Beam Delivery System-Collimators

A realistic front-end STRUCT-MARS15-GEANT4 model of the Beam Delivery System (BDS), interaction region and extraction beam line has been created and tested for 2 and 20-mrad crossing angles, and partially for a 14-mrad crossing angle. The model based on the corresponding layouts, includes all the beam elements in that region with their detailed 3D geometry, materials and magnetic field distributions, collimators and masks, tunnel and the SID collider detector. Detailed simulations have been performed on effects of synchrotron radiation with respect to performance of collimation and extraction systems and on radiation loads to the BDS and extraction components. Simulations and benchmarking of results on collimation system performance are done with the BDSIM, MARS15 and STRUCT codes (EPAC paper). Comprehensive modeling of BDS-induced backgrounds in the SiD detector with respect to those generated in collisions has been performed for various configurations of the tunnel magnetic spoilers and different time windows of all the SiD sub-detectors. For the new model, Fermilab scientists will conduct calculation studies of machine-induced backgrounds in the SiD detector in comparison with those from the interaction point.