CERN Accelerating science

Published Articles
Title	Optimization of the secondary electron yield of laser-structured copper surfaces at room and cryogenic temperature
Author(s)	Calatroni, Sergio (CERN) ; Garcia-Tabares Valdivieso, Elisa (CERN) ; Perez Fontenla, Ana Teresa (CERN) ; Taborelli, Mauro (CERN) ; Neupert, Holger (CERN) ; Himmerlich, Marcel (CERN) ; Chiggiato, Paolo (CERN) ; Bajek, David (Dundee U.) ; Wackerow, Stefan (Dundee U.) ; Abdolvand, Amin (Dundee U.)
Publication	2020
Number of pages	10
In:	Phys. Rev. Accel. Beams 23 (2020) 033101
DOI	10.1103/PhysRevAccelBeams.23.033101
Subject category	Accelerators and Storage Rings
Project	CERN HL-LHC
Abstract	Electron cloud (e-cloud) mitigation is an essential requirement for proton circular accelerators in order to guarantee beam stability at a high intensity and limit the heat load on cryogenic sections. Laser-engineered surface structuring is considered a credible process to reduce the secondary electron yield (SEY) of the surfaces facing the beam, thus suppressing the e-cloud phenomenon within the high luminosity upgrade of the LHC collider at CERN (HL-LHC). In this study, the SEY of Cu samples with different oxidation states, obtained either through laser treatment in air or in different gas atmospheres or via thermal annealing, has been measured at room and cryogenic temperatures and correlated with the surface composition measured by x-ray photoelectron spectroscopy. It was observed that samples treated in nitrogen display the lowest and more stable SEY values, correlated with the lower surface oxidation. In addition, the surface oxide layer of air-treated samples charges upon electron exposure at a low temperature, leading to fluctuations in the SEY.
Copyright/License	publication: © 2020-2025 authors (License: CC-BY-4.0)

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