Modeling and design of an<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>X</mml:mi></mml:math>-band rf photoinjector

Marsh, Roark; Albert, F.; Anderson, S. G.; Beer, G.; Chu, T.S.; Cross, Robert R.; Deis, G.A.; Ebbers, C.A.; Gibson, D. J.; Houck, T.; Hartemann, F. V.; Barty, C. P. J.; Candel, A.; Jongewaard, E.; Li, Z.; Limborg-Deprey, C.; Vlieks, A.E.; Wang, F.; Wang, J. W.; Zhou, Feng; Adolphsen, C.; Raubenheimer, T.O.

doi:10.1103/physrevstab.15.102001

Cited by 17 publications

(15 citation statements)

References 19 publications

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“…The Mark 1 X-band rf gun shows marked improvement in emittance over the first generation (Mark 0) results of 0.7 mm mrad at 100 pC [9] and good agreement with modeling [22]. A charge per bunch from a few pC to 500 pC has been measured, consistent with a quantum efficiency of 5.3 × 10 −5 (AE0.4).…”

Section: Discussionsupporting

confidence: 68%

“…rf and beam dynamics modeling was done using a combination of codes as reported in [22]. The Mark 1 parameters are summarized in Table I and a photograph is shown in Fig.…”

Section: Rf Gunmentioning

confidence: 99%

“…LLNL has a long history of work on narrowband gamma-ray light sources [13][14][15][16][17][18][19][20], and designed the all X-band VELOCIRAPTOR linac [21]. The X-band photoinjector [22] discussed here was originally designed to serve as the electron source for the VELOCIRAPTOR, and LLNL commissioned the MEGa-ray (Mono-Energetic Gammaray) Test Station (MTS) to leverage hardware in hand into a platform for developing the critical technologies for optimized Laser-Compton scattering with an X-band accelerator [23].…”

Section: Introductionmentioning

confidence: 99%

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Performance of a second generation X -band rf photoinjector

Marsh

Anderson

et al. 2018

Phys. Rev. Accel. Beams

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rf photoinjectors produce incredibly bright electron beams enabling advanced photon science applications such as the current generation of free electron lasers and high energy x-rays and gammarays via laser-Compton scattering. A second generation 5.59 cell X-band rf gun has been developed, installed, conditioned, commissioned, tuned, and used to produce laser-Compton x-rays and multiple electron bunches. A charge per bunch from a few pC to 500 pC has been measured, consistent with a quantum efficiency of 5 × 10 −5 using a 263 nm 10 Hz photocathode drive laser. The rf gun has operated close to design performance at high gradient, and more reliably at lower gradient achieving a root mean square normalized emittance of 0.3 mm mrad at both 80 pC at 185 MV=m, and 40 pC at 165 MV=m. Thermal emittance is estimated at 0.55 mm mrad=mm. Energy spread of 0.03% has been achieved. These results agree very well with modeling predictions for the operating conditions under which the measurements were made. Unusually disruptive breakdowns were observed with an applied magnetic field of 0.5T used for emittance compensation.

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Section: Discussionsupporting

confidence: 68%

“…rf and beam dynamics modeling was done using a combination of codes as reported in [22]. The Mark 1 parameters are summarized in Table I and a photograph is shown in Fig.…”

Section: Rf Gunmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Performance of a second generation X -band rf photoinjector

Marsh

Anderson

et al. 2018

Phys. Rev. Accel. Beams

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“…The X-band test area (XTA) at SLAC was initially designed to test X-band RF photoelectron guns for compact FELs (Sun et al, 2012), and compact inverse Compton scattering sources (Marsh et al, 2012). In this paper, we discuss its potential as a source for UED experiments.…”

Section: Introductionmentioning

confidence: 99%

Femtosecond Electron Imaging and Spectroscopy

Berz

Duxbury

Makino

et al. 2015

Advances in Imaging and Electron Physics

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“…As such, one may not easily simultaneously improve on the launch field and transverse dynamics obtained at, e.g., the LCLS using present techniques. Also, in X-band the emittance compensation focusing solenoids are very challenging [30]. Indeed, the brightness obtained in X-band photoinjectors has not yet yielded significant improvement NEXT GENERATION HIGH BRIGHTNESS ELECTRON … PHYS.…”

Section: Introductionmentioning

confidence: 99%

Next generation high brightness electron beams from ultrahigh field cryogenic rf photocathode sources

Rosenzweig

Cahill

Dolgashev

et al. 2019

Phys. Rev. Accel. Beams

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Recent studies of the performance of radio-frequency (rf) copper cavities operated at cryogenic temperatures have shown a dramatic increase in the maximum achievable surface electric field. We propose to exploit this development to enable a new generation of photoinjectors operated at cryogenic temperatures that may attain, through enhancement of the launch field at the photocathode, a significant increase in fivedimensional electron beam brightness. We present detailed studies of the beam dynamics associated with such a system, by examining an S-band photoinjector operated at 250 MV=m peak electric field that reaches normalized emittances in the 40 nm-rad range at charges (100-200 pC) suitable for use in a hard x-ray free-electron laser (XFEL) scenario based on the LCLS. In this case, we show by start-to-end simulations that the properties of this source may give rise to high efficiency operation of an XFEL, and permit extension of the photon energy reach by an order of magnitude, to over 80 keV. The brightness needed for such XFELs is achieved through low source emittances in tandem with high current after compression. In the XFEL examples analyzed, the emittances during final compression are preserved using microbunching techniques. Extreme low emittance scenarios obtained at pC charge, appropriate for significantly extending temporal resolution limits of ultrafast electron diffraction and microscopy experiments, are also reviewed. While the increase in brightness in a cryogenic photoinjector is mainly due to the augmentation of the emission current density via field enhancement, further possible increases in performance arising from lowering the intrinsic cathode emittance in cryogenic operation are also analyzed. Issues in experimental implementation, including cavity optimization for lowering cryogenic thermal dissipation, external coupling, and cryocooler system, are discussed. We identify future directions in ultrahigh field cryogenic photoinjectors, including scaling to higher frequency, use of novel rf structures, and enabling of an extremely compact hard x-ray FEL.

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Modeling and design of anX-band rf photoinjector

Cited by 17 publications

References 19 publications

Performance of a second generation X -band rf photoinjector

Performance of a second generation X -band rf photoinjector

Femtosecond Electron Imaging and Spectroscopy

Next generation high brightness electron beams from ultrahigh field cryogenic rf photocathode sources

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