Beam Loss Simulation Studies for ALS Top-Off Operation

ALS[1] has been proposing the Top-off injection[2] of the electron beam. As a part of its radiation safety study, we carried out two kinds of tracking studies: (1) to confirm that the injected beam cannot go into users' photon beam lines, and (2) to control the location of the beam dump when the storage ring RF is tripped. (1) is done by tracking electrons from a photon beam line to the injection sector inversely by including the magnetic field profiles, varying the field strength with geometric aperture limits to conclude that it is impossible. (2) is done by tracking an electron with radiation in 6-dim space for different combinations of vertical scrapers for the realistic lattice with errors.