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ECR ion source for the highly charged, intensive ion beams

University of Jyväskylä, Department of Physics. ECR ion source for the highly charged, intensive ion beams. H. Koivisto. Content. 1. Production of highly charged ion beams (by ECRIS). 2. Present projects and challenges. 3. (Metal) Ion beam production . 4. Beam transport .

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ECR ion source for the highly charged, intensive ion beams

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  1. University of Jyväskylä, Department of Physics ECR ion source for the highly charged, intensive ion beams H. Koivisto ESF-Workshop, Athens, Greece

  2. Content 1. Production of highly charged ion beams (by ECRIS) 2. Present projects and challenges 3. (Metal) Ion beam production 4. Beam transport ESF-Workshop, Athens, Greece

  3. What kind of ion source? Accelerator (linear/cyclotron) gives some boundary condition! - Continues or pulsed beam? - A+ or Aq+(low versus high charge states)? - Intensity requirement? - Variety of elements? Charge breeding? Etc... ECRIS ESF-Workshop, Athens, Greece

  4. Operation principle (ECRIS) 1) Sufficient magnetic field (including correct structure) 2) Electrons rotating in magnetic field 3) Microwaves ECR: Electron Cyclotron Resonance ESF-Workshop, Athens, Greece

  5. 14 GHz : 0.5 T 28 GHz: 1 T V E N U S Scaling laws (magnetic, frequency) 1) Magnetic field: Axial magnetic field Baxial by solenoids Radial magnetic field Bradial by multipole ESF-Workshop, Athens, Greece

  6. Scaling laws 2) Frequency R. Geller proposed: as high microwave frequency as possible is wanted! PROBLEM: Higher magnetic field is required!! ESF-Workshop, Athens, Greece

  7. ECRIS generations 1st generation: 6.4 GHz MSU RT-ECRIS, TAMU 6.4 GHz, etc 2nd generation: 14 GHz ECRIS AECR, Artemis, Caprice, etc. 3rd generation: 28 GHz VENUS, SECRAL, several under construction: Requires SC-technique! ESF-Workshop, Athens, Greece

  8. The requirements of next generation heavy ion facilities made the development of 3rd Generation sources (and maybe 4th Generation) ECR ion sources necessary SECRAL, Lanzhou, China H. Zhao VENUS, 270 eµA U33+ and 270 eµA U34+ SC-ECRIS, RIKEN, Japan 525 eµA U35+ 50-100 eµA U41+ SuSI NSCL,USA MS ECRIS GSI, Germany SPIRAL 2, GANIL, France ESF-Workshop, Athens, Greece 1mA Ar12+

  9. ESF-Workshop, Athens, Greece

  10. Motivation: 1mA Ar12+ for the SPIRAL II Project Optimization of the VENUS source for Ar12+ to demonstrate the ‘tuning’ of the plasma parameters ESF-Workshop, Athens, Greece

  11. ECRIS-56 Becr= 2 T Binj ~ 8 T Bext= 4 T Brad= 4 T Comparison of different generations 1st generation:Itot<1 mA 2nd generation:Itot= 2-4 mA 3rd generation:Itot= 10 mA Beyond present technological know-how! ESF-Workshop, Athens, Greece

  12. MS-ECRIS won’t be a 4th generation ECRIS even if 56 GHz can be tested It won’t fulfill the scaling law for the magnetic fields! It will be a step between the 3rd and 4th generation ECRIS (3.5 generation) 4th generation ECRIS requires a lot of development work for example in the field of superconductive technique ESF-Workshop, Athens, Greece

  13. Some engineering current densities ESF-Workshop, Athens, Greece

  14. Different Nb3Sn-structures ESF-Workshop, Athens, Greece

  15. Cryostat and Cold Mass From Claude Lyneis Cryocooler Flange • Bremsstrahlung created in collisions of energetic electrons with the plasma chamber walls produce a high flux of x-rays. • A fair amount of this energy is deposited in the cryostat • With the original Al plasma chamber: • 1 W/kW 28 GHz (only 2 W cooling power available) • 150mW/kW for 18 GHz • High voltage insulation deteriorates in the high x-ray flux LN Reservoir (70 K) LHe Reservoir (4.2 K) Vacuum Vessel 50 K Shield Warm Bore Plasma Chamber Cold Masswith Coils Enclosed Bremsstrahlung will be a serious problem! Iron Yoke Links ESF-Workshop, Athens, Greece

  16. Challenges for 4th generation ECRIS - superconducting wire to reach required B-field - bremsstrahlung (heating of cryostat) - cooling of plasma chamber (power up to tens of kW) - coupling of microwaves to plasma - efficient extraction to handle multi tens of mA beam ESF-Workshop, Athens, Greece

  17. Production of metal ion beams ECOS working group: “In order to meet the requirements of the future experiments with high-intensity beams, further development is needed, especially in the production of metal-ion beams. Consequently, the development of ECR ion source will be one of the most active areas in accelerator physics.” Consequently a lot of human resources will be invested in this work (very visible role during FP7) ESF-Workshop, Athens, Greece

  18. Different methods: High temperature ovens: - inductively heated oven (above 2000˙C) ESF-Workshop, Athens, Greece

  19. resistively heated oven (above 2000˙C)) - sputtering (some refractory elements) - laser ablation? ESF-Workshop, Athens, Greece

  20. Beam transport More beam intensity from the cyclotron is needed for the experiments!! Improvement of ECRIS performance does not always increase the intensity for the experiments beam formation or/and transmission problem!! Problem in several laboratory! ESF-Workshop, Athens, Greece

  21. Statistics (2004) Icycl/IECR JYFL 14 GHz ECRIS 2nd harmonic Transmission efficiency decreases when beam intensity increases! Some reasons: 1) space charge effect (strong focusing) 2) Emittance increases with beam intensity ESF-Workshop, Athens, Greece

  22. DIMAD simulations (by X. Wu) Beam spot in viewer according to DIMAD-simulations Beam spot in viewer (just after dipole) ESF-Workshop, Athens, Greece

  23. JYFL NSCL Hollow beam ESF-Workshop, Athens, Greece

  24. “ECOS” needs the development of: - ion sources for higher intensity and higher charge states • beam formation to produce high quality beams - high quality beam transport facility to transport beam efficiently to accelerator • development of metal ion beam production to make new • and exotic beams available ESF-Workshop, Athens, Greece

  25. Thanks to the following for providing slides for this presentation: - Santo Gammino - Daniela Leitner - Claude Lyneis - Marc Doleans ESF-Workshop, Athens, Greece

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