1. J.D. Lawson, The Physics of Charged-Particle Beams, Clarendon Press, Oxford, 1988, p. 192. I include the factor ofπ, making this the phase-space area. Then the effective emittance becomes equivalent to the wavelength of a light beam.
2. C.A. Brau, Free-Electron Lasers, Academic Press, Boston, 1989, p. 173.
3. J.D. Lawson, The Physics of Charged-Particle Beams, Clarendon Press, Oxford, 1988, p. 160.
4. C.A. Brau, Free-Electron Lasers, Academic Press, Boston, 1989, p. 164.
5. Electron emission in intense electric fields