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SUMMARY:Exit Wave Restoration: Methods and Applications - Shery Chang\, De
 partment of Materials\, University of Oxford
DTSTART:20060516T140000Z
DTEND:20060516T150000Z
UID:TALK4884@talks.cam.ac.uk
CONTACT:Edmund Ward
DESCRIPTION:To achieve higher resolution and improved interpretability in 
 electron microscopy\, indirect restoration of the specimen exit plane wave
 function is currently widely used. There are a few methods available\, and
  the major difference between these methods is the assumptions on the cohe
 rence effects. I will focus on two of the methods: Wiener filter and the M
 aximum Likelihood (MAL) algorithm. The former applies linear imaging appro
 ximation (strong central beam)\, whereas the latter is more general. Both 
 algorithms on the simulated and experimental data will be discussed and co
 mpared.\n   \nOn the other hand\, exit wave restoration can be achieved by
  using a series of images at either different defoci or beam tilts. Focal 
 series restoration is a much more popular method as the acquisition of ima
 ges at different defocus is easier in a conventional electron microscope. 
 However\, with the aberration-corrected electron microscope\, tilt series 
 acquisition is equally straightforward as focus series\, and the tilt seri
 es has an advantage of better resolution over the focus series.\nExamples 
 of exit wave restoration on the two material systems will be shown to demo
 nstrate the power of the technique. The restorations of the peapod structu
 re of Sc3N@C68@SWNT and catalytic Pt nanoparticles will be discussed.\n \n
 Finally\, the interpretation\, and extension of the exit wave restoration 
 and its limit will be discussed.\n
LOCATION:T001 [Tower Seminar Room]\, Materials Science and Metallurgy\, De
 partment of
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