Soft X-ray spectra of boron and carbon excited by 10 to 40 MeV C, N and O ions

Spectra taken with a lead stearate pseudocrystal show no evidence for the KL satellite of boron at 191 eV or the KL3 satellite of carbon, and very weak emission in the carbon KL2 satellite at 287 eV. Experimental details and two possible interpretations are presented. L vacancies may be filled before X-ray emission, thereby decreasing satellite fluorescence yield. This may be the case in boron, where the response time of the electron gas is much smaller than the lifetime of the boron ion with a K vacancy, while in carbon these times are comparable. The possibility that the fast ions produce mostly K ionisation cannot be ruled out by the experiment.