Method and program for decay scheme reconstruction based on formal logical analysis of gamma-gamma coincidence matrix

A new, rigorously substantiated approach to construction of decay schemes on the basis of γ-γ coincidence data is described. Complete decay modes (concrete cascades of transition from excited to the ground state of a nucleus excited in a decay or a reaction) and continuity regions in complete modes (regions of successive transitions) are isolated by logical operations with rows (columns) of a symmetrical coincidence matrix where rows (columns) correspond to energies of coinciding transitions and matrix elements are unities and zeros, depending on the presence or absence of the given coincidence. To reject false complete modes and continuity regions arising from incompleteness of the coincidence data and errors in them, energy selection is introduced for complete modes and continuity regions. This requires that the total energy of their constituent transitions should be equal to the total energy of some other complete modes and continuity regions and to the energies of singles. With the continuity regions found, it is possible to order transitions in the selected complete modes and to algorithmize matching of complete modes into a decay scheme.