Speaker
Description
To achieve high luminosity in the International Linear Collider (ILC), we need a high-current multi-bunch beam. Maximizing the positron capture efficiency (yield) is a key challenge. Positrons go through capture and booster linacs before entering the damping ring. For good transport efficiency later, it is important not only to get many positrons, but also to make the bunch short during the capture stage. In this study, we simulated the beam behavior in the capture section of the ILC electron-driven positron source. This section includes a target, a flux concentrator (FC), a collimator, and solenoid-focused accelerating structures. Previous studies showed that beam loss at the collimator is the biggest issue, and the bunch length is mostly decided around the fourth accelerating structure. Based on this, we investigated how the component layout and magnetic field in the upstream region of the capture linac affect the yield and bunch length. We investigated the parameter dependencies to provide guidelines for efficient beam capture under realistic engineering constraints. In this presentation, we report these simulation results.