An anti-Compton suppression Ge-telescope detection system for quality control of nuclear waste packages

An anti-Compton suppression system is studied for the quality control of radioactive waste packages by nondestructive assay. The main objective is the reduction of the detection limit of actinides in the packages. The optimization of a final device is based on Monte Carlo simulations (MCNP and FLUKA) validated by experiments using a prototype consisting of a Ge-telescope detector surrounded by a NaI detector. The validation reveals that most of the discrepancies between experimental and simulated data are due to an incomplete description of the experimental conditions. After fine-tuning of the input file the uncertainties on the simulated full-energy peak efficiency are reduced to less than 5%. Also the total detector response for mono-energetic photons and real waste, including the photon interactions within the drum, can be simulated satisfactorily.