Sixtrack Simulation of Off-Momentum Cleaning in the LHC

In the LHC, high-amplitude particles are cleaned by ei- ther betatron collimators or momentum collimators. Previously, betatron losses have been studied more in detail since considered as a possible performance limitation of the machine. Measurements during the first years of operation show high losses also in the off-momentum cleaning insertion. This causes a significant radiation dose to warm magnets downstream of the collimators. Our work in this paper aims at simulating with SixTrack the off-momentum particles, driven into the momentum collimators by radiation damping outside the RF system acceptance. The re- sults are an important ingredient in assessing the effective- ness of new passive absorbers to protect the warm magnets.