Statefit: A Computer Program to Facilitate Interpretation of Spectroscopic Data

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STATEFIT is a program written in Fortran IV for the IBM 370/195 computer to facilitate the interpretation of spectroscopic data. A list containing all the experimentally determined ..gamma..-ray energies, their relative intensities, the uncertainties in each, and when known, the total internal conversion coefficients is supplied as input. A preliminary partial decay scheme is assumed to already exist, and a second list specifying those ..gamma.. rays representing transitions between members of this group of energy levels is also provided as input data. Before execution is allowed to proceed, the two lists are subjected to ten different tests to locate possible user errors and if any are found, they are noted. Identification of a fatal error such as the inadvertent assignment of two different gamma rays between one pair of states, causes termination. The energies of the presumed states are not estimated, but are treated as varible parameters. For purposes of the calculation, each state is identified by an arbitrary index number. The best energy values of the states are determined by making a least-squares fit of the level energies to the network of assigned gamma rays. Transition intensities R/sub T/ = R/sub r/ (1 + a) are calculated, and for radioactive samples the fractional beta feeding to each state is computed. A table of all possible transitions between the calculated states is then computed and listed in monotonically increasing order. The complete list of experimentally observed gamma rays is then searched for additional acceptable assignments. The acceptance criterion for selection of such possible additional assignments is externally adjustable. Space required for 20 excited states, 50 assigned gamma rays and 100 observed gamma rays is 15C60/sub 16/(89,184/sub 10/) bytes. Space required for 120 excited states, 500 assigned gamma rays and 1200 observed gamma rays is 61A58/sub 16/(399,960/sub 10/) bytes.