Development of Collimation Simulations for the FCC-ee

A collimation system is under study for the FCC-ee to protect the machine from the multi-MJ electron and positron beams and limit the backgrounds to the detectors. One of the key aspects of the collimation system design is the setup of simulation studies combining particle tracking and scattering in the collimators. The tracking must include effects important for electron beam single-particle dynamics in the FCC-ee, such as synchrotron radiation. For collimation, an aperture model and particle-matter interactions for electrons are required. There are currently no established simulation frameworks that include all the required features. The latest developments of an integrated framework for multi-turn collimation studies in the FCC-ee are presented. The framework is based on an interface between tracking codes, pyAT and Xtrack, and a particle-matter interaction code, BDSIM, based on Geant4. Promising alternative simulation codes and frameworks are also discussed. The challenges are outlined, and the first results are presented, including preliminary loss maps for the FCC-ee.