Measurement of the phase contrast transfer function and the cross-correlation peak using young interference fringes

Abstract

Cross-correlation of micrographs taken under identical optical conditions allows measurement of (a) the optical transfer function free from electron and photographic noise and (b) object change, especially that due to radiation damage. Light optical methods based on superposition diffractograms are discussed. A subtraction procedure is described for measuring the optical transfer function, and a two-step diffraction process is presented for measuring object change. As an example, experiments with radiation damage in carbon foil are described. Here increased stability regarding radiation-induced change was found with increasing dose, making possible measurement of deviations from the “zero dose image”.