Document Type

Conference Paper

Publication Date




Publication Title

Proceedings of the 12th International Particle Accelerator Conference



Conference Name

IPAC2021: 12th International Particle Accelerator Conference, May 24-28, 2021, Campinas, Brazil


Production of high bunch charge beams for the ElectronIon Collider (EIC) is a challenging task. High bunch charge (a few nC) electron beam studies at Jefferson Lab using an inverted insulator DC high voltage photo-gun showed evidence of space charge limitations starting at 0.3 nC, limiting the maximum delivered bunch charge to 0.7 nC for beam at -225 kV, 75 ps (FWHM) pulse width, and 1.64 mm (rms) laser spot size. The low extracted charge is due to the modest longitudinal electric field (Ez) at the photocathode leading to beam loss at the anode and downstream beam pipe. To reach the few nC high bunch charge goal, and to correct the beam deflection exerted by the non-symmetric nature of the inverted insulator photo-gun the existing photo-gun was modified. This contribution discusses the electrostatic design of the modified photo-gun obtained using CST Studio Suite’s electromagnetic field solver. Beam dynamics simulations performed using General Particle Tracer (GPT) with the resulting electrostatic field map obtained from the modified electrodes confirmed the validity of the new design.


Published by JACoW Publishing under the terms of the Creative Commons Attribution 3.0 Unported license (CC BY 3.0). Any further distribution of this work must maintain attribution to the authors, the published article's title, publisher, and DOI.

Original Publication Citation

Wijethunga, S. A. K., Benesch, J., Delayen, J. R., Hernandez-Garcia, C., Krafft, G. A., Palacios-Serrano, G., Mamun, M. A., Poelker, M., & Suleiman, R. (2021) Redesign of the Jefferson Lab -300 kV DC photo-gun for high bunch charge operations. In L. Liu, J. Byrd, R. Neuenschwander, V.R.W. Schaa (Eds.), Proceedings of the 12th International Particle Accelerator Conference (pp. 2802-2805). JACoW.


0000-0002-0328-5828 (Krafft), 0000-0002-5331-6127 (Palacios Serrano)