Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Facility overview Ion sources at COSY R&D details Cs ionizer Extraction Actual investigations (ABS, LSP) Summary and outlook Polarized H - and D - Beams at COSY/J ü lich

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 The COSY Facility 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 COoler SYnchrotron

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 The COSY Injector

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Light Ions for COSY

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Charge exchange reaction H 0 (D 0 ) + Cs 0  H - (D - ) + Cs + The COSY Polarized Source RF discharge Thermal ionizer 38 K 1150 K 550 K

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 The COSY Polarized Source

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Atomic Beam Source Cesium Ionizer and Beam Line The COSY Polarized Source (II)

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Cs Ionizer – Replacement of the Prototype S. Lemaitre’s and R. Reckenfelderbäumer’s Ph.D. theses NIM A 408, 345 (1998)

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Tungsten Ionizer

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Next Iterations M. Eggert’s Ph.D. thesis NIM A 454, 514 (2000)

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Pulsed Version

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 dc and pulsed operation ( Hz) 6 mA 45keV – 25 ms 0.5 Hz up to 1500 hours continuous operation for COSY and experiments 3 sources for exchange Development of Cs + Sources -4 kV -5 kV -6 kV -7 kV -7.5 kV mA Emitted Cs + current 5.5 mA 20 ms 55°C 60°C 65°C

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 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 Focusing the Cesium Beam

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Field Gradient inside the Solenoid

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Beam Current vs.  U and  B 

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Extraction and Deflection

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Improvement of Beam Extraction H - Cs +, Cs 0 Mounting the extraction elements

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Focusing the Atomic (H, D) Beam Monte-Carlo simulation Integration over r, r’, spin and velocity Radius [mm] Distance to 2nd hexapole [m] 60 % 70 % 80 % 90 % Solenoid

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Exchange of the EM hexapoles EM diameter 220 mm PM diameter 80 mm 220 mm M. Altmeier’s and O. Felden’s Ph.D. theses NIM A 626, 117 (1997)

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 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

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Estimation of density and velocity The density was measured with a TOF mass spectrometer. Figure of merit = density / v² (magnet acceptance ~ 1/T)

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Dissociator Development

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Dissociator Development

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Dissociator Development

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Improved Density with new Design

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Lambshift Polarimeter

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Lambshift Polarimeter Ready for first beam!

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Summary: Intensity record for deuterons unpolarized deuterons switching to polarized deuterons

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Summary: Intensity and polarization Beam current at the source exitPolarization inside COSY Data from Exp. EDDA (pp – elastic scattering) P avg = (91.4  2.2 ) %

Institute for Nuclear Physics Ralf Gebel – PSTP 2007 – September 2007 Outlook Beam for the Lambshift Polarimeter Improved atomic beam stage for COSY Operation Thank you! Acknowledgments: A.S. Belov (ABS, LSP...) R. Engels (LSP)