Suppression of muon backgrounds generated in the ILC beam delivery system

Muon background suppression at the ILC collider detectors was studied by MARS 15 Monte Carlo simulation with a detailed description of the ILC BDS beam line and tunnel of 1.6-km length. Muon suppressions of about 1/5 and 1/50 were obtained for the donut- and wall-shape muon-spoilers, respectively.