Experimental results are presented from an experiment in which ionization created by a high energy X-ray synchrotron radiation beam intersecting an ethylene diffusion flame is measured. The ionization signal is believed to arise from X-ray absorption by aggregated soot particles. Comparisons are made between these ionization profiles and those that are a result of natural flame ionization. Visible light absorption measurements were also performed to determine the soot volume fraction in the beam and the results compared with the X-ray induced signals.