Predicting the radiation environment at high-luminosity hadron-collider experiments

The physics requirements of future hadron-collider experiments require very high collision rates, leading to harsh radiation environments never before confronted in large-scale high-energy physics experiments. The high levels of radiation backgrounds becomes a major design criterion for such experiments. Considering the enormous cost and effort involved in building modern high-energy physics experiments, it is vital that particle fluences and energy depositions can be predicted reliably. This is done using Monte-Carlo simulation programs. Given in this paper are the results of comparisons in which the predictions of different simulation programs, all used in the evaluation of radiation backgrounds in the ATLAS and CMS experiments at the CERN Large Hadron Collider, are analysed. Such comparisons give confidence when the predictions agree, and possible cause for further investigation when they disagree.