Conceptual design of a beam line for post-collision extraction and diagnostics at the multi-TeV Compact Linear Collider

Abstract

Strong beam-beam effects at the interaction point of a high-energy ${e}^{+}{e}^{\ensuremath{-}}$ linear collider such as the Compact Linear Collider (CLIC) lead to an emittance growth for the outgoing beams, as well as to the production of beamstrahlung photons and ${e}^{+}{e}^{\ensuremath{-}}$ coherent pairs. In this paper, we present a conceptual design of a 150 m long post-collision extraction line for the CLIC machine at 3 TeV, which separates the various components of the outgoing beam using a vertical magnetic chicane, before transporting them to their respective dump. In addition, detailed studies are performed in order to compute the power losses along the CLIC post-collision line. For the vacuum window at the exit of the post-collision line, we propose a thick (1.5 cm) layer of carbon-carbon composite, with a thin (0.2 mm) aluminum leak-tight foil. The stress levels in this exit window are estimated. Finally, we discuss the use of diagnostics along the post-collision line for monitoring and improving the quality of the ${e}^{+}{e}^{\ensuremath{-}}$ collisions and, in turn, the luminosity of the CLIC machine.