Superconducting non-scaling FFAG gantry for carbon/proton cancer therapy

We report on improvements in the non-scaling fixed field alternating gradient (FFAG) gantry design. As we previously reported [1], a major challenge of the carbon/proton cancer therapy facilities is in the isocentric gantry design. The weight of the isocentric gantry transport elements in the latest Heidelberg carbon/proton facility is 135 tons [4]. In this report we detail improvements to the previous non-scaling gantry design. We estimate that this non-scaling FFAG gantry would be almost a hundred times lighter than traditional heavy ion gantries. Very strong focusing with small dispersion permits passage of different energies of carbon beams through the gantry's fixed magnetic field.