High Precision Spin Manipulation at COSY

Matter and Technologies High Precision Spin Manipulation at COSY Sebastian Mey Hamburg, February 26, 2015 Forschungszentrum Jülich

2 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY Spin Motion in a Storage Ring Content 1 Spin Motion in a Storage Ring 2 COSY as Spin Physics R&D Facility 3 Measurements: Horizontal Polarization 4 Measurements: Vertical Polarization 5 Conclusion

3 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY Spin Motion in a Storage Ring Spin Motion in a Storage Ring Thomas-BMT Equation: d S dt ( Ω = q m = S Ω (1 + γg) B + (1 + G) B ( ) γ γ + 1 + γg E β ) c

4 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY Spin Motion in a Storage Ring Free Precession Thomas-BMT Equation: d S dt ( Ω = q m = S Ω (1 + γg) B +(1 + G) B ( ) γ γ + 1 + γg E β ) c ideal ring: only main bending dipoles additional spin precession per turn due to anomalous magnetic moment G spin tune ν S = γg is relative number of precessions per turn! vertical polarization component S y is constant B main y S β z Ω

5 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY Spin Motion in a Storage Ring Driven Oscillation Thomas-BMT Equation: d S dt ( Ω = q m = S Ω (1 + γg) B + (1 + G) B ( ) γ γ + 1 + γg E β ) c additional perturbation field leads to tilt of precession axis oscillating RF field in phase with spin precession will lead to accumulation of spin kicks rotation of S in vertical plane oscillation of S y resonant at all side bands f S = n + ν s f rev ; n Z resonance strength is defined as vertical spin rotation per revolution B z Ω z β y B main x

5 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY Spin Motion in a Storage Ring Driven Oscillation Thomas-BMT Equation: d S dt ( Ω = q m = S Ω (1 + γg) B +(1 + G) B ( ) γ γ + 1 + γg E β ) c additional perturbation field leads to tilt of precession axis oscillating RF field in phase with spin precession will lead to accumulation of spin kicks rotation of S in vertical plane oscillation of S y resonant at all side bands f S = n + ν s f rev ; n Z resonance strength is defined as vertical spin rotation per revolution B main y z β Bx Ω x

6 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY COSY as Spin Physics R&D Facility Content 1 Spin Motion in a Storage Ring 2 COSY as Spin Physics R&D Facility 3 Measurements: Horizontal Polarization 4 Measurements: Vertical Polarization 5 Conclusion

COSY as Spin Physics R&D Facility εx,y and RF solenoid RF ExB dipole p control p beam cooling experiments with ~d @ 970 MeV/c G = 0.142 γ G = 0.161 frev = 750 khz fs = 120 khz fast, continuous polarimetry polarized source [ talk by V. Kamerdzhiev] 7 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY COSY as Spin Physics R&D Facility

8 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY Measurements: Horizontal Polarization Content 1 Spin Motion in a Storage Ring 2 COSY as Spin Physics R&D Facility 3 Measurements: Horizontal Polarization 4 Measurements: Vertical Polarization 5 Conclusion

9 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY Measurements: Horizontal Polarization Fast Polarimetry massive carbon target as defining aperture, use slow extraction beam polarization average over all particles spins asymmetries in 12 C( d, d): P y ɛ lr = N left N right N left + N right ; P x ɛ ud = N up N down N up + N down since 2012: high resolution timestamping for every event Beam Target position along ring / m bunch-shape evolution per fill all events left, right up, down time in cycle / s [ Z. BAGDASARIAN et al., Phys. Rev. ST Accel. Beams 17, 052803 (2014)]

10 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY Measurements: Horizontal Polarization Horizontal Polarization Measurement use RF flipper to rotate polarization in horizontal plane accumulate data in time bins time stamping determination of up-down-asymmetry signal in every bin: P x (t) ɛ sin(2πν s f rev t + φ) amplitude ɛ corresponds horizontal polarization 0.3 amplitude 0.2 0.1 0.0 0.160970 0.160975 0.160980 0.160985 spin tune ν0 s [D. Eversmann, JEDI Collaboration]

