Liquid Xenon Positron Target

Positron targets are a critical component of future linear colliders. Traditional targets are composed of high-Z metals that become brittle over time due to constant bombardment by high-power electron beams. We explore the possibility of a liquid xenon (LXe) target which is constantly refreshed and therefore not susceptible to the damage mechanisms of traditional solid targets. Using GEANT4 simulation code, we examine the performance of the liquid xenon target and show that the positron yield and divergence are comparable to solid targets when normalizing by radiation length. Additionally, we observe that the peak energy deposit density (PEDD) threshold for LXe is higher than for common solid targets, which makes it an attractive positron target alternative. We develop parameter sets for a demonstration application at FACET-II, ILC, C$^3$, and for an ideal linear accelerator designed around the LXe target.