Keyword: polarization
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TUPOA28 Feasibility of OTR Imaging for Laser-Driven Plasma Accelerator Electron-Beam Diagnostics ion, electron, laser, plasma 345
  • A.H. Lumpkin
    Fermilab, Batavia, Illinois, USA
  • M. Downer
    The University of Texas at Austin, Austin, Texas, USA
  • D.W. Rule
    Private Address, Silver Spring, USA
  Funding: * Work at Fermilab partly supported by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. DoE. ** Work at the Univ. of Texas supported by DoE grant DE-SC0011617.
Recent measurements of betatron x-ray emission from quasi-monoenergetic electrons accelerating to 500 MeV within a laser plasma accelerator (LPA) enabled estimates of normalized transverse emittance well below 1 mm-mrad and divergences of order 1/gamma [1]. Such unprecedented LPA beam parameters can, in principle, be addressed by utilizing the properties of linearly polarized optical transition radiation (OTR) that provide additional beam parameter sensitivity. We propose a set of complementary measurements of beam size and divergence with near-field and far-field OTR imaging, respectively, on LPA electron beams ranging in energy from 100 MeV [2] to 2 GeV [3]. The feasibility is supported by analytical modeling for beam size sensitivity and divergence sensitivity. In the latter case, the calculations indicate that the parallel polarization component of the far-field OTR pattern is sensitive to divergences from 0.1 to 0.4 mrad (σ) at 2 GeV, and it is similarly sensitive to divergences from 1 to 5 mrad (σ) at 100 MeV. We anticipate the signal levels from charges of 100 pC will require a 16-bit cooled CCD camera. Other practical challenges in the LPA will also be discussed.
1.G. R. Plateau et al., Phys. Rev. Lett. 109, 064802 (2012).
2.Hai-EnTsai, Chih-Hao Pai, and M.C. Downer, AIP Proc. 1507, 330 (2012)
3.Xiaoming Wang et al., Nature Communications 4,1988(2013).
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TUPOB30 Spin Flipping System in the JLEIC Collider Ring ion, collider, controls, solenoid 558
  • V.S. Morozov, Y.S. Derbenev, F. Lin, Y. Zhang
    JLab, Newport News, Virginia, USA
  • Y. Filatov
    MIPT, Dolgoprudniy, Moscow Region, Russia
  • A.M. Kondratenko, M.A. Kondratenko
    Science and Technique Laboratory Zaryad, Novosibirsk, Russia
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contracts No. DE-AC05-06OR23177 and DE-AC02-06CH11357.
The figure-8 JLEIC collider ring opens wide possibilities for manipulating proton and deuteron spin directions during an experiment. Using 3D spin rotators, one can, at the same time, efficiently control the polarization direction as well as the spin tune value. The 3D spin rotators allow one to arrange a system for reversals of the spin direction in all beam bunches during an experiment, i.e. a spin-flipping system. To preserve the polarization, one has to satisfy the condition of adiabatic change of the spin direction. When adjusting the polarization direction, one can stabilize the spin tune value, which completely eliminates resonant beam depolarization during the spin manipulation process. We provide the results of numerical modeling of a spin-flipping system in the JLEIC ion collider ring. The presented results demonstrate the feasibility of organizing a spin-flipping system using a 3D rota-tor. The figure-8 JLEIC collider provides a unique capability of doing high-precision experiments with polarized ion beams.
