Analytical scaling laws and main guide-lines for the design of RF gun cavities

In this paper the results of an extensive analytical study of the beam dynamics in RF guns are reported: removing some approximations of Kim's model, such as the absence of higher spatial harmonics, the relevant beam properties at the gun exit (emittances, compressibility, etc) are derived as functions of the RF cavity characteristics. By means of the reported formulas one can find, once chosen the desired beam performances, the optimum value for the first half cell length, the high harmonic content and the laser pulse shape. A possible method for the neutralization of the space charge induced emittance is also proposed. (author). 8 refs