Potential impedance reduction by REBCO-coated conductors as beam screen coating for the Future Circular Hadron Collider

¹ ALBA Synchrotron Light Source - Carrer de la Llum 2-26, 08290 Cerdanyola del Valles, Barcelona, Spain
² UPC CommSensLab, Department of Signal Theory and Communications, Universitat Politècnica de Catalunya C. Jordi Girona 1, 08034 Barcelona, Spain
³ CERN, Technology Department - Espl. des Particules 1, 1211 Meyrin, Switzerland

^(a) E-mail: patrickkrkotic@outlook.de (corresponding author)

Received: 6 October 2022
Accepted: 12 December 2022

Abstract

The Future Circular Collider study creates a conceptual design for a post-LHC particle accelerator using 16 T superconducting dipoles to achieve collision energies of up to 100 TeV in a 90 km circumference ring. A copper-coated beam screen, similar to that used in the LHC, is planned. However, the undertaken research indicates that copper at the high working temperature of 50 K has a strong influence on the accelerator's performance, particularly at injection energy. In this work, we relate the experimentally determined properties of REBCO-coated conductors with their potential performance in the FCC-hh beam screen. Specifically, we use a round pipe approximation to demonstrate that a beam screen coated with a combination of REBCO and copper can have a much lower resistive wall impedance than one using only copper. The reduction is substantial (several orders of magnitude), and is observed in both the longitudinal and transverse wall impedance. Such a reduction has important effects on beam stability, operating costs, potential reduction in beam screen size, and lowering the stringent specifications of the 16 T magnets required for the Future Circular Hadron Collider.