The ability of a low Secondary Electron Yield coatingto mitigate detrimental electron cloud effects potentially af-fecting accelerators’ performances has been convincinglyvalidated. The interference of such coatings with other prop-erties required to accelerator constructive materials (i.e. vac-uum compatibility, magnetic permeability, high surface con-ductivity, etc.) is of great concern and has recently attracted alot of interest and studies. For instance, the severe impedancebudget constraint requires the highest conductivity in thesurface layers within the skin depth (typically someμm)characteristic of the e.m. interaction. It is therefore of ut-termost importance to define the minimum thickness oneoverlayer should have in order to be an effective electroncloud mitigator and minimize its impact to surface conduc-tivity.To this purpose, XPS and Secondary electron spectroscopyhave been simultaneously applied to the prototypical systemformed by increasing coverages of amorphous Carbon (a-C)deposited on atomically clean Cu. XPS has been successfullyused to qualify and quantify the a-C thickness, renderingpossible a detailed coverage dependent study. A significantlythin a-C layer, of about 5 to 7 nm, is surprisingly enoughto lower the secondary emission properties of the wholesystem below 1. This observation opens up the possibilityto develop, on industrial scale, thin enough electron cloudmitigators that will not affect impedance issues.

Surface effects for electron cloud / Novelli, A.; Angelucci, M.; Liedl, A.; Spallino, L.; Cimino, R.; Larciprete, R.. - (2020), pp. 186-189. - CERN YELLOW REPORTS. CONFERENCE PROCEEDINGS. [10.23732/cyrcp-2020-009.186].

Surface effects for electron cloud

A. Novelli
Primo
;
2020

Abstract

The ability of a low Secondary Electron Yield coatingto mitigate detrimental electron cloud effects potentially af-fecting accelerators’ performances has been convincinglyvalidated. The interference of such coatings with other prop-erties required to accelerator constructive materials (i.e. vac-uum compatibility, magnetic permeability, high surface con-ductivity, etc.) is of great concern and has recently attracted alot of interest and studies. For instance, the severe impedancebudget constraint requires the highest conductivity in thesurface layers within the skin depth (typically someμm)characteristic of the e.m. interaction. It is therefore of ut-termost importance to define the minimum thickness oneoverlayer should have in order to be an effective electroncloud mitigator and minimize its impact to surface conduc-tivity.To this purpose, XPS and Secondary electron spectroscopyhave been simultaneously applied to the prototypical systemformed by increasing coverages of amorphous Carbon (a-C)deposited on atomically clean Cu. XPS has been successfullyused to qualify and quantify the a-C thickness, renderingpossible a detailed coverage dependent study. A significantlythin a-C layer, of about 5 to 7 nm, is surprisingly enoughto lower the secondary emission properties of the wholesystem below 1. This observation opens up the possibilityto develop, on industrial scale, thin enough electron cloudmitigators that will not affect impedance issues.
2020
Proceedings of the ICFA mini-Workshop onMitigation of Coherent Beam Instabilities in Particle Accelerators
978-92-9083-589-9
Coatings, Electron Cloud, Secondary Electron Yield, X-ray Electron Emission
02 Pubblicazione su volume::02a Capitolo o Articolo
Surface effects for electron cloud / Novelli, A.; Angelucci, M.; Liedl, A.; Spallino, L.; Cimino, R.; Larciprete, R.. - (2020), pp. 186-189. - CERN YELLOW REPORTS. CONFERENCE PROCEEDINGS. [10.23732/cyrcp-2020-009.186].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1487176
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