Mechanical design and fabrication of the VHF-gun, the Berkeley normal-conducting continuous-wave high-brightness electron source

Wells, R.; Ghiorso, W.; Staples, J.; Huang, Ting-lei; Sannibale, F.; Kramasz, T.

doi:10.1063/1.4941836

Cited by 17 publications

(10 citation statements)

References 13 publications

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“…A detailed description of the VHF-Gun and of its characteristics can be found elsewhere [21,22], here, for the reader convenience, only the main relevant features of the gun are summarized. In the VHF-Gun scheme, the electron bunches are generated by laser-induced photoemission on high quantum efficiency (QE) semiconductor cathodes [24,29].…”

Section: The Vhf-gun and Apex The Advanced Photo-injector Experimentioning

confidence: 99%

“…A review and description of these different schemes can be found elsewhere [19]. Our group at the Lawrence Berkeley National Laboratory (LBNL) took a different route developing the very-high-frequency gun (VHF-Gun), a novelscheme lower-frequency room-temperature RF photo-gun [20][21][22][23][24] capable of continuous wave (CW) operation and optimized for the performance required by MHz-class Xray FELs [25,26]. The Advanced Photo-injector EXperiment (APEX), an injector test facility, was built at LBNL for demonstrating the VHF-Gun performance.…”

Section: Introductionmentioning

confidence: 99%

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High-brightness beam tests of the very high frequency gun at the Advanced Photo-injector EXperiment test facility at the Lawrence Berkeley National Laboratory

Sannibale

Filippetto

Qian

et al. 2019

Review of Scientific Instruments

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The very-high-frequency gun (VHF-Gun) is a new concept photo-injector developed and built at the Lawrence Berkeley National Laboratory (LBNL) for generating high-brightness electron beams capable of driving X-ray FELs at MHz-class repetition rates. The gun that purposely uses established and mature radiofrequency and mechanical technologies, has demonstrated over the last many years the capability of reliably operating in continuous wave mode at the design accelerating fields and required vacuum and mechanical performance. The results of VHF-Gun technology demonstration were reported elsewhere [F. Sannibale, et al., Phys. Rev. ST-Accel. and Beams 15, 103501 (2012)], here in this paper we provide and analyze examples of the experimental results of the first high-brightness beam tests performed at the Advanced Photo-injector EXperiment (APEX) test facility at LBNL that demonstrated the gun capability of delivering the beam quality required for driving high repetition rate X-ray FELs.

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Section: The Vhf-gun and Apex The Advanced Photo-injector Experimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

High-brightness beam tests of the very high frequency gun at the Advanced Photo-injector EXperiment test facility at the Lawrence Berkeley National Laboratory

Sannibale

Filippetto

Qian

et al. 2019

Review of Scientific Instruments

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“…Although the DC gun showed good performances, for our purpose, to drive an X-ray FEL, the RF gun with a highest cathode electric field peak and a highest beam energy at the exit was preferable. Therefore, the gun presented in this work is a VHF RF gun like the APEX-I [6], working with a Cs 2 Te phothocathode [7][8][9], driven by an Yb:Yag IV harmonic laser pulse (257.5 nm), at 1 MHz rep rate.…”

Section: Machine Layoutmentioning

confidence: 99%

GeV-Class Two-Fold CW Linac Driven by an Arc-Compressor

et al. 2019

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We present a study of an innovative scheme to generate high repetition rate (MHz-class) GeV electron beams by adopting a two-pass two-way acceleration in a super-conducting Linac operated in Continuous Wave (CW) mode. The beam is accelerated twice in the Linac by being re-injected, after the first pass, in opposite direction of propagation. The task of recirculating the electron beam is performed by an arc compressor composed by 14 Double Bend Achromat (DBA). In this paper, we study the main issues of the two-fold acceleration scheme, the electron beam quality parameters preservation (emittance, energy spread), together with the bunch compression performance of the arc compressor, aiming to operate an X-ray Free Electron Laser. The requested power to supply the cryogenic plant and the RF sources is also significantly reduced w.r.t a conventional one-pass SC Linac for the same final energy.

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“…1. Table I shows the gun main parameters while a detailed description of the gun fabrication can be found in [13]. After the completion of the beam tests that demonstrated beams with the characteristics required to operate a high repetition rate FEL [6], the APEX VHF gun is now used at LBNL as the source for high repetition rate UED experiments in the framework of the HiRES project [14].…”

Section: Characteristics Of the Vhf-gun Schemementioning

confidence: 99%

“…The tuner system was also modified to extend (double) the range of tunability of the cavity frequency. Other minor modifications were implemented and are described in more detail in [13].…”

Section: Characteristics Of the Vhf-gun Schemementioning

confidence: 99%

Upgrade possibilities for continuous wave rf electron guns based on room-temperature very high frequency technology

Sannibale

Filippetto

Johnson

et al. 2017

Phys. Rev. Accel. Beams

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The past decade was characterized by an increasing scientific demand for extending towards higher repetition rates (MHz class and beyond) the performance of already operating lower repetition rate accelerator-based instruments such as x-ray free electron lasers (FELs) and ultrafast electron diffraction (UED) and microscopy (UEM) instruments. Such a need stimulated a worldwide spread of a vibrant R&D activity targeting the development of high-brightness electron sources capable of operating at these challenging rates. Among the different technologies pursued, rf guns based on room-temperature structures resonating in the very high frequency (VHF) range (30-300 MHz) and operating in continuous wave successfully demonstrated in the past few years the targeted brightness and reliability. Nevertheless, recently proposed upgrades for x-ray FELs and the always brightness-frontier applications such as UED and UEM are now requiring a further step forward in terms of beam brightness in electron sources. In this paper, we present a few possible upgrade paths that would allow one to extend, in a relatively simple and cost-effective way, the performance of the present VHF technology to the required new goals.

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Mechanical design and fabrication of the VHF-gun, the Berkeley normal-conducting continuous-wave high-brightness electron source

Cited by 17 publications

References 13 publications

High-brightness beam tests of the very high frequency gun at the Advanced Photo-injector EXperiment test facility at the Lawrence Berkeley National Laboratory

High-brightness beam tests of the very high frequency gun at the Advanced Photo-injector EXperiment test facility at the Lawrence Berkeley National Laboratory

GeV-Class Two-Fold CW Linac Driven by an Arc-Compressor

Upgrade possibilities for continuous wave rf electron guns based on room-temperature very high frequency technology

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