Beam dynamics simulations of the LANSCE linac

Detailed beam dynamics calculations of the LANSCE Linac have been performed using multi-particle simulation codes. The LANSCE accelerator produces both H{sup +} and H{sup {minus}} beams and is comprised of Cockcroft-Walton injectors, a 100 MeV drift-tube linac and an 800 MeV side-coupled linac. Several improvements to the simulations of H{sup +} and H{sup {minus}} beams have recently been made. These include the use of more accurate input distributions and a better estimate of beam neutralization in the low-energy beam transport. Better estimates of the accelerating fields in the drift-tube linac have also been determined through measurements and modeling. With these improvements better agreement has been achieved between the predictions and measurements of RMS beam parameters and beam losses for both beams. The details of the simulations along with predictions are presented in comparison with measurements for both H{sup +} and H{sup {minus}} beams.