A low-cost portable system for elemental mapping by XRF aiming in situ analyses - Campos, Pedro Herzilio Ottoni Viviani de; Appoloni, Carlos Roberto; Rizzutto, Márcia de Almeida; Leite, A. R.; Assis, R. F.; Santos, H. C.; Silva, Tiago Fiorini da; Rodrigues, C. L.; Tabacniks, Manfredo Harri; Added, Nemitala (Applied Radiation and Isotopes, 2019)