First Observation of the Exchange of Transverse and Longitudinal Emittances

Ruan, J.; Johnson, A. S.; Lumpkin, A.H.; Thurman‐Keup, R.; Edwards, H.; Fliller, R.; Koeth, T.; Sun, Yipeng

doi:10.1103/physrevlett.106.244801

Cited by 31 publications

(30 citation statements)

References 8 publications

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“…8, but the longitudinal-emittance product is smaller than when using the minimum bunch-length settings. Subsequent tests with the crystal screen in XS4 support this value [21]. The vertical emittance growth was about 20% even with the 1-sigma errors applied, perhaps due to some coupling between the x-y planes.…”

Section: Emittance-exchange Resultsmentioning

confidence: 66%

“…The lowest divergence numbers result from large fractional corrections for the camera-resolution term so we ran in the solenoidal-current regime where the errors were fractionally smaller. The upgraded X6 station with a larger drift distance from the X3 station, and hence larger divergence-related effects, will ameliorate this issue as will be separately reported [21]. …”

Section: Resultsmentioning

confidence: 93%

“…[7] in which no projected profile size corrections were made and no diagnostics upgrades had been done). Subsequently, more recent measurements led to the long-sought observations of nearly ideal one-to-one exchanges with little evidence of coupling into the y plane [21]. …”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Upgrades of beam diagnostics with application to emittance-exchange experiments

Lumpkin

Johnson

Ruan

et al. 2011

Phys. Rev. ST Accel. Beams

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The possibility of using electron-beam phase-space manipulations to support a free-electron laser accelerator design optimization has motivated our research. An ongoing program demonstrating the exchange of transverse horizontal and longitudinal emittances at the Fermilab A0 photoinjector has benefited recently from the upgrade of several of the key diagnostics stations. Accurate measurements of these properties upstream and downstream of the exchanger beam line are needed. Improvements in the screen resolution term and reduced impact of the optical system's depth of focus by using YAG:Ce single crystals normal to the beam direction will be described. The requirement to measure small energy spreads (< 10 keV) in the spectrometer and the exchange process which resulted in bunch lengths less than 800 fs led to other diagnostics performance adjustments and upgrades as well. Application of these diagnostics in demonstrating the exchange of transverse (x) and longitudinal phase spaces is also reported.

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Section: Emittance-exchange Resultsmentioning

confidence: 66%

Section: Resultsmentioning

confidence: 93%

See 1 more Smart Citation

Upgrades of beam diagnostics with application to emittance-exchange experiments

Lumpkin

Johnson

Ruan

et al. 2011

Phys. Rev. ST Accel. Beams

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“…The focus of this paper is the relatively new technique based on an emittance exchange between the transverse and longitudinal phase spaces, which does not need the beam to be energy modulated and thus can be used for high brightness beams [27][28][29][30][31]. The EEX optics were initially proposed in application to the free electron laser for transverse emittance reduction in an electron beam with a smaller longitudinal emittance [29] and first verified experimentally at the Fermilab A0 Photoinjector [32]. In general, the EEX is a device which swaps longitudinal beam emittance with one of the transverse emittances, leaving the third emittance unchanged.…”

Section: Introductionmentioning

confidence: 99%

Design of an emittance exchanger for production of special shapes of the electron beam current

Shchegolkov

Simakov

2014

Phys. Rev. ST Accel. Beams

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Recently, considerable attention has been focused on electron beam current profile shaping by means of a transverse beam mask followed by an emittance exchanger (EEX). This setup can transform a transverse particle distribution into a longitudinal particle distribution. We investigate the EEX technique with application to production of a double triangular drive and a trapezoidal main bunches for high transformer ratio, high brightness dielectric wakefield accelerators. We perform numerical optimization of two realistic configurations: a double dogleg and a chicane. In this paper we report sample designs and discuss the effects of the beam line nonlinearities, beam space charge, and coherent synchrotron radiation on a current profile of the output beam.

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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].…”

mentioning

confidence: 99%

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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First Observation of the Exchange of Transverse and Longitudinal Emittances

Cited by 31 publications

References 8 publications

Upgrades of beam diagnostics with application to emittance-exchange experiments

Upgrades of beam diagnostics with application to emittance-exchange experiments

Design of an emittance exchanger for production of special shapes of the electron beam current

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

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