Two thickness measurement methods using an electron energy loss spectroscopy (EELS) and 10a convergent beam

electron diffraction (CBED) were compared in an Fe-18Mn-0.7C alloy. The thin foil specimen was firstly tilted to

satisfy 10a two-beam condition. Low loss spectra of EELS and CBED patterns were acquired in scanning

transmission electron microscopy (STEM) and TEM-CBED modes under the two-beam condition. The log-ratio

method was used for measuring the thin foil thickness. Kossel-Möllenstedt (K-M) fringe of the 131 diffracted disk of

austenite was analyzed to evaluate the thickness. The results prove the good coherency between both methods in

the thickness range of 72 ~ 113 nm with a difference of less than 5%.

Keywords: Thickness measurement, EELS, CBED, TEM, Carbon contamination method​