Optimisation of control parameters for a particle radiation assembly considering particle count dynamics

The invention relates to a device (68) for determining control parameters for a particle irradiation system, wherein the particle irradiation system different doses at different target points in a target volume (56) for disposal in landfills by driven by a particle beam sampling. The apparatus (68) comprises an input (70) for receiving information concerning a predefined dose distribution over the target points, and a determination component for determining a landfill during irradiation to particle number distribution over sampling points. The determination is made using the predefined dose distribution and a size, take into account the differences of the particle number distribution between particle numbers of different sampling.