Multi Colour X-Gamma Ray Inverse Compton Back-Scattering Source

We present a simple and new scheme for producing multi-colour Thomson/Compton radiation with the possibility of controlling separately their polarization, based on the interaction of one single electron beam with two and more laser pulses that can come from the same laser setup or from two different lasers system and that collide with the electrons at different angle inside one optical cavity. One of the most interesting cases for medical applications is to provide two X-ray pulses across the iodine K-edge at 33.2 keV. The iodine is used as contrast medium in various imaging techniques and the availability of two spectral lines across the K-edge allows one to produce subtraction images with a great increase in accuracy .