CERN Accelerating science

Internal Note
Report number	CERN-ACC-NOTE-2023-0019
Title	Machine Protection and Availability in the FCC-ee
Abbreviation	FCC-ee: Future Circular Lepton Collider
Author(s)	Heron, Jack (CERN) ; Felsberger, Lukas (CERN) ; Hernalsteens, Cedric (CERN) ; Wiesner, Christoph (CERN) ; Wollmann, Daniel (CERN) ; Uythoven, Jan (CERN) ; Rodriguez Mateos, Felix (CERN)
Corporate author(s)	CERN. Geneva. ATS Department
Publication	2023
Imprint	13 Nov 2023
Number of pages	19
Subject category	Engineering ; Accelerators and Storage Rings
Study	CERN FCC
Keywords	Machine Protection ; Availability ; Down Time ; Reliability ; Repair ; Maintenance ; Future Circular Collider ; FCC ; FCC-ee
Abstract	The FCC-ee will combine high stored beam energy with small vertical emittance. The loss of only a small part of the beam into accelerator equipment, collimators or passive absorbers could be extremely destructive. Therefore, a highly reliable machine protection system is required for the entire accelerator chain. Further, the FCC-ee schedule has 185 days allocated to physics each year, of which a minimum percent must be spent at nominal parameters if integrated luminosity goals are to be reached. Machine protection and availability are vital considerations from the outset of the design stage. This paper presents the current status and outlook for both topics relating to analysis, research and development (R&D;). First, relevant topics in machine protection are discussed. Fault mechanisms are treated as well as key considerations such as minimum reaction time, beam loss detection, dust interaction, fast failures and quench protection. Next, availability assurance is considered. Three steps are proposed: (I) Coarsely define system availability targets scaled to the complexity of delivery. (II) Establish the projected availability based on existing designs and similar systems. (III) If the latter is insufficient, study how this can be improved.
Submitted by	[email protected]