Experimental Evidence for Particle Acceleration by Stimulated Emission of Radiation

The interaction of electromagnetic radiation with free electrons in the presence of an active medium has several appealing outcomes. Among them the PASER scheme, standing for Particle Acceleration by Stimulated Emission of Radiation. In the framework of this scheme, energy stored in an active medium (microscopic cavities) is transferred directly to an e-beam traversing the medium, and therefore, accelerating the former. Recently, a proof-of-principle experiment of this concept was performed at the Brookhaven National Laboratory reaching a gain of 200keV in the kinetic energy of a 5ps, 0.1nc and 45MeV quasi-mono-energetic macro-bunch which is modulated by its interaction with a CO2 laser pulse in an adequate wiggler. In the framework of this proof-of-principle experiment both the fundamental frequency of the train of micro-bunches and the medium's resonance frequency (CO2 mixture) are matched. A good agreement is found between the energy gain and a 2D analytic model that has been developed