Depolarization in the ILC Linac-to-Ring Positron Beamline

TL;DR

This paper investigates the depolarization effects on polarized positron beams in the ILC linac-to-ring transfer line, emphasizing the importance of spin tracking to preserve polarization for future collider experiments.

Contribution

It presents the results of positron spin tracking and depolarization analysis at the PLTR beamline, providing insights into polarization preservation during beam transport.

Findings

Depolarization effects are significant in the linac-to-ring transfer line.

Spin tracking results help optimize beamline components to maintain polarization.

The study informs design improvements for future linear colliders.

Abstract

To achieve the physics goals of future Linear Colliders, it is important that electron and positron beams are polarized. The positron source planned for the International Linear Collider (ILC) is based on a helical undulator system and can deliver a polarised beam with positron polarization of 60%. To ensure that no significant polarization is lost during the transport of the electron and positron beams from the source to the interaction region, spin tracking has to be included in all transport elements which can contribute to a loss of polarization. These are the positron source, the damping ring, the spin rotators, the main linac and the beam delivery system. In particular, the dynamics of the polarized positron beam is required to be investigated. The results of positron spin tracking and depolarization study at the Positron-Linac-To-Ring (PLTR) beamline are presented.