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OUTLINE Concept Development of a He - beam Development of a HeH + beam

R & D Status of Beam Neutralization System M. Sasao, K. Shinto, M. Okamoto, S. Kitajima, N. Tanaka, M. Nishiura, O. Kaneko, H. Sakakida, and M. Wada Tohoku Univ. NIFS, AIST,and Doshisha Univ. OUTLINE Concept Development of a He - beam Development of a HeH + beam

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OUTLINE Concept Development of a He - beam Development of a HeH + beam

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  1. R & D Status of Beam Neutralization SystemM. Sasao, K. Shinto, M. Okamoto, S. Kitajima, N. Tanaka, M. Nishiura, O. Kaneko, H. Sakakida, and M. WadaTohoku Univ. NIFS, AIST,and Doshisha Univ. • OUTLINE • Concept • Development of a He- beam • Development of a HeH+ beam • Measurement of He* fraction • Summary and Future work

  2. Typical Beam parameter: He0, from auto-detached He-, 10 mA, 5cm x 20cm, 0.1 mA/cm2 Accelerated up to 1.5-1.8 MeV He0 in the ground state Beam Source 26 m He++ + He0 => He0 + He++ Beam dump Analyzer Concept of a He- beam He++ + He0 => He0 + He++ RFQ + HV stage (above) 1m x 1m  + 1m x 1m x 3m Measuring point Detection point

  3. Pencil beam system for POP Optimization of He+ beam Characterization of beams Optimization of Alkali gas cell Phase space change by charge exchange cell Optimaization of Beam optics Measurement of metastable fraction Full Size He+ source Test at NIFS NBI test stand SDS(System Design Study) for ITER He+ beamlets Lens Double focus mass separator/lens Na/Rb cell Ion source Lens Main acceleration Free flying tube Development of a He- beam (1)M. Sasao, K. Shinto, et al. Milestones He-,He0 He+ 10 mA He+ 10 A He- Tohoku Univ. He- Test System

  4. 絶縁碍子上に高圧ステーションを構成(100-200kV)絶縁碍子上に高圧ステーションを構成(100-200kV) Development of a He- beam (2)Pencil beam system for POP 飛行管用貫通孔（隣の実験室へ） He+イオン源 偏向電磁石 アルカリ金属ガスセル

  5. 絶縁碍子上に高圧ステーションを構成(100-200kV)絶縁碍子上に高圧ステーションを構成(100-200kV) Development of a He- beam (3)Full Size model 飛行管用貫通孔（隣の実験室へ） He+イオン源 偏向電磁石 アルカリ金属ガスセル

  6. Typical Beam parameter: He0, from a HeH+, 20 mA, 5cm x 20cm, 0.2 mA/cm2 Accelerated up to 1.5-1.8 MeV He0 in the ground state Separation Acceleration Neutralization 10% Produced He0beam energy (keV) HeH+ 2 mA/cm2 He0 0.2 mA/cm2 Concept of a HeH+ beam RFQ + HV stage (above) 1m x 1m  + 1m x 1m x 3m Measuring point Detection point

  7. Development of a HeH+ beam H. Sakakida, et al. The conditions producing HeH+ beam were not investigated in detail as yet. Therefore, the optimum conditions to extract HeH+ beam have been explored using our beam system. In order to measure beam species, mass spectrometer, whose energy range is limited less than 500 eV, is used. Therefore, DC power supply of 300 V is used for the beam acceleration (here, -4.5 kV is applied to the deceleration electrode for efficient beam extraction). Figure shows the number of HeH+, He+ and H+ ions as a function of He gas pressure ratio to the total gas pressure of the mixture gas (He and H2) in the case of low energy 300 eV and ~6 A beam.It is clear that the production rate of HeH+ increases, when He pressure ratio is larger than ~75 %. In the case of 90 % ratio, the number of HeH+ particles corresponds to ~15 % of total counts for HeH+, He+ and H+ ions. In the case of high energy 25 keV beam, if 15 % of the total current of 40 A, (which includes H+, H2+, H3+, He+ and HeH+ components) is the HeH+ component, the current density of HeH+ is ~13 mA/cm2, which is sufficient for the primary beam in the measurement of ITER.

  8. Measurement of He* fraction M. Okamoto

  9. Development of a He- beam is on going in 3 sub-groups in parallel, [1] Pencil beam system for Proof Of Principle [2] Full Size He+ source [3] System Design Study for ITER The option of a HeH+ source is promising as an alternative probing beam. Several measurement methods of He* fraction are proposed and their principles will be tested. Summary and crucial issues

  10. Development of a He- beam is on going in 3 sub-groups in parallel, [1] Pencil beam system for POP [2] Full Size He+ source [3] System Design Study for ITER The option of a HeH+ source is promising as an alternative probing beam. Several measurement methods of He* fraction are proposed and their principles will be tested. It is crutial to keep a tangential port at #6. Is it possible to send the argument- from diagnostic point of veiw? (although 99% is on the current drive, and blanket test.) Example: Various important phenomena which should be studied on ITER require 2D imaging. A tangential port can be used for various 2D imaging (X-ray, VUV, visible, bolometric, neutrons, gamma’s, etc.), in addition to the beam alpha-particle diagnostics. Summary and crucial issues

  11. It is crutial to keep a tangential port at #6. - Summary and Future work

  12. Conclusion

  13. Conclusion

  14. Conclusion

  15. Conclusion

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