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Masashi Wantanabe

Toward Quantitative Analysis of Atomic-Resolution X-ray Maps in an Aberration- Corrected Scanning Transmission Electron Microscope with a Large Solid- Angle Detector

Masashi WatanabeDept of Materials Science and Engineering, Lehigh University, Bethlehem. PA 18015.


Materials characterization is now routinely performed at atomic resolution by high-angle annular dark-field (HAADF) imaging and electron energy-loss spectroscopy (EELS) analysis in aberration-corrected scanning transmission electron microscopes (STEMs). A use of the aberration-corrected fine probe is ideal for X-ray energy-dispersive spectrometry (XEDS) since more probe current can be added into the incident probe. In addition, the latest silicon drift detectors (SDDs) are employed with new configurations around an objective pole-piece area for enhancement of the X-ray detection efficiency. The new detector configurations integrated to aberration-corrected instruments allow us to acquire X-ray maps with atomic spatial resolution.


In this talk, the current status of X-ray analysis in terms of analytical sensitivity and spatial resolution will be reviewed. Then, challenges for quantification in atomic-resolution X-ray analysis will be discussed.



Masashi Watanabe is an Associate Professor at Department of Materials Science and Engineering in Lehigh University since 2009. He obtained his Ph.D. in Metallurgy from Kyushu University in 1996 and was a postdoctoral research associate at Lehigh until 1998. He was an Associate Professor at Research Laboratory for High Voltage Electron Microscopy (HVEM) in Kyushu in 1998 until he returned to Lehigh University as a Research Scientist in 2001. In March 2007, he joined to National Center for Electron Microscopy (NCEM) in Lawrence Berkeley National Laboratory (LBNL) as a Staff Scientist mainly assigned for analytical electron microscopy. At NCEM, he also participated in the TEAM project. 


Masashi received the K.F.J. Heinrich young scientist award from the Microbeam Analysis Society in 2005, the Kazato Prize from the Kazato Research Foundation in 2008 and the Seto Award (the Society Award) from the Japanese Society of Microscopy in 2011. He has been a lecturer in the AEM course at the Lehigh Microscopy School since 2001 and in the Arizona State University Winter School on High Resolution Electron Microscopy since 2008. He has published over 150 articles and his MSA plug-in package for Gatan DigitalMicrograph is now commercialized from HREM Research Inc. since 2009. Masashi's research emphasizes materials characterization using various electron microscopy approaches involving analysis via X-rays and energy-loss electrons in analytical electron microscopes (AEMs) and atomic-resolution high angle annular dark-filed (HAADF) imaging in scanning transmission electron microscopes (STEMs). He developed the z (zeta)-factor method for quantitative X-ray analysis and implemented multivariate statistical analysis (MSA) for spectrum images of X-rays and energy-loss electrons.

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