Speaker
Description
The polarized positron source of the International Linear Collider requires efficient optical matching of the highly divergent positron beam produced at the target.
The long ILC bunch train also places strong requirements on the stability and operation of the matching device.
This contribution will summarize studies of two alternative concepts: a pulsed solenoid and an active plasma lens.
A pulsed solenoid was studied using numerical optimization and magnetic-field measurements. A simulation framework coupling COMSOL and
ASTRA was used to optimize the solenoid geometry and study positron capture. The simulations identified a transverse dipole kick as an important limitation of the current design,
while measurements of a prototype showed promising temporal field stability.
As a novel alternative, a downscaled active plasma lens prototype was experimentally studied with a focus on discharge stability and long-term operation.
The measurements showed significant electrode erosion and material deposition, changes in discharge behavior over time
and limitations for repetitive MHz operation. High-speed imaging was used to further investigate the spatial and temporal behavior of the plasma discharge.
The results provide a comparison of both concepts and identify the main challenges for their application at the ILC.