Reduction of multiple hits in atom probe tomography
Artikel i vetenskaplig tidskrift, 2013

The accuracy of compositional measurements using atom probe tomography is often reduced because some ions are not recorded when several ions hit the detector in close proximity to each other and within a very short time span. In some cases, for example in analysis of carbides, the multiple hits result in a preferential loss of certain elements, namely those elements that frequently field evaporate in bursts or as dissociating molecules. In this paper a method of reducing the effect of multiple hits is explored. A fine metal grid was mounted a few millimeters behind the local electrode, effectively functioning as a filter. This resulted in a decrease in the overall detection efficiency, from 37% to about 5%, but also in a decrease in the fraction of multiple hits. In an analysis of tungsten carbide the fraction of ions originating from multiple hits decreased from 46% to 10%. As a result, the measured carbon concentration increased from 48.2 at%to 49.8 at%, very close to the expected 50.0 at%. The character- istics of the multiple hits were compared for analyses with and without the grid filter.

Carbides

Multiple hits

Quantification

Atom probe tomography

Tungsten carbide

Detection efficiency

Författare

Mattias Thuvander

Chalmers, Teknisk fysik, Materialens mikrostruktur

Anders Kvist

Chalmers, Teknisk fysik, Materialens mikrostruktur

Lars J S Johnson

Linköpings universitet

Jonathan Weidow

Chalmers, Teknisk fysik, Materialens mikrostruktur

Hans-Olof Andrén

Chalmers, Teknisk fysik, Materialens mikrostruktur

Ultramicroscopy

0304-3991 (ISSN)

Vol. 132 81-85

Ämneskategorier

Analytisk kemi

Styrkeområden

Materialvetenskap

DOI

10.1016/j.ultramic.2012.12.005