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Polarized H - and D - Beams at COSY/J ü lich

Polarized H - and D - Beams at COSY/J ü lich. Facility overview  Ion sources at COSY R&D details Cs ionizer Extraction Actual investigations (ABS, LSP) Summary and outlook. The COSY Facility. CO oler SY nchrotron. 0.6 .. 3.65 GeV/c p and d polarized beams

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Polarized H - and D - Beams at COSY/J ü lich

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  1. Polarized H- and D- Beams at COSY/Jülich • Facility overview  • Ion sources at COSY • R&D details • Cs ionizer • Extraction • Actual investigations (ABS, LSP) • Summary and outlook

  2. The COSY Facility COoler SYnchrotron • 0.6 .. 3.65 GeV/c p and d • polarized beams • beam cooling • internal and external detectors for the investigation of nuclear quark structure and dynamics, fundamental symmetries and e.g. exotic mesons, rare decays

  3. The COSY Injector

  4. Light Ions for COSY

  5. RF discharge Thermal ionizer Charge exchange reaction H0(D0) + Cs0 H-(D-) + Cs+ The COSY Polarized Source 1150 K 38 K 550 K

  6. The COSY Polarized Source

  7. The COSY Polarized Source (II) Atomic Beam Source Cesium Ionizer and Beam Line

  8. Cs Ionizer – Replacement of the Prototype S. Lemaitre’s and R. Reckenfelderbäumer’s Ph.D. thesesNIM A 408, 345 (1998)

  9. Tungsten Ionizer

  10. Next Iterations M. Eggert’s Ph.D. thesisNIM A 454, 514 (2000)

  11. Pulsed Version

  12. Development of Cs+ Sources -7.5 kV Emitted Cs+ current 12 -7 kV Emitted Cs+ current 8 -6 kV mA -5 kV 65°C 4 -4 kV 60°C 5.5 mA 0 55°C 20 ms • dc and pulsed operation (0.5- 3 Hz) • 6 mA routinely @ 45keV – 25 ms 0.5 Hz • up to 1500 hours continuous operation for COSY and experiments • 3 sources for exchange

  13. Focusing the Cesium Beam • A set of computer controlled wire scanners • for Cs+/o diagnosis • to judge the beam and the ionizer quality • to optimize Cs+/o transmission • space charge compensation by adding Argon

  14. Field Gradient inside the Solenoid 1994 2005

  15. Beam Current vs. U and B

  16. Extraction and Deflection

  17. H- Cs+, Cs0 Improvement of Beam Extraction Mounting the extraction elements

  18. 90 % 25 20 Solenoid 80 % 20 70 % Radius [mm] Radius [mm] 60 % 15 0 10 5 -20 0 0.0 0.0 0.4 0.5 0.8 1.0 1.2 1.5 1.6 Distance to 2nd hexapole [m] Distance to 2nd hexapole [m] Focusing the Atomic (H, D) Beam Monte-Carlo simulation Integration over r, r’, spin and velocity

  19. Exchange of the EM hexapoles 220 mm EM diameter 220 mm PM diameter 80 mm M. Altmeier’s and O. Felden’s Ph.D. thesesNIM A 626, 117 (1997)

  20. Neutral Beam Profile Scanner Estimation of the atomic beam size and position by using the Cs scanner inside the atomic beam part and a compression tube

  21. Estimation of density and velocity The density was measured with a TOF mass spectrometer. Figure of merit = density / v² (magnet acceptance ~ 1/T)

  22. Dissociator Development

  23. Dissociator Development

  24. Dissociator Development

  25. Improved Density with new Design

  26. Lambshift Polarimeter

  27. Lambshift Polarimeter Ready for first beam!

  28. Summary: Intensity record for deuterons unpolarized deuterons switching to polarized deuterons

  29. Pavg = (91.4  2.2 ) % Data from Exp. EDDA (pp – elastic scattering) Summary: Intensity and polarization Beam current at the source exit Polarization inside COSY

  30. Outlook • Beam for the Lambshift Polarimeter • Improved atomic beam stage for COSY Operation Thank you! Acknowledgments: A.S. Belov (ABS, LSP...) R. Engels (LSP)

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