Proceedings of the 1999 Particle Accelerator Conference
The pressure history in the components of an rf linac has been modeled using Mathematica. Specifically the Cavity Coupled Drift Tube Linac (CCDTL) and the Cavity Coupled Linac (CCL) sections of the Accelerator Production of Tritium (APT) plant have been modeled in order to predict the optimal pump configuration over the 224 meter length. The pressure history in up to 43 sub-volumes within three representative modules (about three meters long) is analyzed in detail. Included in our model are time-dependent outgassing rates and pressure-dependent pump speeds. With this information, we solve for the pressure history during roughing and with turbo and ion pumps. The number and size of each pump is optimized to achieve the desired pressure with minimal costs.