1. Flipping proton and deuteron spins in storage rings L.I. Malysheva

2. 1/06/07 Liverpool Christmas meeting The University of Liverpool/Cockcroft Institute L I Malysheva Motivation A high intensity polarised beams are an essential tool Past: VEPP, HERA, LEP, AmPS… NOW: COSY, RHIC Future: LHeC, FAIR, eRHIC, JPARC, Super-B, ( ILC? ) Radio-frequency (RF) methods for spin manipulation: a) Spin-flipping technique: Stable and fast b) Beam Energy Calibration using resonance depolarisation c) Polarimeter calibration Use of RF dipoles or Solenoids

3. 1/06/07 Liverpool Christmas meeting The University of Liverpool/Cockcroft Institute L I Malysheva Polarisation for spin-1/2 and spin-1 particles SPIN-1/2 density matrix SPIN-1 density matrix are tensor polarisation components. ( Irreducible tensor of rank 2 )

4. 1/06/07 Liverpool Christmas meeting The University of Liverpool/Cockcroft Institute L I Malysheva SPIN PRECESSION ( THOMAS-BARGMANN-MICHEL-TELEGDI ) Spin-tune where Note

5. 1/06/07 Liverpool Christmas meeting The University of Liverpool/Cockcroft Institute L I Malysheva Single Resonance Model (SRM) and spin-flipping Analogous to NMR RF transverse field Froissart –Stora formulawhere is the rate of resonance crossing is resonance strength : The value can be extracted from experiments data. Unexpected or misinterpreted?? If SRM expected

6. 1/06/07 Liverpool Christmas meeting The University of Liverpool/Cockcroft Institute L I Malysheva COSY is a cooler synchrotron and storage ring Length: 180 m closed loop vacuum tube. momentum range: 600 ---3700 MeV/c ( 175 -- 2880 MeV). "internal experiments : experiments with the circulating beam "external experiments": experiments with the extracted beam "COoler SYnchrotron" Tests ongoing to evaluate the technique of spin-flipping

7. 1/06/07 Liverpool Christmas meeting The University of Liverpool/Cockcroft Institute L I Malysheva ISF as a new tool for evaluation of spin-flipping technique Froissart-Stora formula is based on SRM If the naive SRM does not provide a sufficient description, then expect some unexpected behaviour ! Two views to follow: 1) Using Froissart-Stora formulae and DEPOL program… 2) DESY expertise based on application of Invariant Spin Field (ISF) concept: If ISF exists (all parameters fixed) then (A.I.) The SRM can be solved exactly analytically or numerically The stroboscopic averaging algorithm provides a reliable tool for calculating ISF in the presence of RF dipoles. Investigate static spin configuration for fixed frequencies

8. 1/06/07 Liverpool Christmas meeting The University of Liverpool/Cockcroft Institute L I Malysheva Simple Model To test concept: simplified model of COSY Ring was used: only dipoles and quadrupoles. Real parameters There are 2 effects associated with presence of RF dipole in the lattice: Direct effect on spin motion Contribution to the resonance strength due to forced betatron oscillation

9. 1/06/07 Liverpool Christmas meeting The University of Liverpool/Cockcroft Institute L I Malysheva INVARIANT SPIN FIELD COMPONENTS: RF Dipole only

10. 1/06/07 Liverpool Christmas meeting The University of Liverpool/Cockcroft Institute L I Malysheva INVARIANT SPIN FIELD COMPONENTS in the presence of betatron motion

11. 1/06/07 Liverpool Christmas meeting The University of Liverpool/Cockcroft Institute L I Malysheva Frequency scans Vertical component of ISF Q RF QyQy Q y -Q RF 2QRF

12. 1/06/07 Liverpool Christmas meeting The University of Liverpool/Cockcroft Institute L I Malysheva Status and Future plans Go beyond the usual superficial view on the topic: various diagnostics is build in dedicated code Simulations for protons confirm strong enhancement in resonance strength vs. nominal RF dipole strength. Now: check against Froissart-Stora simulation on ISF – ongoing Next: proton and deuteron simulation on the real ring (Using SPRINT) to try to disentangle COSYs spin-flip mysteries