IPAC2014 - List of Authors (Muranaka, T.)

Paper	Title	Page
WEPME005	Enhanced Field Emission and Emitter Activation on Flat Dry-ice Cleaned Cu Samples	2261
	S. Lagotzky, G. Müller, P. Serbun Bergische Universität Wuppertal, Wuppertal, Germany S. Calatroni, T. Muranaka CERN, Geneva, Switzerland
	Enhanced field emission (EFE), resulting in dark currents and electric breakdowns, is one of the main gradient limitations for the CLIC accelerating structures (actual design Eacc = 100 MV/m, Epeak = 240 MV/m ). Measurements on diamond-turned, flat (Ra = 158 nm) Cu samples showed first EFE at surface fields Es = 130 MV/m. In order to reduce EFE, we have installed a commercial dry ice cleaning (DIC) system in a clean room environment (class iso 5). Accordingly, the number density of emitters (N) was significantly decreased by DIC from N = 52 /cm² to N = 12 /cm² at Es = 190 MV/m. Furthermore we have tested two diamond-turned and chemically etched (SLAC treatment, Ra = 150 nm) Cu samples after DIC resulting in EFE onset at 230 MV/m. Locally measured I(V) curves of the strongest emitters yielded field enhancement factors b = 10 – 90 (10 – 85) on the diamond-turned (chemically etched), respectively. SEM and EDX investigations of the located emission sites revealed surface defects and few particulates (Al, Ca, Si) as origin of the EFE. Moreover, strong emitter activation effects were observed. A possible breakdown mechanism based on this EFE activation will be discussed. A. Grudiev and W. Wuensch, Proceedings of LINAC2010, Tsukuba, Japan, pp. 211 - 213
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME005
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Paper

Title

Page

Enhanced Field Emission and Emitter Activation on Flat Dry-ice Cleaned Cu Samples

2261

S. Lagotzky, G. Müller, P. Serbun
Bergische Universität Wuppertal, Wuppertal, Germany
S. Calatroni, T. Muranaka
CERN, Geneva, Switzerland

Enhanced field emission (EFE), resulting in dark currents and electric breakdowns, is one of the main gradient limitations for the CLIC accelerating structures (actual design Eacc = 100 MV/m, Epeak = 240 MV/m *). Measurements on diamond-turned, flat (Ra = 158 nm) Cu samples showed first EFE at surface fields Es = 130 MV/m. In order to reduce EFE, we have installed a commercial dry ice cleaning (DIC) system in a clean room environment (class iso 5). Accordingly, the number density of emitters (N) was significantly decreased by DIC from N = 52 /cm² to N = 12 /cm² at Es = 190 MV/m. Furthermore we have tested two diamond-turned and chemically etched (SLAC treatment, Ra = 150 nm) Cu samples after DIC resulting in EFE onset at 230 MV/m. Locally measured I(V) curves of the strongest emitters yielded field enhancement factors b = 10 – 90 (10 – 85) on the diamond-turned (chemically etched), respectively. SEM and EDX investigations of the located emission sites revealed surface defects and few particulates (Al, Ca, Si) as origin of the EFE. Moreover, strong emitter activation effects were observed. A possible breakdown mechanism based on this EFE activation will be discussed.
* A. Grudiev and W. Wuensch, Proceedings of LINAC2010, Tsukuba, Japan, pp. 211 - 213

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME005

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)