Mössbauer Imaging

In a Mössbauer experiment, if a spatially-extended absorbing sample is rotated relative to a moving γ-ray source, lines of constant γ-ray Doppler shift are generated through the absorber parallel to the motion of the source. As a result, resonant absorption takes place along a series of parallel lines cutting through the absorber, where a particular line is determined by the velocity of the source. The result is a series of measurements of line integrals of the absorption coefficient through the absorber. An image or spatial map of the absorption coefficient distribution may then be reconstructed using tomographic image-reconstruction algorithms. Moreover, when measurements are recorded both as a function of the source velocity and the absorber rotational velocity, spectral information may also be recovered as a function of position. Spatial resolution is proportional to the rate of rotation of the absorber, but is ultimately signal-to-noise limited.