Webinar: Bringing EDS to life: sample considerations for biological element analysis – October 2nd!

Oxford Instruments webcast

 

The MCF will broadcast this webinar on the monitor in the lobby of the MCF in the Marcus Nanotechnology Building.

It will be streamed on Wednesday, October 2nd from 11:00AM-12:00PM. If you would like to watch it at your own computer, you can register for the webinar here!

Energy dispersive X-ray spectrometry (EDS) provides biologists with colourful element-based compositional information in addition to greyscale ultrastructural data produced with standard electron microscopy (EM), aiding the correct identification of structures and labels. A crucial aspect of all biological EM, including EDS, is the preparation of specimens with the aim of preserving and imaging samples as close to their living state as possible. The best option is freezing samples rapidly and imaging them in their frozen-hydrated state. However, the samples are sensitive to the electron beam requiring low dose imaging methods to avoid damage, and the low contrast makes identification of ultrastructure difficult. Chemical fixation allows the addition of contrasting agents and provides greater stability in samples, but prolonged preparation techniques may result in changes to ultrastructure and potential extraction of elements.

In this webcast, the speakers will discuss the challenges of biological EDS and provide information about sample preparation methods and imaging conditions in order to maximise results — from traditionally prepared samples to unstained specimens to cryo-electron microscopy of vitrified samples (CEMOVIS) — to identify and image cell ultrastructure in both transmission and scanning electron microscopy.

 

MCF Lecture Series – Scanning Transmission Electron Microscopy – Technology and Applications 

MCF Technical Lecture Series: 

  • Thursday, December 14th 12:00 – 1:30 (NOTE TIME CORRECTION!)
  • Paper Tricentennial Building Seminar Hall – Room 114
  • Pizza and Drinks will be served 

Scanning Transmission Electron Microscopy – Technology and Applications 

C.T. (Tom) Schamp, Ph.D. 

Principal Consulting Scientist 

Materials Analytical Services, LLC 

Suwanee, GA 

 

The Scanning Transmission Electron Microscope (STEM) has evolved from a niche research-lab apparatus to arguably the leading electron microscopy analysis technique humanity has devised. In this presentation, I will discuss general principals of the STEM and aberration correction with an emphasis on making the concepts readily accessible. Then I will discuss examples of how the STEM is being or has been used to obtain data from nearly every conceivable signal available, including three-dimensional data.  

 

 

 

Two TEM/STEM related Seminars This Friday (May 20) Marcus 1116

Seminar 1       

Putting the back focal plane back into STEM: fun with fast pixelated detectors

Dr. Ian MacLaren

University of Glasgow, School of Physics and Astronomy

Location: Marcus Nanotechnology building Rm1116,

Time: May 20, 2016 2:30PM

Abstract:  STEM has typically used HAADF imaging for a very simple and interpretable contrast.  In recent years, there has also been a resurgence of interest in bright field and annular bright field imaging in STEM in order to see lighter atoms.  However, there is much more information than this in the back focal plane, and with the advent of fast direct electron detectors, it is now possible to actually record large amounts of the back focal plane and then process the dataset to extract a variety of kinds of information.  We show the uses of this for mapping magnetic fields in materials, imaging biological structures, performing atomic resolution phase-contrast imaging, and for mapping the 3D ordering in crystals.  As part of the talk, we will discuss the integration of such a detector into a modern analytical STEM, as well as how we are dealing with data handling and processing.

Seminar 2

High Temperature Corrosion Studies of Zircaloy- 4

Kirsty Annand

University of Glasgow, School of Physics and Astronomy

Abstract: Worldwide, Zircaloy-4 (Zr-1.5%Sn-0.2%Fe-0.1%Cr) is a popular material of choice for the containment of nuclear fuel and other structural components within commercial Pressurised Water Reactors (PWRs). However, waterside corrosion of these cladding materials results in the creation of an oxide layer on the surface of the metal, which degrades these containment vessels over time.

Using dual-range electron energy loss spectroscopy (DualEELS) on a GIF Quantum mounted on our JEOL ARM200F scanning transmission electron microscope, we have studied the evolution of the corrosion of Zircaloy-4 with time under simulated PWR conditions, using FIB preparation of cross sections through the oxide scale. This allowed us to simultaneously study changes in chemical composition and dielectric function of the material at the oxide scale – metal interface with nanometre resolution.  This has allowed the correlation of the appearance of different distinct phases with the zirconium-oxygen ratio.

Furthermore, the corrosion and incorporation of Secondary Phase Particles (SPPs) in to this oxide layer in Zircaloy-4 material has been investigated. In particular, we have focused on mapping the corrosion of Zr2Fe and Zr(Cr,Fe)2 precipitates during the oxidation process, depicting their morphology as the oxidation front advances through the material.

This nanoanalytical approach reveals the true complexity of the oxidation of Zircaloy-4 – an understanding of which will be necessary for the development of sophisticated models of their influence on oxidation behaviour.