A beam focusing system for a linac driven by a traveling laser focus

Described is a focusing system for charged particles in a laser driven linac, with an accelerating structure that is open on one side. The structure is illuminated from the open side by a focused laser spot, which is traveling along the structure in correlation with the position of the particles. This method allows for the reduction of the power required for generation of the necessary accelerating gradient, and reduction of the time of illumination of each point in the structure. This makes a laser driven linac a realistic system. The focusing system is a combination of FODO structure arranged with quadrupole lenses of appropriate dimensions and RF focusing. The final focusing system is arranged with the help of a bifrequency RF focusing system supplied by laser radiation of fundamental and doubled frequency.