Emittance sharing and exchange driven by linear betatron coupling in circular accelerators

Franchi, A.; Métral, E.; Tomás, Rogelio

doi:10.1103/physrevstab.10.064003

Cited by 20 publications

(30 citation statements)

References 7 publications

(9 reference statements)

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“…This is the typical case of hadron circular accelerators with the two betatron tunes having the same integer part, already treated in Ref. [20].…”

Section: B Rms Projected Emittancesmentioning

confidence: 94%

“…This is done through the two coupling RDTs f 1001 and f 1010 of Refs. [17,20]. Both are measurable and their knowledge provides a direct evaluation of both the real RMS and the equilibrium emittance (in absence of synchrobetatron coupling).…”

Section: Introductionmentioning

confidence: 99%

“…In Ref. [20] the focus was given to hadron beams near the difference resonance, where the emittance evolution is defined by both the coupling RDT f 1001 and the initial emittances r0 . In lepton machines with radiation damping and diffusion, the role of initial emittance is somehow replaced by the equilibrium emittances, that depend on the RDTs too.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Vertical emittance reduction and preservation in electron storage rings via resonance driving terms correction

Franchi

Farvacque

Chavanne

et al. 2011

Phys. Rev. ST Accel. Beams

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In this paper the influence of betatron coupling on the transverse beam emittances is described using the resonance driving terms formalism. Betatron coupling and vertical dispersion generated by magnetic and installation errors are major sources of vertical emittance. A new scheme for minimizing the latter is presented here, together with results from measurements carried out in 2010 at the ESRF electron storage ring, which provided vertical emittance of about 4.4 pm, a record low for this machine. Two schemes for the automatic compensation of coupling introduced by insertion devices are also presented with results from the first implementation tests. This paper is also an attempt to clarify the various definitions and meanings of vertical emittance in the presence of coupling.

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“…This is the typical case of hadron circular accelerators with the two betatron tunes having the same integer part, already treated in Ref. [20].…”

Section: B Rms Projected Emittancesmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Vertical emittance reduction and preservation in electron storage rings via resonance driving terms correction

Franchi

Farvacque

Chavanne

et al. 2011

Phys. Rev. ST Accel. Beams

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“…In the Appendix of Ref. [26] the complete Lie series of Eq. (A64) was computed in presence of betatron coupling, i.e.…”

Section: Appendix C: Quadrupole Errors and Tune-line Amplitudementioning

confidence: 99%

First simultaneous measurement of sextupolar and octupolar resonance driving terms in a circular accelerator from turn-by-turn beam position monitor data

Franchi

Farvacque

Ewald

et al. 2014

Phys. Rev. ST Accel. Beams

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Beam lifetime in storage rings and colliders is affected by , among other effects, lattice nonlinearities. Their control are of great benefit to the dynamic aperture of an accelerator, whose enlargement leads in general to more efficient injection and longer lifetime. This article describes a procedure to evaluate and correct unwanted nonlinearities by using turn-by-turn beam position monitor data, which is an evolution of previous works on the resonance driving terms (RDTs). Effective sextupole magnetic errors and tilts at the ESRF electron storage ring are evaluated and corrected (when possible) by using this technique. For the first time, also octupolar RDTs could be measured and used to define an octupolar model for the main quadrupoles. Most of the deviations from the model observed in the sextupolar RDTs of the ESRF storage ring turned out to be generated by focusing errors rather than by sextupole errors. These results could be achieved thanks to new analytical formulas describing the harmonic content of the nonlinear betatron motion to the second order. For the first time, RDTs have been also used for beam-based calibration of individual sextupole magnets. They also proved to be a powerful tool in predicting faulty magnets and in validating magnetic models. This technique provides also a figure of merit for a self-assessment of the reliability of the data analysis.

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“…destabilising one or two planes, as it was believed to be the case with the Batman instability of the HERA proton ring [163]). Furthermore, one has also to be careful with linear coupling as it modifies the transverse emittances [164,165].…”

Section: A Sacherer's and Laclare's Approachesmentioning

confidence: 99%

Beam Instabilities in Hadron Synchrotrons

Métral

Argyropoulos

Bartosik

et al. 2016

IEEE Trans. Nucl. Sci.

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Abstract-Beam instabilities cover a wide range of effects in particle accelerators and they have been the subject of intense research for several decades. As the machines performance was pushed new mechanisms were revealed and nowadays the challenge consists in studying the interplays between all this intricate phenomena, as it is very often not possible to treat the different effects separately. The aim of this paper is to review the main mechanisms, discussing in particular the recent developments of beam instability theories and simulations.

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Emittance sharing and exchange driven by linear betatron coupling in circular accelerators

Cited by 20 publications

References 7 publications

Vertical emittance reduction and preservation in electron storage rings via resonance driving terms correction

Vertical emittance reduction and preservation in electron storage rings via resonance driving terms correction

First simultaneous measurement of sextupolar and octupolar resonance driving terms in a circular accelerator from turn-by-turn beam position monitor data

Beam Instabilities in Hadron Synchrotrons

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