11 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY Measurements: Horizontal Polarization Spin Tune Evolution fix determined spin tune to all other macroscopic bins observe phase evolution φ(t) over whole cycle correlation of data from all time bins total spin tune change over time given by derivative of phase φ ν s (t) = νs 0 + 1 d φ = 0.1609752 + ν s (t) 2πf rev dt spin tune average over 100 s cycle determined to 10 9 (!) ϕ [rad] 6 number of particle turns [10 ] 0 10 20 30 40 50 60-4 -4.2-4.4-4.6-4.8-5 9 10 ν s 6 number of particle turns [10 ] 0 10 20 30 40 50 60 1 0-1 -2-5.2 0 10 20 30 40 50 60 70 80 90 time [s] [D. Eversmann, JEDI Collaboration] -3 0 10 20 30 40 50 60 70 80 90 time [s]

12 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY Measurements: Horizontal Polarization Long Time Stability ν s = 0.160 975 2 + ν s (t) [D. Eversmann, JEDI Collaboration]

13 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY Measurements: Horizontal Polarization Amplitude Evolution Spin Coherence Time spin precession frequency f s γg f rev averaging over particles spins use bunching to fix f rev for all particles energy spread γ γ spin tune spread use beam cooling to minimize ɛud τ t sct ɛ ud e τ sct 20 s [D. Eversmann, JEDI Collaboration]

14 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY Measurements: Horizontal Polarization Canceling 2 nd Order Effects with Sextupoles consider path lengthening effects γ γ L L ( x 2, y 2, δ 2 ) three independent families of COSY sextupoles at locations with large β x, β y, D to compensate ɛud ɛ ud e τ sct τ sct 400 s t [D. Eversmann, JEDI Collaboration]

15 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY Measurements: Vertical Polarization Content 1 Spin Motion in a Storage Ring 2 COSY as Spin Physics R&D Facility 3 Measurements: Horizontal Polarization 4 Measurements: Vertical Polarization 5 Conclusion

16 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY Measurements: Vertical Polarization The RF ExB dipole in Wien Filter Configuration RF B dipole ˆBx dz = 0.175 T mm RF E dipole Êy dz = 24.1 kv shielding Box ferrite blocks foil electrodes 50 µm stainless steel 3 10 200 coil 8 windings length 560 mm distance 54 mm length 580 mm 10 200 3 200 3 10 10 200 3 Fy / ev/m 100 0-100 eê y 100 ˆFy dz 0! Fy / ev/m = 0 Fy / ev/m 100 0-100 100 0 Fy / ev/m -200-0.05 0 0.05 x / m ecβ ˆBx -1-0.5 0 0.5 1 z / m -100-200 -200-0.05 0 0.05 x / m -1-0.5 0 0.5 1 z / m -100-200

2 2 17 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY Measurements: Vertical Polarization 2 2 Driven Polarization Oscillation Run3577 fpy: 0.2896 Hz, τ: 6.6399 s Run3584 fpy: 0.2167 Hz, τ: 4.7532 s fpy = 0.2012 Hz at f RF = 871.427713 khz min CR y 0.3 0.2 0.1 CR y 0.3 0.2 0.1 fpy / Hz 0.4 χ 2 / ndf 4.811 / 3 Curvature 1.73e+06 ± 9.91e+04 Minimum at 871.4 ± 5.632e-06 0-0.1-0.2 χ / ndf 81.37 / 95 cos Offset 0.1971 ± 0.0019 cos Phase -30.71 ± 11.85 cos Freq / Hz 0.2896 ± 0.0076 0-0.1-0.2 χ / ndf 81.98 / 95 cos Offset 0.1429 ± 0.0020 cos Phase -28.74 ± 4.81 cos Freq / Hz 0.2167 ± 0.0036 0.35 Offset 0.2012 ± 0.002057 3575-0.3 exp scale 0.04851 ± 0.00774 exp τ / s 6.64 ± 1.68 90 95 100 105 110 115 t / s -0.3 0.1202 ± exp scale 0.0104 τ / s 4.753 ± exp 0.574 90 95 100 105 110 115 t / s 0.3 CR y 0.3 Run3585 fpy: 0.2011 Hz, τ: 4.6804 s CR y 0.3 Run3574 fpy: 0.2827 Hz, τ: 6.7726 s 3577 3574 0.2 0.2 0.25 0.1 0.1 0-0.1-0.2-0.3 χ / ndf 121.9 / 95 cos Offset 0.02555 ± 0.00196 cos Phase -73.03 ± 4.50 cos Freq / Hz 0.2011 ± 0.0030 exp scale 0.1483 ± 0.0086 exp τ / s 4.68 ± 0.43 90 95 100 105 110 115 t / s 0-0.1-0.2-0.3 χ / ndf 85.36 / 95 cos Offset 0.1751 ± 0.0020 cos Phase -54.03 ± 8.89 cos Freq / Hz 0.2827 ± 0.0053 exp scale 0.05332 ± 0.01024 exp τ / s 6.773 ± 2.337 90 95 100 105 110 115 t / s 0.2 3584 3576 3585 871.4276 871.4278 871.428 f RF =(1-Gγ)f / khz rev total spin flip only on resonance average polarization 0 minimum of vertical polarization oscillation frequency f Py resonance strength is spin rotation per turn ε = f Py,min f rev

