Status and new developments of the high intensity electron cyclotron resonance source light ion continuous wave, and pulsed mode (invited)

Abstract

The high intensity light ion source (SILHI) is the electron cyclotron resonance (ECR) source constructed and tested at CEA-Saclay. The first aim is to produce up to 100 mA cw proton beams at 95 keV for the proton injection high intensity (IPHI) beams [5 MeV radio frequency quadrupole (RFQ) and 10 MeV drift tube linac (DTL)]. This prototype is developed by a CEA–CNRS-IN2P3 collaboration for applications such as accelerator driven systems for nuclear waste transmutation, production of radioactive ion beams or secondary particles. SILHI is also used to study the production of deuteron and H− beams for the International Fusion Material Irradiation Facility and European spallation source projects, respectively. The present status of SILHI and the experiments planned for the near future in both cw and pulsed modes are presented in this article. 80 mA cw proton beams are now currently produced at 95 keV with a high availability (∼1 spark/day). The proton fraction is around 90% and the typical r–r′ rms normalized emittance after transport through a single solenoid low energy beam transport (LEBT) without beam losses is 0.3 πmm mrad. The best beam characteristics are obtained when an ECR zone is created at the frontier between the plasma chamber and the rf ridged transition. Extensive emittance measurements performed with different gas injection in the LEBT have shown a factor of three emittance reduction. Space charge compensation measurements in cw mode will be undertaken with a four-grid analyzer to understand this behavior. Time resolved space charge compensation measurements in pulsed mode are also discussed. The highest total beam current of 120 mA (240 mA/cm2) can be extracted with two ECR zones located at the plasma chamber extremities. Nevertheless a new electrode design must be done for this configuration to avoid excessive beam losses in the extraction system.