Extending estimating hydrogen content in atom probe tomography experiments where H2 molecule formation occurs

Journal article

We investigate a new method for estimating specimen hydrogen content in Atom Probe Tomography (APT) in experiments where molecular hydrogen ions (𝐻2 +) originating from the measurement environment can overlap with deuterium (𝐷 +) in the mass-to-charge-state spectrum, thus preventing direct application of isotopic marking for unambiguous hydrogen analysis. First, we apply an existing method for hydrogen content estimation, using 𝐻 +/ 𝐻2 + ratios obtained from paired deuterated/non-deuterated experiments, demonstrating sufficient residual uncertainty to motivate exploring an alternative method to accurately estimate hydrogen content. By varying the time between evaporation events, it is then shown that a highly correlated relationship between field evaporation rate and hydrogen content can also be used to predict hydrogen content. This leads to a new method for measuring hydrogen content within the specimen. We combine this extrapolation technique with continuous cycling of the evaporation rate or pulse frequency during an APT experiment. This could enable spatially resolved imaging of hydrogen concentrations despite the presence of a contaminant background hydrogen signal, without the need for deuteration.

Authors: Meier, MS; Jones, ME; Felfer, PJ; Moody, MP; Haley, D

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Cambridge University Press
• Journal: Microscopy and Microanalysis
• Volume: 28
• Issue: 4
• Pages: 1231-1244
• Publication date: 2021-07-28
• Acceptance date: 2021-07-01
• DOI: 10.1017/S1431927621012332
• EISSN: 1435-8115
• ISSN: 1431-9276
• Language: English
• Keywords: FFR