The effects of pump-down to straw stations in the SHiP decay volume

This note investigates the hypothetical negative effects of a pump-down process to tracker stations within the SHiP spectrometer vessel due to restricted airflow and pressure differences. By considering a proposed tracker station design that reflects the ’worst case’ scenario, both an analytical and a CFD model (using ANSYS Fluent) are presented. Simplified assumptions within the analytical model favour the computational model’s results. This model predicts that for a given 10 cm gap, the forces upon the tracker station would be < 100 N and have pressure differences < 1 Pa.