Radial bunch compression: Path-length compensation in an rf photoinjector with a curved cathode oleh M. J. de Loos, S. B. van der Geer, Y. M. Saveliev, V. M. Pavlov, A. J. W. Reitsma, S. M. Wiggins, J. Rodier, T. Garvey, D. A. Jaroszynski