To measure the IMFP, one well known method is elastic-peak electron spectroscopy (EPES). This method measures the intensity of elastically backscattered electrons with a certain energy from a sample material in a certain direction. Applying a similar technique to materials whose IMFP is known, the measurements are compared with the results from the Monte Carlo simulations under the same conditions. Thus, one obtains the IMFP of a certain material in a certain energy spectrum. EPES measurements show a root-mean-square (RMS) difference between 12% and 17% from the theoretical expected values. Calculated and experimental results show higher agreement for higher energies.
For electron energies in the range 30 keV – 1 MeV, IMFP can be directly measured by electron energy loss spectroscopy inside a transmission electron microscope, provided the sample thickness is known. Such measurements reveal that IMFP in elemental solids is not a smooth, but an oscillatory function of the atomic number.
For energies below 100 eV, IMFP can be evaluated in high-energy secondary electron yield (SEY) experiments. Therefore, the SEY for an arbitrary incident energy between 0.1 keV-10 keV is analyzed. According to these experiments, a Monte Carlo model can be used to simulate the SEYs and determine the IMFP below 100 eV.