A Study of the Impact of Muons from the Beam Delivery System on the SiD Performance

To suppress the muon background arising from the Beam Delivery System (BDS) of the International Linear Collider (ILC), and to hinder it from reaching the interaction region, two different shielding scenarios are under discussion: five cylindrical muon spoilers with or without an additional magnetized shielding wall. Due to cost and safety issues, the scenario preferred by the Machine-Detector-Interface (MDI) group is to omit the shielding wall, although omitting it also has disadvantages. To support the decision making for the muon shielding, the impact of the muons from the two different shielding scenarios was studied in a full Geant4 detector simulation of the SiD detector, one of two proposed detectors for the ILC. Input to this study is the muon background created by the beam traveling through the BDS, which was simulated with MUCARLO.