FIRST experiment: measurements of differential cross sections in 12C fragmentation for hadron-therapy and space applications

The aim of the present work is to describe some preliminary results obtained within the experiment FIRST (Fragmentation of Ions Relevant for Space and Therapy). This experiment main goal is to measure the differential cross-sections in energy and angle of nuclear fragmentation processes, in a wide energy range (between 100 and 1000 MeV/n). The knowledge of these cross sections will be useful for cancer therapy and space radiation protection. This experiment was carried out because there is a strong need of high-quality experimental data concerning 12 C, 16 O and 56 Fe fragmentation on different targets. The first data taking has been performed at SIS (Heavy Ion Synchrotron) accelerator of GSI Laboratory in Darmstadt (Germany) during August 2011. Different sets of data have been collected using a 400 MeV/n carbon beam impinging on carbon and gold targets. Experimental data of single and double-differential cross sections for C-ions at energies less or equal to 400 MeV/n are needed to improve treatment plannings in particle-therapy. In particular accurate measurements of cross sections of light ions are urgently needed for improving transport codes to be used in cancer therapy. Algorithms that deal with the transport of charged particle in matter are essential for accurate treatment plannings, in order to evaluate possible long term side effects of dose released in healthy tissue. Unfortunately, the production of light fragments and their angular distribu- tions are affected by large uncertainties and various Monte Carlo codes may differ up to one order of magnitude in their predictions. Moreover, codes used for space radiation transport in shielding materials need more information on the fragmentation effects. Recently, NASA completed a large database of these measurements and observed that there are ion species and kinetic energy ranges not yet evaluated. The FIRST experiment aims to contribute to the knowledge of these nu- clear processes and to investigate the secondary effects on human tissues of hadron’s irradiation. In fact, most of the measurements carried out in the past are limited to fragment yields and to total fragmentation cross-sections, while the required measurements of single or double-differential cross-sections are deficient.