Set Energy Range

The spectrometer can be set to give a variable energy range depending on the experimental requirements. To change the energy range:

  1. Set the energy range using the Dispersion setting that you can access via the (...) option in the control region of the Microscope System palette.

    1. Use a small eV/ch setting (large dispersion) for detailed spectra around an edge or the ZLP.

    2. Use a large eV/ch setting (small dispersion) microanalysis or mapping.

  2. Set energy rangeIf the exposure is set to Auto, the exposure time will automatically adjust as the energy loss changes. This is very useful when going from a high to low energy offset. The auto feature will predict the large increase in intensity and adjust accordingly.

Related content

Related FAQ's

  • Which dispersion should I use?

    This depends on the type of experiment. For chemical mapping fine structure analysis, a higher energy resolution is required. Therefore higher dispersions (smaller eV/channel numbers) are required.

    For compositional analysis, only lower dispersions (big numbers) are suited. In general for compositional analysis and fast mapping, a dispersion of 1 eV/ch seems to be optimal because it gives the biggest field of view (2000 eV in the GIF Quantum® system) and the highest intensity on the CCD and EELS.

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  • My map and/or images are noisy. What can I do?

    Make sure the sample is thin by acquiring a relative thickness map. If it is thick (e.g., relative thickness >1), try moving to another sample area. Increase the number of collected electrons by one (or all) of the following:

    • Increase the beam intensity
    • Increase the camera exposure
    • Increase the CCD binning
    • Increase the slit width
    • Increase the number of frames summed
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  • Why is my spectrum noisy?

    More signal is needed. Use a larger spectrometer aperture, increase vertical binning, have a longer exposure or higher beam current (provided the sample can stand the electron beam).

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