A program to determine the radiation spectra due to a single atomic-subshell ionisation by a particle or due to deexcitation or decay of radionuclides Original Research Article

The computer program IMRDEC has been developed to determine the radiation spectra due to a single atomic-subshell ionisation of a stable atom by a particle, or due to the atomic deexcitation or decay of nuclides. The data needed to describe the deexcitation or decay scheme of the mother atoms are obtained from the Evaluated Nuclear Structure Data File (ENSDF) maintained at Brookhaven National Laboratory; this results in the simplest possible input specification. The atomic data as well as the atomic relaxation probabilities are taken from the Evaluated Atomic Data Library (EADL) from Lawrence Livermore National Laboratory. The program IMRDEC calculates the radiation spectra (inclusive the atomic relaxation cascades) optionally, using the deterministic or the Monte Carlo method. The deterministic method results in a much shorter calculation time per nuclide. Due to the many assumptions that worldwide still have to be made in determining the atomic relaxation probabilities as well as in calculating the atomic relaxation, the deterministic method seems to be a small source of inaccuracy.