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Low voltage transmission EELS

Information about this topic can only be read in German language. Details are also described in our publications about low voltage EELS.

 

This topic has become of international interest. Consequently a Special Issue "Low Voltage Electron Microscopy" in the journal Ultramicroscopy is published in 2014. Prof. Ute Kaiser from Uni Ulm (SLAVE Projekt) and Priv.-Doz. Michael Stöger-Pollach have been invited to act as guest editors.

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Low Voltage TEM - global research activities

Electron Microscopes have a very high spatial resolution compared to optical microscopes and enable elemental mapping by combination of electron energy loss spectrometry (EELS). However, there was almost no successful example of high resolution elemental mapping of biological molecules, which can be easily damaged by the electron beam. This is because biological molecules are damaged by the electron beam before their observation due to the high accelerating voltage, which is 200kV or higher normally.

The actual research challenged to develop a new technology which can reduce electron beam damage by setting the accelerating voltage remarkably lower than the usual (20 to 60kV) and achieve 0.1 nanometer (nm) resolution. In contrast to the other research labs, USTEM sets its focus on the impact of the low beam energies on EELS.

Nion Corp.

Manufacturer of Abberation correctors and dedicated STEM in Kirkland, Washington, USA.
First 60 kV atom resolved EELS image demonstrated 2010 (Er in Fullerene)

  • Nion UltraSTEM 100: 60 kV, 100 kV
  • Nion UltraSTEM 200: 60 kV, 100 kV, 200 kV

NCEM Berkely: TEAM project

National Center for Electron Microscopy and FEI Company: development of a double Cs corrected (S)TEM for 60 kV to 300 kV. Abberation corrected HRTEM image recorded at 30 kV shown at EMC2008, Aachen, Germany

Uni Ulm, Carl Zeiss, CEOS: SALVE project

Develoopment of a Cs and Cc corrected TEM operational at 20kV to 80 kV including Omega-type energy filter for EFTEM, EELS. First 20 kV HRTEM images demonstrated 2010.

Delong

Manufacturer of Low Voltage Tabletop TEM (LV EM5) operational at 5 kV located in Brno, Czech Republic.
Operation modes: TEM, ED, STEM, SEM

Japanes Science and Technology Agency, Tokyo

Development of a double Cs corrected (S)TEM operational from 30 kV to 60 kV.
First 60 kV atom resolved EELS image demonstrated 2009 (Ca, La, Er in Fullerene)
30 kV HRTEM/STEM images demonstrated in 2010.
15 kV HRTEM/HRSTEM images demonstrated in 2013.

USTEM

Fundamental research on EELS, VEELS, EMCD.
First EELS spectrum recorded with 20 keV electrons in May 2008.
First EELS spectrum recorded with 17 keV electrons in July 2010.
First EELS spectrum recorded with 13 keV electrons in March 2012.
First EELS spectrum recorded with 6 keV electrons in October 2012.

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Publications

Publications in peer-reviewed journals:

  1. About the determination of optical properties using fast electrons
    M. Stöger-Pollach
    EMC 2008, Vol.2 (2008) 97

  2. Advantages of Low Beam Energies in a TEM for Valence EELS
    M. Stöger-Pollach, P. Pongratz
    Journal of Physics: Conf. Ser. 209 (2010) 012031 1-4

  3. A new approach in valence EELS: using slow electrons for optical characterization
    M. Stöger-Pollach
    MC 2009, Vol.1 (2009) 113

  4. Low voltage TEM: influences on electron energy loss spectrometry experiments
    M. Stöger-Pollach
    Micron, 41 (2010), 577-584

Invited talks:

  1. The dielectric function obtained with high spatial resolution
    M. Stöger-Pollach and P. Schattschneider
    60th IUVSTA workshop: "Low Energy Spectroscopy and Simulation"    , Vienna, Austria, 11th-13th Nov. 2009

  2. Low beam energies in EELS and EFTEM
    M. Stöger-Pollach, P. Schattschneider, U. Kaiser, J. Biskupek and G. Benner
    7th     workshop on EELS/EFTEM, Zürich, Switzerland, 27th-29th Oct. 2010

  3. Low Losses in EELS for the determination of optical properties of nano-scaled objects using electrons with non-relativistic speed
    M. Stöger-Pollach,
    Physikalisches Kolloquium der TU Graz    , Graz, Austria, 9th November 2010

  4. Transmission elektron microscopy at 20 kV for imaging and spectroscopy: status and future prospects
    U. Kaiser, J. Biskupek, J.C. Meyer, J. Leschner, J. Lechner, Z. Lee, S. Gurasch, U. Goller-Schindler, M. Kinjanyui, H. Rose, M. Stöger-Pollach, A.N. Khlobystov, M. Haider, P. Hartel, H. Müller, S. Eyhusen, G. Benner
    Frühjahrstagung der DPG 2011, Dresden, Deutschland; 13.3.2011 - 18.3.2011

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Literature

Sorry, there is no foreign literature about low voltage VEELS!

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Links

SALVE Project, Prof. Ute Kaiser, Uni Ulm