Single-knob beam line for transverse emittance partitioning

Xiao, Chen; Kester, O.; Groening, L.; Leibrock, H.; Maier, M.; Rottländer, Peter

doi:10.1103/physrevstab.16.044201

Cited by 26 publications

(40 citation statements)

References 17 publications

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“…The theoretical framework and analytical tools developed in the present study are also expected to be effective for the current theoretical and experimental investigations of emittance exchange technologies. [44][45][46][47][48][49][50] …”

Section: Discussionmentioning

confidence: 99%

Spectral and structural stability properties of charged particle dynamics in coupled latticesa)

et al. 2015

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It has been realized in recent years that coupled focusing lattices in accelerators and storage rings have significant advantages over conventional uncoupled focusing lattices, especially for high-intensity charged particle beams. A theoretical framework and associated tools for analyzing the spectral and structural stability properties of coupled lattices are formulated in this paper, based on the recently developed generalized Courant-Snyder theory for coupled lattices. It is shown that for periodic coupled lattices that are spectrally and structurally stable, the matrix envelope equation must admit matched solutions. Using the technique of normal form and pre-Iwasawa decomposition, a new method is developed to replace the (inefficient) shooting method for finding matched solutions for the matrix envelope equation. Stability properties of a continuously rotating quadrupole lattice are investigated. The Krein collision process for destabilization of the lattice is demonstrated. V C 2015 AIP Publishing LLC. [http://dx

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Section: Discussionmentioning

confidence: 99%

Spectral and structural stability properties of charged particle dynamics in coupled latticesa)

et al. 2015

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“…It can be shown that the two eigenemittances are given by (EMTEX) [11,12]. For the RTFB transformation experiment, κ 0 is given by κ 0 = Bs 2(Bρ)c , where B s and (Bρ) c are the solenoidal magnetic field and beam rigidity at the cathode, respectively.…”

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“…[11]. The focusing coefficients of the skew-quadrupoles are kept fixed at the values used to decouple the beam produced by a solenoidal field of 1.0 T, with the conditions of zero space-charge and zero acceleration.…”

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“…The roundto-flat beam transformation [2][3][4][5][6] and the transverse-to-longitudinal emittance exchange [7][8][9][10] have been investigated for electron injectors. The generation of flat hadron beams has recently drawn significant attention in the context of optimizing emittance budgets in heavy ion synchrotrons [11,12], and improving space-charge and beam-beam luminosity limitations in colliders [13]. For muon ionization cooling, special arrangements of solenoidal mangets are employed to achieve six-dimensional emittance reduction [14,15].…”

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confidence: 99%

“…For the EMTEX experiment, κ 0 = (Bρ) in (Bρ)out − 1 Bs 2(Bρ) in , where (Bρ) in and (Bρ) out are the beam rigidity before and after the stripping foil, respectively. To remove the correlation in Σ 0 , a beam-line constructed by three skew-quadrupoles is often used [2,11].…”

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Generalized Kapchinskij-Vladimirskij Distribution and Beam Matrix for Phase-Space Manipulations of High-Intensity Beams

et al. 2016

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In an uncoupled linear lattice system, the Kapchinskij-Vladimirskij (KV) distribution, formulated on the basis of the single-particle Courant-Snyder (CS) invariants, has served as a fundamental theoretical basis for the analyses of the equilibrium, stability, and transport properties of high-intensity beams for the past several decades. Recent applications of high-intensity beams, however, require beam phase-space manipulations by intentionally introducing strong coupling. In this Letter, we report the full generalization of the KV model by including all of the linear (both external and space-charge) coupling forces, beam energy variations, and arbitrary emittance partition, which all form essential elements for phase-space manipulations. The new generalized KV model yields spatially uniform density profiles and corresponding linear self-field forces as desired.The corresponding matrix envelope equations and beam matrix for the generalized KV model provide important new theoretical tools for the detailed design and analysis of high-intensity beam manipulations, for which previous theoretical models are not easily applicable.

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Collimation and decoupling of ECR source beams for brilliance optimization

Xiao

Groening

Kester

2014

Nuclear Instruments and Methods in Physics Research Section A:

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The four-dimensional transport of the transverse phase space of the extracted beam was calculated for the CAPRICE electron cyclotron resonance (ECR) ion source at GSI. The axial magnetic field adds an angular momentum to the extracted beam, resulting in a strongly x-y coupled beam. The report presents multi-particle tracking simulations, and the results illustrate that the beam brilliance can be improved by combination of multi-stage collimation with skew quadrupole decoupling. Quadrupole Collimation ChannelThe quadrupole collimation channel is placed behind the analyzing magnet in order to improve the beam brightness. An uncorrelated beam with desired Twiss parameters is assumed at the entrance of the quadrupole collimation channel being the periodic matched solution of the channel. Only particles in a defined phase space volume are transmitted through the entire channel, all other particles are stopped at the apertures along the channel. The magnetic quadrupole collimation channel has three cells including three identical magnetic quadrupole doublets and four fourjaw slits. For efficient and flexible collimation, each cell is set to cause a phase space rotation of 45 degree and multiple cells with overall phase advance rotation larger than 90 degree (145 degree in this channel). Four successive four-jaw slits are used for multi-stage collimation with the phase space rotation in between [1]. Skew quadrupole decoupling sectionAfter charge-to-mass selection, two normal quadrupole doublets are used to match the analyzed beam into the quadrupole collimation channel. The quadrupole collimation channel, which consists of three normal quadrupole doublets with the same gradient but alternating sign are used to carry out the multiple-stage phase space rotation. The decoupling section comprises two normal quadrupole doublets and one skew quadrupole triplet, and their gradients are optimized by a numerical routine to remove the inter-plane correlations, thus minimizing the product of the horizontal and vertical rms emittances [2]. * Work supported by the Helmholtz International Center for FAIR and the Bundesministerium für Bildung und Forschung.† c.xiao@gsi.de Collimation and decoupling simulationIn general, an ECR ion source beam possesses a large beam size and divergence. Therefore, higher order effects (aberrations) can not be avoided inside the solenoid. If the particle deviates from the center of the solenoid, it feels a non-linear force and the non-linear force causes the rms emittances and eigen-emittances to grow. Once the beam enters the analyzing magnet the horizontal rms emittance starts to increase gradually, but the vertical rms emittance is not changed. After charge selection, if the collimators are not adopted to cut particles, the rms emittances and eigen-emittances are almost constant until the first skew quadrupole. If the collimators are adopted, utilization of collimators stepwise decreases the rms emittances and eigen-emittances in the matching section. Inside of the skew quadrupole triplet, r...

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Single-knob beam line for transverse emittance partitioning

Cited by 26 publications

References 17 publications

Spectral and structural stability properties of charged particle dynamics in coupled latticesa)

Spectral and structural stability properties of charged particle dynamics in coupled latticesa)

Generalized Kapchinskij-Vladimirskij Distribution and Beam Matrix for Phase-Space Manipulations of High-Intensity Beams

Collimation and decoupling of ECR source beams for brilliance optimization

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