In conventional LEIS, secondary ions, generated by the impact of the noble gas ions, lead to a high background for low scattering energies.
This background reduces dynamic range and detection limits, in particular for light elements.
The Qtac is equipped with a time-of-flight detection system, which separates the scattered noble gas ions from this background. This unique feature significantly improves the elemental detection limits and the dynamic range of the instrument.
LEIS spectrum of a technical polymer without time-of-flight mass filtering
LEIS spectrum of the same sample with time-of-flight mass filtering showing significantly improved detection limits