Speaker
Description
Particle therapy with protons and heavy ions relies on a precise understanding of nuclear interactions in tissue. In this context, nuclear fragmentation processes, in particular target and beam fragmentations, play a crucial role, producing secondary fragments with high linear energy transfer and impacting dose deposition and radiobiological effectiveness. However, at present fragmentation cross sections in the therapeutic energy range remain insufficiently constrained.
The FOOT (FragmentatiOn Of Target) experiment is designed to perform high-precision measurements of nuclear fragmentation cross sections in the 50-700 MeV/n energy range, with a target uncertainty of ~5%. Using inverse kinematics with 16O and 12C beams on C and C2H4 targets, FOOT investigates reaction mechanisms and fragment production over a broad charge range. This approach overcomes the intrinsic limitation of direct kinematics, where low-energy target fragments typically stop within the target material and remain experimentally inaccessible. First results obtained with 200 and 400 MeV/n 16O beams will be presented.
The possibility of performing the first direct measurement of target fragmentation induced by proton beams is being explored by the DAMON (Direct meAsureMent of target fragmentatiON) project, which has been funded by the European Union - Next Generation EU, Mission 4 Component 1, CUP H53D23001090006. DAMON employs Nano-Imaging Trackers (NITs), based on ultra-fine nuclear emulsion films with nanometric AgBr crystals, which provide sub-micrometre spatial resolution. This enables the reconstruction of short tracks from low-energy recoils and target fragments directly at the production point, without relying on kinematic boosting. The direct kinematics configuration is essential to access the genuine topology and phase space of proton-induced target fragmentation, providing observables that are otherwise inaccessible and offering a fully complementary perspective to inverse kinematics measurements. Exposures have been performed with proton beams in the 70-211 MeV range at several facilities: Trento Proton Therapy Center (Trento, Italy), CNAO (Pavia, Italy), HIMAC (Chiba, Japan) and the Nagoya Proton Therapy Center (Nagoya, Japan). The first results demonstrate the potential of NIT technology for precision studies of proton-induced nuclear fragmentation.
Results from both experiments provide new constraints on reaction channels and fragment yields in light-ion interactions with tissue-equivalent materials, contributing to a more accurate description of nuclear processes at therapeutic energies and offering relevant input for both nuclear reaction modelling and applied nuclear physics.