Optimisation of an ion optical range adaptation method for beam tracking of moving tumours with scanned ion beams

An ion optical solution for beam tracking of moving tumours with scanned ion beams is currently being investigated at GSI [1, 2]. Thereby the longitudinal compensation is achieved by using the deflection magnets of the therapy beam line to direct the particle beam to different positions on a static energy degrader with variable thickness, which is installed upstream of the scanning magnets. Thus the range of the Bragg-peak can in principle be adjusted within as no mechanical device is required. The initial feasibility of this method was studied both in simulations as well as in experiments [1, 3]. In order to optimise the method, systematic studies have to be carried out. Simulations results concerning the wedge shape and its material will be presented here.