Measurements and modelling of stray magnetic fields and the simulation of their impact on the Compact Linear Collider at 380 GeV

TL;DR

This paper investigates the effects of stray magnetic fields on the performance of the Compact Linear Collider at 380 GeV, using measurements, modeling, and simulations to assess their impact on luminosity.

Contribution

It introduces a statistical model of stray magnetic fields based on measurements and integrates it into CLIC simulations to evaluate luminosity degradation.

Findings

Stray magnetic fields can significantly affect beam alignment and emittance.

Mitigation systems can reduce the impact of stray magnetic fields.

Simulations show the importance of accounting for stray fields in collider design.

Abstract

The Compact Linear Collider (CLIC) targets a nanometre beam size at the collision point. Realising this beam size requires the generation and transport of ultra-low emittance beams. Dynamic imperfections can deflect the colliding beams, leading to a collision with a relative offset. They can also degrade the emittance of each beam. Both of these effects can significantly impact the luminosity of CLIC. In this paper, we examine a newly considered dynamic imperfection: stray magnetic fields. Measurements of stray magnetic fields in the Large Hadron Collider tunnel are presented and used to develop a statistical model that can be used to realistically generate stray magnetic fields in simulations. The model is used in integrated simulations of CLIC at 380GeV including mitigation systems for stray magnetic fields to evaluate their impact on luminosity.