R&D for Positron Sources at High-Energy Lepton Colliders

TL;DR

This paper reviews the development of positron sources for high-energy lepton colliders like ILC, CLIC, and HALHF, focusing on undulator-based sources, target testing, and innovative plasma lens technology.

Contribution

It provides an overview of the current positron source designs, including new technological developments such as plasma lenses for optics matching.

Findings

Successful target tests for positron production

Design insights for rotating target wheels

Development of plasma lens technology

Abstract

Several designs for high-energy Lepton Colliders serving as Higgs factories but extendable to higher energies up to the TeV range are under discussion. The most mature design is the International Linear Collider (ILC), but also the Compact Linear Collider (CLIC) as well as the new concept of a Hybrid Asymmetric Linear Higgs Factory (HALHF) have a large physics potential. The first energy stage with $\sqrt{s}=250$~GeV requires high luminosity and polarized beams and imposes an effort for all positron source designs at high-energy colliders. In the baseline design of the ILC, an undulator-based source is foreseen for the positron source in order to match the physics requirements. In this contribution an overview is given about the undulator-based source, the target tests, the rotating target wheel design, as well as the pulsed solenoid and the new technology development of plasma lenses as optic matching devices.