Comment on "How to Realize Uniform Three-Dimensional Ellipsoidal   Electron Bunches"
  Via systematic numerical simulation we found that the recently propose 'Pancake' scheme [O. J. Luiten et al., Phys. Rev. Lett. 93, 094802 (2004)] does not generate a beam desired for low emittance, even when compared with the more traditionally accepted cylindrical beam geometry. 
Yuelin Li