Conversion‐electron Mössbauer spectroscopy of thin films

Mössbauer spectra of thin, unenriched Fe and Fe–Si films were obtained from conversion electrons in a backscatter geometry. The electron detector was a windowless, channel electron multiplier constructed in our laboratory. It operates in vacuum with a relatively high efficiency for counting electrons, enabling the measurement of spectra from thin films deposited on conventional, thick substrates and eliminates the necessity for thin transparent absorbers. A comparison between common transmission Mössbauer spectroscopy and the more rarely employed backscatter methods shows that backscatter conversion‐electron Mössbauer spectrscopy results in larger signal‐to‐noise ratios as well as significant reduction in counting times when thin films are involved. The magnitude of the effects theoretically expected in films will be discussed and compared with that measured experimentally.