18 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY Measurements: Vertical Polarization Determination of Lorentz Force Compensation RF Wien filter at f S, 1 = 871.4277 khz scan of betatron tune q y determines influence of beam oscillations RF-solenoid: f Py = const.; RF-Wien-Filter: f Py = const. RF-dipole: interference with driven coherent beam osc. (2-qy)frev / khz 1126 0.35 1076 1026 976 926 876 826 0.30 0.25 fpy / Hz 0.20 0.15 0.10 0.05 preliminary data 0.00 0.450 0.550 0.650 0.750 0.850 0.950 qy

19 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY Conclusion Content 1 Spin Motion in a Storage Ring 2 COSY as Spin Physics R&D Facility 3 Measurements: Horizontal Polarization 4 Measurements: Vertical Polarization 5 Conclusion

20 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY Conclusion Conclusion -Collaboration: search for light hadrons permanent EDM accelerator experiment aim for ultimate precision conventional accelerator utilize polarization as diagnostic tool, examples: horizontal polarization: spin tune measurements as high precision tool established observation time for horizontal polarization pushed towards 1000 s mark vertical polarization: precision spin manipulation with minimal beam disturbance resonance strength determination by means of frequency measurement [ talk by A. Lehrach]

21 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY Spares Content 1 Spin Motion in a Storage Ring 2 COSY as Spin Physics R&D Facility 3 Measurements: Horizontal Polarization 4 Measurements: Vertical Polarization 5 Conclusion

22 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY Spares Spin Tune per Time Bin use RF flipper to rotate polarization in horizontal plane detector signal: N up, down (t) 1 ± sin(2πf S t + φ) f S γg f rev = 120 khz, but event rate only 5 khz detector event only every 25th oscillation period [J. Pretz, JEDI Collaboration]

22 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY Spares Spin Tune per Time Bin use RF flipper to rotate polarization in horizontal plane detector signal: N up, down (t) 1 ± sin(2πf S t + φ) f S γg f rev = 120 khz, but event rate only 5 khz detector event only every 25th oscillation period time stamps t map all events of macroscopic bin into one assumed oscillation period T s t = mod (t, T s ) [J. Pretz, JEDI Collaboration]

23 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY Spares Spin Tune per Time Bin, cont. 1 timestamps t map all events of macroscopic bin into one assumed oscillation period T s t = mod (t, T s ) 2 calculate asymmetries in one time period and fit oscillation 3 extract amplitude ɛ polarization from fit 0.4 asymmertry 0.2 0-0.2 ɛ(φ s ) = ɛ sin(φs + φ) φ s = 2π t Ts -0.4 0 1 2 3 4 5 6 ϕ [rad] s [D. Eversmann, JEDI Collaboration]

23 s.mey@fz-juelich.de High Precision Spin Manipulation at COSY Spares Spin Tune per Time Bin, cont. 1 timestamps t map all events of macroscopic bin into one assumed oscillation period T s t = mod (t, T s ) 2 calculate asymmetries in one time period and fit oscillation 3 extract amplitude ɛ polarization from fit 4 vary value of T s, repeat 5 best spin tune manifests as maximum in spectrum of ν s = 2π T sf rev 0.4 0.3 asymmertry 0.2 0-0.2 ɛ(φ s ) = ɛ sin(φs + φ) φ s = 2π t Ts amplitude 0.2 0.1-0.4 0 1 2 3 4 5 6 ϕ [rad] s 0.0 0.160970 0.160975 0.160980 0.160985 spin tune ν0 s [D. Eversmann, JEDI Collaboration]