BASIC programs to compute source densities from autoradiographic cross-fire matrices

Two different mathematical procedures to compute source densities from cross-fire matrices in quantitative EM autoradiography are reported. BASIC programs for a desk-top microcomputer were written to fit the hypothetical silver grain distribution to the observed real silver grain distribution using a non-iterative linear process (least-squares procedure) and an iterative method, which minimizes the chi-square component between the observed and computed silver grain distributions. The latter procedure uses a Gauss-Newton algorithm.