Measurements of Linac4 H− ion source beam with a magnetized Einzel lens electron dump

Abstract

Linac4 is a part of the upgrade of CERN's accelerator complex for increased luminosity in the LHC. A new system to extract the ion beam from the plasma generator has been designed and tested, in order to improve the reliability and beam optics of the pulsed H -ion source. This paper presents the successfully implemented extraction system and three different beam measurements. The simulations compare well to the measurements and show that the plasma density was too low for the extraction system design during the measurements. Linac4 is a part of the upgrade of CERN's accelerator complex for increased luminosity in the LHC. A new system to extract the ion beam from the plasma generator has been designed and tested, in order to improve the reliability and beam optics of the pulsed H − ion source. This paper presents the successfully implemented extraction system and three different beam measurements. The simulations compare well to the measurements and show that the plasma density was too low for the extraction system design during the measurements.

Optimization of the beam extraction systems for the Linac4 H− ion source

“…IBSimu has already been successfully applied to design the extraction system for the DESY-type ion source operated in volume production mode. The results of the simulation are in good agreement with the observed currents and emittances [5,8,9]. The final designs of the extraction systems presented in this paper are the result of iteratively optimizing the geometry within the geometrical constraints of the Linac4 ion source frontends and the subsequent LEBT, as well as the voltage ranges of the available power supplies.…”

A Study on the negative ion beam production in the ININ sputtering ion source

“…The total space charge deposition (SCD) of all the ions involved in the simulation can be estimated with the Eq. 2 [16], where I x the current from the particle x, assuming the electrons to Cs + ratio as one, the space charge is widely dominated by the Cs + ions by its mass and intensity and the inclusion of the electrons and ion beam does not change the Cs particles trajectories significantly as the simulations confirm.…”

“…The current ratio yield J H − /J Cs + defines the negative beam emission from the cathode surface as the Cs ions collide, the accelerator operation shows a ratio close to 0.02 [16], and it will remain fixed for all this work.…”

Status and operation of the Linac4 ion source prototypes

“…A detailed analysis of the beam optics and magnetized einzel lens based low energy dumping of co-extracted electrons 12 predicted the typically 0.5-0.6 πmm•mrad H -beam emittance measured in the LEBT 13 . A detailed analysis of the beam parameters and high voltage currents shed light on the presence of secondary electrons that are captured by the electric fields 14 and should be included in beam simulation. The hydrogen density regulation in the LEBT is operational and the effect of space charge compensation due to rest gas ionization was measured 15 .…”