The Polarized Internal Target at ANKE: First Results

1. The Polarized Internal Target at ANKE:First Results Kirill Grigoryev Institut für Kernphysik, Forschungszentrum Jülich PhD student from Petersburg Nuclear Physic Institute (PNPI), Gatchina, Russia Kyoto October 03, 2006

2. COSY  COoler SYnchrotron ANKE at COSY →→ p, p, d, d • Magnets • D2 – spectrometer magnet • D1, D3 – beam bending magnets • Detector systems • Positive & Negative • Forward & Backward • Spectator Detectors with momenta up to 3.7 GeV/c • internal experiments – • with the circulating beam • (ANKE, COSY-11, EDDA) • external experiments – • with the extracted beam • (BIG KARL, TOF) • Targets • Solid strip • Cluster jet • Polarized gas cell • ( polarized gas jet ) Spectrometer ANKE Kirill Grigoryev @ SPIN2006

3. Polarized Internal Gas Target • Summer 2003– Atomic Beam Source is ready for using in experiments • End of 2004 – Start of the PIT transportation to the COSY experimental hall • PIT main components: • ABS • H orD • H beam intensity (2 HFS) • 7.6 . 1016 atoms/s • Beam size at the IP • σ = 2.85 ± 0.42 mm • Polarization for hydrogen • PZ = 0.89 ± 0.01 • PZ =-0.96 ± 0.01 • Lamb-Shift Polarimeter • Target chamber with Storage Cell • Summer 2005 – After commissioning source is ready for installation at COSY • July 2005 – ABS is installed at the ANKE-experiment area at COSY Work only begins ABS with infrastructure at the COSY experimental hall Setup at the COSY experimental hall Setup at ANKE at COSY Setup at the laboratory Kirill Grigoryev @ SPIN2006

4. Magnetic Stray Field from D2 Magnet ABS with shielded components at ANKE Kirill Grigoryev @ SPIN2006

5. Test of the Medium-field RF-Transition Unit No dependence of MFT on D2 field  Shielding ok Kirill Grigoryev @ SPIN2006

6. PIT at ANKE Using of the ABS at ANKE with storage cell jet target An additional methods to improve COSY beam Beam scraping Stochastic cooling Electron cooling Stacking at injection Kirill Grigoryev @ SPIN2006

7. ABS-jet test with catcher Measured pressures in the target chamber, mbar ABS Beam COSY Beam integralthickness ~ 1.5 . 1011 cm-2 ~13cm Number of events ABS beam catcher Kirill Grigoryev @ SPIN2006

8. Storage cell setup Kirill Grigoryev @ SPIN2006

9. Cooler Stacking with the Storage Cell Stored particles in the ring = 6.4 · 109 protons H target thickness = 2 · 1013atoms/cm2 Average luminosity > 1029 cm-2s-1 & 28 stacks with 2s electron cooling acceleration to Tp=600 MeV after 58s from cycle start Kirill Grigoryev @ SPIN2006

10. Stochastic cooling Tp=831 MeV Cooling off Cooling on • Length of the cycle = 10 min • Minimum energy for stochastic cooling is 831MeV Kirill Grigoryev @ SPIN2006

11. PIT commissioning Clear spotof the events from the cell-target gas pp→dπ+ reaction Cell feeding with Nitrogen helps to obtain background from interactions with the cell wall Kirill Grigoryev @ SPIN2006

12. Target polarization from nuclear reaction Used HFS 1 and 2 (only MFT). WFT would provide higher polarization in state 3, but did not work. Tp=831 MeV – HFS1 – HFS2 Assuming both polarization P+ and P- were equal  P = 0.44±0.03 Theoretically we expect P+=0.85 and P-=-0.27(-0.18)  P= 0.56 (0.51) Kirill Grigoryev @ SPIN2006

13. Future plans ongoing – Teflon coating and new cell production Autumn ’06–studies of nuclear polarization of molecules from recombined polarized H and D atoms use of the ABS in the other project ( ISTC #1861 ) December ’06 –PIT reinstallation with Lamb-shift polarimeter at ANKE January ’07 –First double polarized experiment:dp → (pp)n →→ see talk D. Chiladze Kirill Grigoryev @ SPIN2006

14. Do we have zero field crossings along the ABS axis? Magnetic field scan with ANKE at 5.3º using a 3D Hallprobe (Gatchina): • Magnetic field along ABS axis • ID2 = 563 A • ID1D3= 1294.84 A • Determine the local Larmor precession frequency ωL • The angular velocity of the magnetic field ωB. • As long as the ratio R=ωL/ωB is large, the spin of the atom follows the field direction. •  no depolarization • due to zero crossings Kirill Grigoryev @ SPIN2006