Steering and Focusing Effects in TESLA Cavity due to High Order Mode and Input Couplers

Piot, Philippe; Dohlus, M.; Flöttmann, Klaus; Marx, M.; Wipf, Susan G.

doi:10.1109/pac.2005.1591742

Cited by 4 publications

(4 citation statements)

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“…It should however be noted that the time dependence of these effects, especially of the dipole kick, can lead to significant emittance increase via a head-tail effect where different temporal slice within the bunch experience a time-varying kick resulting in a dilution of transverse emittance. Such an effect is especially important when low-emittance lowenergy beams are being accelerated in a string of cavities [7,9,10].…”

Section: Numerical Analysismentioning

confidence: 99%

“…Such a cavity is a 9-cell standing-wave accelerating structure operating in the T M 010,π mode. The transverse beam dynamics associated to such a cavity has been extensively explored over the last decade and focused essentially on numerical simulations of single-bunch emittance dilution due to the field asymmetries [7][8][9][10] and multibunch effects due to trapped modes [11]. Most recently, experiments aimed at characterizing the transverse beam dynamics in this type of SRF cavity were performed [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

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Analysis and measurement of the transfer matrix of a 9-cell, 1.3-GHz superconducting cavity

Halavanau

Eddy

Edstrom

et al. 2017

Phys. Rev. Accel. Beams

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Superconducting linacs are capable of producing intense, stable, high-quality electron beams that have found widespread applications in science and industry. The 9-cell 1.3-GHz superconducting standing-wave accelerating RF cavity originally developed for e + /e − linear-collider applications [B. Aunes, et al. Phys. Rev. ST Accel. Beams 3, 092001 (2000)] has been broadly employed in various superconducting-linac designs. In this paper we discuss the transfer matrix of such a cavity and present its measurement performed at the Fermilab Accelerator Science and Technology (FAST) facility. The experimental results are found to be in agreement with analytical calculations and numerical simulations.

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Section: Numerical Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Analysis and measurement of the transfer matrix of a 9-cell, 1.3-GHz superconducting cavity

Halavanau

Eddy

Edstrom

et al. 2017

Phys. Rev. Accel. Beams

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“…Couplers break the axial symmetry of the cavity [9]. Their impact on the beam is illustrated in Fig.…”

Section: Introductionmentioning

confidence: 99%

Detuning related coupler kick variation of a superconducting nine-cell 1.3 GHz cavity

Hellert

Dohlus

2018

Phys. Rev. Accel. Beams

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Superconducting TESLA-type cavities are widely used to accelerate electrons in long bunch trains, such as in high repetition rate free electron lasers. The TESLA cavity is equipped with two higher order mode couplers and a fundamental power coupler (FPC), which break the axial symmetry of the cavity. The passing electrons therefore experience axially asymmetrical coupler kicks, which depend on the transverse beam position at the couplers and the rf phase. The resulting emittance dilution has been studied in detail in the literature. However, the kick induced by the FPC depends explicitly on the ratio of the forward to the backward traveling waves at the coupler, which has received little attention. The intention of this paper is to present the concept of discrete coupler kicks with a novel approach of separating the field disturbances related to the standing wave and a reflection dependent part. Particular attention is directed to the role of the penetration depth of the FPC antenna, which determines the loaded quality factor of the cavity. The developed beam transport model is compared to dedicated experiments at FLASH and European XFEL. Both the observed transverse coupling and detuning related coupler kick variations are in good agreement with the model. Finally, the expected trajectory variations due to coupler kick variations at European XFEL are investigated and results of numerical studies are presented.

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“…It should however be noted that the time dependence of these effects, especially of the dipole kick, can lead to significant emittance increase via a head-tail effect where different temporal slice within the bunch experience a time-varying kick resulting in a dilution of transverse emittance. Such an effect is especially important when low-emittance low-energy beams are being accelerated in a string of cavities[25,27,3].…”

mentioning

confidence: 99%

Electron Beam Shaping and Its Applications

Halavanau¹

2018

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Transverse and longitudinal electron beam shaping is a crucial part of high-brightness electron accelerator operations. In this dissertation, we report on the corresponding beam dynamics research conducted at Fermilab Accelerator Science and Technology facility (FAST) and Argonne Wakefield Accelerator (AWA). We demonstrate an experimental method for spatial laser and electron beam shaping using microlens arrays (MLAs) at a photoinjector facility. Such a setup was built at AWA and resulted in transverse emittance reduction by a factor of 2. We present transverse emittance partitioning methods that were recently employed at FAST facility. A strongly coupled electron beam was generated in an axial magnetic field and accelerated in 1.3 GHz SRF cavities to 34 MeV. It was then decoupled in Round-To-Flat beam transformer and beams with emittance asymmetry ratio of 100 were generated. We introduce the new methods of measuring electron beam canonical angular momentum, beam transformer optimization and beam image analysis. We also describe a potential longitudinal space-charge amplifier setup for FAST high-energy beamline. As an outcome, a broadband partially coherent radiation in the UV range could be generated.

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Steering and Focusing Effects in TESLA Cavity due to High Order Mode and Input Couplers

Cited by 4 publications

References 1 publication

Analysis and measurement of the transfer matrix of a 9-cell, 1.3-GHz superconducting cavity

Analysis and measurement of the transfer matrix of a 9-cell, 1.3-GHz superconducting cavity

Detuning related coupler kick variation of a superconducting nine-cell 1.3 GHz cavity

Electron Beam Shaping and Its Applications

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