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TUPOB41 Bi-Complex Toolbox Applied to Gyromagnetic Beam Break-Up ion, dipole, experiment, linac 585
  • A.V. Smirnov
    RadiaBeam, Santa Monica, California, USA
  Transverse instability of a multi-bunch beam in the presence of a longitudinal magnetostatic field and hybrid dipole modes is considered analytically within a single-section model. It incorporates resonant interaction with beam harmonics and eigenmodes, degenerated waves of different polarizations, and the Lorentz RF force contribution. The analysis is performed in a very compact form using a bi-complex i,j-space including four-component collective frequency of the instability. Rotating polarization of the collective field is determined by ImiImj part of the bi-complex collective frequency in agreement with available data. The other three components represent detuning of the collective frequency ReiRej, the left-hand, and right-hand increments ImiRej±ReiImj of the gyro-magnetic BBU effect. The scalar hyper-complex toolbox can be applied to designing of non-ferrite non-reciprocal devices, spin transport, and for characterization of complex transverse dynamics in gyro-devices such as Gyro-TWTs.  
poster icon Poster TUPOB41 [0.526 MB]  
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WEA2IO01 Calculating Spin Lifetime ion, resonance, lattice, synchrotron 667
  • V.H. Ranjbar
    BNL, Upton, Long Island, New York, USA
  Funding: Work supported by the US Department of Energy under contract number DE-SC0012704.
We have extended a lattice independent code to integrate the Thomas-BMT equation over 2 hours of beam time in the presence of two orthogonal Siberian snakes. In tandem to this we have recast the Thomas-BMT equation in the presences of longitudinal dynamics, into the parametric resonance formalism recently developed to understand overlapping spin resonances *
* V. H. Ranjbar, "Approximations for crossing two nearby spin
resonances," Phys. Rev. ST Accel. Beams 18, no. 1, 014001
(2015). doi:10.1103/PhysRevSTAB.18.014001
slides icon Slides WEA2IO01 [2.252 MB]  
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THPOA26 Analysis of the Transport of Muon Polarization for the Fermilab G-2 Muon Experiment ion, proton, experiment, target 1158
  • D. Stratakis, K.E. Badgley, M.E. Convery, J.P. Morgan, M.J. Syphers, J.C.T. Thangaraj
    Fermilab, Batavia, Illinois, USA
  • J.D. Crnkovic, W. Morse
    BNL, Upton, Long Island, New York, USA
  • M.J. Syphers
    Northern Illinois University, DeKalb, Illinois, USA
  Funding: Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy.
The Muon g-2 experiment at Fermilab aims to measure the anomalous magnetic moment of the muon to a precision of 140 ppb ─ a fourfold improvement over the 540 ppb precision obtained in BNL experiment E821. Obtaining this precision requires controlling total systematic errors at the 100 ppb level. One form of systematic error on the measurement of the anomalous magnetic moment occurs when the muon beam injected and stored in the ring has a correlation between the muon's spin direction and its momentum. In this paper, we first analyze the creation and transport of muon polarization from the production target to the Muon g-2 storage ring. Then, we detail the spin-momentum and spin-orbit correlations and estimate their impact on the final measurement. Finally, we outline mitigation strategies that could potentially circumvent this problem.
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FRA1CO06 Measurement of Coherent Transition Radiation Using Interferometer and Photoconductive Antenna ion, electron, laser, linac 1279
  • K. Kan, M. Gohdo, T. Kondoh, I. Nozawa, J. Yang, Y. Yoshida
    ISIR, Osaka, Japan
  Ultrashort electron beams are essential for light sources and time-resolved measurements. Electron beams can emit terahertz (THz) pulses using coherent transition radiation (CTR). Michelson interferometer* is one of candidates for analyzing the pulse width of an electron beam based on frequency-domain analysis. Recently, electron beam measurement using a photoconductive antenna (PCA)** based on time-domain analysis has been investigated. In this presentation, measurement of femtosecond electron beam with 35 MeV energy and < 1 nC from a photocathode based linac will be reported. Frequency- and time- domain analysis of THz pulse of CTR by combining the interferometer and PCA will be carried out.
* I. Nozawa, K. Kan et al., Phys. Rev. ST Accel. Beams 17, 072803 (2014).
** K. Kan et al., Appl. Phys. Lett. 102, 221118 (2013).
slides icon Slides FRA1CO06 [2.334 MB]  
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