A GREENS-FUNCTION METHOD FOR HEAVY-ION BEAM TRANSPORT

The use of Green's function has played a fundamental role in transport calculations for high-charge high-energy (HZE) ions. Two recent devel opments have greatly advanced the practical aspects of implementation of these methods, The first was the formulation of a closed-form solut ion as a multiple fragmentation perturbation series, The second was th e effective summation of the closed-form solution through nonperturbat ive techniques, The nonperturbative methods have been recently extende d to an inhomogeneous, two-layer transport media to simulate the lead scattering foil present in the Lawrence Berkeley Laboratories (LBL) bi omedical beam line used for cancer therapy. Such inhomogeneous codes a re necessary for astronaut shielding in space. The transport codes uti lize the Langley Research Center atomic and nuclear database. Transpor t code and database evaluation are performed by comparison with experi ments performed at the LBL Bevalac facility using 670 A MeV Ne-20 and 600 A MeV Fe-56 ion beams. The comparison with a time-of-flight and De lta E detector measurement for the Ne-20 beam and the plastic nuclear track detectors for Fe-56 show agreement up to 35%-40% in water and al uminium targets, respectively.