Measuring the polarization of a rapidly precessing deuteron beam

Bagdasarian, Z.; Bertelli, Susanna; Chiladze, D.; Ciullo, G.; Dietrich, J.; Dymov, S.; Eversmann, D.; Fanourakis, G.; Gaisser, M.; Gebel, R.; Gou, B.; Guidoboni, Greta; Hejny, V.; Kacharava, A.; Kamerdzhiev, V.; Lehrach, A.; Lenisa, P.; Lorentz, B.; Magallanes, L.; Maier, R.; Mchedlishvili, D.; Morse, W. M.; Nass, A.; Oellers, D.; Pesce, A.; Prasuhn, D.; Pretz, J.; Rathmann, F.; Shmakova, V.; Semertzidis, Yannis K.; Stephenson, E. J.; Stockhorst, H.; Ströher, H.; Talman, R.; Engblom, P. Thörngren; Valdau, Yu.; Weidemann, Christian; Wüstner, P.

doi:10.1103/physrevstab.17.052803

Cited by 49 publications

(39 citation statements)

References 9 publications

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“…This feature is present to a lesser extent in the model time dependence of Ref. [7], also created for lower beam currents. In other cases, the half-life may be appropriate (see Fig.…”

Section: Figmentioning

confidence: 81%

“…In a second pass through the data, the spin tune was fixed at an average value among all the time bins (sometimes with a smooth trend added) and the analysis repeated. With this constraint, the new set of phases had a smooth time dependence so long as the IPP magnitude was not close to zero [7].…”

Section: Event Time Marking Chromaticity Measurement and Runnimentioning

confidence: 99%

“…Section II contains a brief summary of transverse oscillations and their connection to chromaticity. In Section III we turn to the explanation of the experiment, beginning with a review of the time-marking system used to measure the IPP [7] and a description of the context provided by the map of chromaticity values for the data taking plan. The results are shown in Section IV along with the constraints on their interpretation.…”

Section: Introductionmentioning

confidence: 99%

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Connection between zero chromaticity and long in-plane polarization lifetime in a magnetic storage ring

Guidoboni¹,

Stephenson²,

Wrońska³

et al. 2018

Phys. Rev. Accel. Beams

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In this paper, we demonstrate the connection between a magnetic storage ring with additional sextupole fields set so that the x and y chromaticities vanish and the maximizing of the lifetime of in-plane polarization (IPP) for a 0.97-GeV/c deuteron beam. The IPP magnitude was measured by continuously monitoring the down-up scattering asymmetry (sensitive to sideways polarization) in an in-beam, carbon-target polarimeter and unfolding the precession of the IPP due to the magnetic anomaly of the deuteron. The optimum operating conditions for a long IPP lifetime were made by scanning the field of the storage ring sextupole magnet families while observing the rate of IPP loss during storage of the beam. The beam was bunched and electron cooled. The IPP losses appear to arise from the change of the orbit circumference, and consequently the particle speed and spin tune, due to the transverse betatron oscillations of individual particles in the beam. The effects of these changes are canceled by an appropriate sextupole field setting.

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“…This feature is present to a lesser extent in the model time dependence of Ref. [7], also created for lower beam currents. In other cases, the half-life may be appropriate (see Fig.…”

Section: Figmentioning

confidence: 81%

Section: Event Time Marking Chromaticity Measurement and Runnimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Connection between zero chromaticity and long in-plane polarization lifetime in a magnetic storage ring

Guidoboni¹,

Stephenson²,

Wrońska³

et al. 2018

Phys. Rev. Accel. Beams

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“…Instead, at p = 0.97 GeV/c, the in-plane polarization (produced through the action of an rf solenoid operating on the 1 -Gγ spin resonance) rotates at about 120 kHz. By marking each event with the clock time when it occurred, it is possible to unfold this precession and look for a down-up asymmetry in the polarimeter whenever the polarization axis points along the radial (sideways) direction in the ring [5]. The clock operated with a time step of 92.59 ps.…”

Section: Measuring In-plane Polarizationmentioning

confidence: 99%

Deuteron polarimeter developments for a storage ring electric dipole moment search

Stephenson¹

2016

Proceedings of XVIth International Workshop in Polarized Sources, Targets, and Polarimetry — PoS(PSTP2015)

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This talk will summarize progress made at the Forschungszentrum Jülich COSY ring on deuteron beam polarimetry for a storage ring search for an electric dipole moment (EDM). Tests have demonstrated the feasibility of using thick carbon targets for highly efficient and continuous observation of the stored beam polarization. After calibration of the sensitivity to geometric misalignments and pileup contributions to the trigger rates, it is possible to correct cross-ratio polarization measurements in real time to levels below one part in 10 5 . By marking each event with the clock time, the horizontal plane precession of the polarization in the ring magnets may be unfolded, yielding access to the magnitude of the horizontal polarization as a function of time. Accurate values require attention to biases from searches for the correct precession rate and false enhancements to the magnitude at low polarizations. This technique facilitates studies of various means to extend the unstable horizontal plane polarization lifetime using bunching, electron cooling, sextupole correction fields, and beam current management with the result that polarization lifetimes now exceed hundreds of seconds. Future plans include feedback to control the polarization precession rate and phase (in preparation for maintaining the polarization parallel to the velocity in a future EDM ring), database measurements to enable better polarimeter engineering, and the extension of these studies to protons.

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“…An analytical model is derived, which is compared to the data. The work is based on earlier publications; it makes use of the 1000 s spin coherence time at the Cooler Synchrotron (COSY) [1], measurements of the fast (120 kHz) precession in the horizontal plane [2,3] and a polarization feedback system, which is used to select the initial conditions for the measurements presented here [4].…”

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confidence: 99%