=live |journal=Journal of the Mechanics and Physics of Solids |language=en |volume=172 |pages=105173 |arxiv=2206.10243 |bibcode=2023JMPSo.17205173K |doi=10.1016/j.jmps.2022.105173 |issn=0022-5096 |archive-url=https://web.archive.org/web/20230201164705/https://www.sciencedirect.com/science/article/pii/S0022509622003490 |archive-date=2023-02-01 |access-date=2023-03-03 |s2cid=249889649}}</ref> to use 15 nA current, 20 keV beam energy, 18mm working distance, long exposure times and minimal pattern binning. The EBSD phosphor screen should be also at 18mm working distance with at least 800*600 resolution, 180 milli-seconds exposure time per pattern, 2*2 pattern binning, and a map’s step size less than 0.5µm.<ref name=":30" /><ref name=":31" />[[File:EBSP degradation.tif|thumb|Pattern degradation due to carbon deposition in a highly magnified location after 3hr EBSPs acquisition around a deformation twin in the ferrite phase of duplex stainless steel.<ref name=":31" />]]
The effect of carbon deposition on the quality of the patterns, which is caused by the electron-beam-induced decomposition of gaseous hydrocarbons during slow EBSPs acquisition.<ref>{{Cite journal |last1=Griffiths |first1=A J V |last2=Walther |first2=T |date=2010-07-01 |title=Quantification of carbon contamination under electron beam irradiation in a scanning transmission electron microscope and its suppression by plasma cleaning |url=https://doi.org/10.1088/1742-6596/241/1/012017 |journal=Journal of Physics: Conference Series |volume=241 |issue=1 |pages=012017 |bibcode=2010JPhCS.241a2017G |doi=10.1088/1742-6596/241/1/012017 |issn=1742-6596 |s2cid=250689401}}</ref> Carbon depositions degrade the quality of EBSPs inside the probed area compared to the EBSPs outside the acquisition window. The gradient of pattern degradation increases moving inside the probed zone with an apparent accumulation of deposited carbon. The black spots from the beam instant-induced carbon deposition also highlight the immediate deposition even if agglomeration did not happen.<ref name=":4">{{Cite journal |last1=Koko |first1=Abdalrhaman |last2=Elmukashfi |first2=Elsiddig |last3=Dragnevski |first3=Kalin |last4=Wilkinson |first4=Angus J. |last5=Marrow |first5=Thomas James |date=2021-10-01 |title=J-integral analysis of the elastic strain fields of ferrite deformation twins using electron backscatter diffraction |url=https://www.sciencedirect.com/science/article/pii/S1359645421005838 |journal=Acta Materialia |language=en |volume=218 |pages=117203 |bibcode=2021AcMat.21817203K |doi=10.1016/j.actamat.2021.117203 |issn=1359-6454}}</ref><ref name=":12">{{Cite journal |last1=Bachmann |first1=F. |last2=Hielscher |first2=Ralf |last3=Schaeben |first3=Helmut |date=2010-02-03 |title=Texture Analysis with MTEX – Free and Open Source Software Toolbox |url=https://www.scientific.net/SSP.160.63 |url-status=live |journal=Solid State Phenomena |language=en |volume=160 |pages=63–68 |doi=10.4028/www.scientific.net/SSP.160.63 |issn=1662-9779 |archive-url=https://web.archive.org/web/20230302180143/https://www.scientific.net/SSP.160.63 |archive-date=2023-03-02 |access-date=2023-03-02 |s2cid=136017346}}</ref>
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