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Author(s)
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Lettry, J (CERN) ; Bertolo, S (CERN) ; Fantz, U (Garching, Max Planck Inst.) ; Guida, R (CERN) ; Kapusniak, K (CERN) ; Di Lorenzo, F (CERN) ; Machado, C (CERN) ; Mastrostefano, C (CERN) ; Minea, T (LPGP, Orsay) ; O'Neil, M (CERN) ; Neupert, H (CERN) ; Noll, D (CERN) ; Steyaert, D (CERN) ; Thaus, N (CERN) |
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Abstract
| The 2MHz radio-frequency inductively coupled plasma heating (ICP RF) of Linac4’s IS03 H-
source is more
efficient without its octupole cusp in offset hallbach configuration. This was shown by Particle in cell Monte-Carlo (PICMC) simulation using the NINJA software [1] and confirmed by plasma characterization via optical emission spectroscopy
[2,3], an easier plasma ignition is also anticipated. In this paper, we present preliminary results of an Alumina plasma
chamber IS03 H-
source [4] operated without magnetic cusp. Operation under monthly cesiation induces a slow evolution
of the molybdenum cesiated surface correlated with an increase of the co-extracted electron yield. An improved stability
of the extracted H-
beam is achieved by compensating the Cs-losses.
The high intensity option for Linac4 features an adaptation of BNL’s Magnetron. Simulation of this complex H2-Cs arc
discharge plasma, where electrons are emitted from a cesiated molybdenum cathode, requires characterization of the plasma
impedance and knowledge of hydrogen and cesium densities. We present a measurement of plasma impedance over the
range of discharge current, hydrogen and cesium-densities. |