Dynamic aperture study at the VEPP-4M storage ring

Киселев, В. А.; Levichev, E.; Sajaev, V.; Smaluk, Victor

doi:10.1109/pac.1997.750728

Cited by 5 publications

(3 citation statements)

References 2 publications

(1 reference statement)

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“…All particles beyond the free dynamic aperture are lost. The free dynamic aperture is determined by fitting an error function to the measured losses over kick amplitudes as described in [38][39][40].…”

Section: Evaluation Of Forced Dynamic Aperture From Beam Intensitmentioning

confidence: 99%

First experimental demonstration of forced dynamic aperture measurements with LHC ac dipoles

Carlier

Tomás

Maclean

et al. 2019

Phys. Rev. Accel. Beams

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Diagnostics of nonlinear beam dynamics has become more important for the LHC as it advances into increasingly challenging regimes of operation, as well as for the High Luminosity LHC where machine nonlinearities will have a significantly larger impact. Limitations of traditional excitation methods at top energy, in particular due to machine protection, have pushed the development of safe alternative methods using ac dipoles to characterize the nonlinear content of the LHC. One of the methods that has been proposed is the dynamic aperture under forced oscillation of ac dipoles. This new observable has the potential to help characterize relative changes in the nonlinear content of the machine, improve the understanding of the nonlinear models by comparing to simulations, validate nonlinear optics corrections, and give a qualitative lower bound estimate on the free dynamic aperture. This paper presents the first experimental demonstration of forced dynamic aperture measurements under forced oscillations performed using the LHC ac dipoles, and discusses the benefits of forced dynamic aperture measurements in circular colliders.

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Section: Evaluation Of Forced Dynamic Aperture From Beam Intensitmentioning

confidence: 99%

First experimental demonstration of forced dynamic aperture measurements with LHC ac dipoles

Carlier

Tomás

Maclean

et al. 2019

Phys. Rev. Accel. Beams

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“…Estimation of impedances for long-running accelerators, vacuum chambers of which have a big number of inhomogeneities, is rather difficult and labour-consuming problem. In such cases, experimental study of impedances is carried out by analysis of beam motion [14][15][16][17].…”

Section: Jinst 7 P01007mentioning

confidence: 99%

“…For example, the dynamic aperture of VEPP-4M was limited by strong final-focus sextupoles making a large contribution to the driving term of third-order nonlinear resonance. To increase the dynamic aperture, we had to reduce twice the strength of these sextupoles [34].…”

Section: Jinst 7 P01007mentioning

confidence: 99%

Feedback for suppression of single-bunch transverse instability in electron-positron storage rings

et al. 2012

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Transverse head-tail instability is a severe limitation of a single-bunch beam current in circular accelerators. Applicability and efficiency of feedbacks for suppression of the instability is analyzed. Both chromatic and nonlinear effects have been taken into account to understand the processes of excitation and damping of the instability. Analytical estimations are compared with the results of experiments and numerical simulations. A feedback system has been developed, installed and commissioned at the VEPP-4M electron-positron collider. An original scheme of the kicker powering has been developed to provide the necessary performance with minimal expenses. Real-time digital data processing performed by a code running in an FPGA module provides high efficiency and flexibility of the system. During the system commissioning, a more than threefold increase of intensity of the VEPP-4M single-bunch beam has been achieved.

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