Impact of Dynamical Stray Fields on CLIC

In this paper we estimate the tolerances of stray-fields variations on the Compact Linear Collider (CLIC), discuss possible sources and propose several solutions. The Beam Delivery System (BDS) is the most sensitive system of CLIC to unwanted magnetic field variations, already variations of 1 nT would reduce the luminosity by 10% at wavelengths comparable to the BDS without considering any correction mechanism. Two sources of magnetic field variations are considered, natural and man-made. Precise magnetic field measurements at Earth's surface under a typical geomagnetic storm are presented. Additionally, stray field measurements have been conducted at CERN, to inspect B-field variations due to technical equipment in an accelerator environment. Different solutions are proposed to minimise the impact of stray fields on the CLIC performance.