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. NovelliPrimo
;
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.File | Dimensione | Formato | |
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