MODGAN: An efficient Monte Carlo code for long chains of evaporative emission

The evaporation code MODGAN has been developed to follow ejectile kinematics and complex decay chains from highly excited nuclei. It allows calculations of multiplicity, energy and angular distributions of particles ejected from hot, high spin composite nuclei. By using analytical expressions and expansions where necessary, the code has been made very efficient. Good agreement is found in comparisons of results between MODGAN and the code LILITA-N90. For the calculation of particle energy spectra at specific lab angles, an enormous increase in efficiency has been achieved in MODGAN over conventional methods. This is achieved through forced alterations of particle directions from those that were originally unrestricted, coupled to corrections by use of appropriate weights for binning. This method is particularly advantageous when considering coincidence measurements between detectors of small solid angle.