Current-horn suppression for reduced coherent-synchrotron-radiation-induced emittance growth in strong bunch compression

T. K. Charles, D. M. Paganin, A. Latina, M. J. Boland, R. T. Dowd

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Control of coherent synchrotron radiation (CSR)-induced emittance growth is essential in linear accelerators designed to deliver very high brightness electron beams. Extreme current values at the head and tail of the electron bunch, resulting from strong bunch compression, are responsible for large CSR production leading to significant transverse projected emittance growth. The Linac Coherent Light Source (LCLS) truncates the head and tail current spikes which greatly improves free electron laser (FEL) performance. Here we consider the underlying dynamics that lead to formation of current spikes (also referred to as current horns), which has been identified as caustics forming in electron trajectories. We present a method to analytically determine conditions required to avoid the caustic formation and therefore prevent the current spikes from forming. These required conditions can be easily met, without increasing the transverse slice emittance, through inclusion of an octupole magnet in the middle of a bunch compressor.

Original languageEnglish
Article number030705
Number of pages14
JournalPhysical Review Accelerators and Beams
Volume20
Issue number3
DOIs
Publication statusPublished - 31 Mar 2017

Cite this

Charles, T. K. ; Paganin, D. M. ; Latina, A. ; Boland, M. J. ; Dowd, R. T. / Current-horn suppression for reduced coherent-synchrotron-radiation-induced emittance growth in strong bunch compression. In: Physical Review Accelerators and Beams. 2017 ; Vol. 20, No. 3.
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abstract = "Control of coherent synchrotron radiation (CSR)-induced emittance growth is essential in linear accelerators designed to deliver very high brightness electron beams. Extreme current values at the head and tail of the electron bunch, resulting from strong bunch compression, are responsible for large CSR production leading to significant transverse projected emittance growth. The Linac Coherent Light Source (LCLS) truncates the head and tail current spikes which greatly improves free electron laser (FEL) performance. Here we consider the underlying dynamics that lead to formation of current spikes (also referred to as current horns), which has been identified as caustics forming in electron trajectories. We present a method to analytically determine conditions required to avoid the caustic formation and therefore prevent the current spikes from forming. These required conditions can be easily met, without increasing the transverse slice emittance, through inclusion of an octupole magnet in the middle of a bunch compressor.",
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Current-horn suppression for reduced coherent-synchrotron-radiation-induced emittance growth in strong bunch compression. / Charles, T. K.; Paganin, D. M.; Latina, A.; Boland, M. J.; Dowd, R. T.

In: Physical Review Accelerators and Beams, Vol. 20, No. 3, 030705, 31.03.2017.

Research output: Contribution to journalArticleResearchpeer-review

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AU - Paganin, D. M.

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