Reduction of secondary electron yield for E-cloud mitigation by laser ablation surface engineering

R. Valizadeh, O. B. Malyshev, S. Wang, Bhagat-Taaj Sian, M. D. Cropper, N. Sykes

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Developing a surface with low Secondary Electron Yield (SEY) is one of the main ways of mitigating electron cloud and beam-induced electron multipacting in high-energy charged particle accelerators. In our previous publications, a low SEY < 0.9 for as-received metal surfaces modified by a nanosecond pulsed laser was reported. In this paper, the SEY of laser-treated blackened copper has been investigated as a function of different laser irradiation parameters. We explore and study the influence of micro- and nano-structures induced by laser surface treatment in air of copper samples as a function of various laser irradiation parameters such as peak power, laser wavelength (λ = 355 nm and 1064 nm), number of pulses per point (scan speed and repetition rate) and fluence, on the SEY. The surface chemical composition was determined by x-ray photoelectron spectroscopy (XPS) which revealed that heating resulted in diffusion of oxygen into the bulk and induced the transformation of CuO to sub-stoichiometric oxide. The surface topography was examined with high resolution scanning electron microscopy (HRSEM) which showed that the laser-treated surfaces are dominated by microstructure grooves and nanostructure features.

    Original languageEnglish
    Pages (from-to)370-379
    Number of pages10
    JournalApplied Surface Science
    Volume404
    Early online date4 Feb 2017
    DOIs
    Publication statusPublished - 15 May 2017

    Keywords

    • Electron cloud
    • Electron multipacting
    • Laser ablation
    • Laser surface engineering
    • Particle accelerators
    • Secondary electron yield (SEY,)

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