Dr
Matteo Franchini
(University of Bologna)
The main goal of the FOOT (FragmentatiOn Of Target) experiment is the measurement of the differential cross sections as a function of energy and direction of the produced fragments in the nuclear interaction between a ion beam (proton, helium, carbon, ...) and different targets (proton, carbon, oxygen, ...). Depending on the beam energy, the purpose of the measurements is twofold: in the [150-400] MeV/u range, the data will be used to evaluate the side effects of the nuclear fragmentation in the hadrontherapy treatment, while in the [700-1000] MeV/u range it will be used to optimize the shielding of spaceships for long term space missions.
Particle therapy uses proton or 12-C beams in the [150-400] MeV/u range for the treatment of deep-seated solid tumours. Due to the features of energy deposition of charged particles a small amount of dose is released to the healthy tissue in the beam entrance region, while the maximum of the dose is released to the tumour at the end of the beam range, in the Bragg peak region. Dose deposition is dominated by electromagnetic interactions but nuclear interactions between beam and patient tissues inducing fragmentation processes must be carefully taken into account. In proton treatment the target fragmentation produces low energy, short range fragments along all the beam range. In 12-C treatments the main concern are long range fragments due to projectile fragmentation that release dose in the healthy tissue after the tumor.
The XXI century will be characterized by a deeper exploration of the Solar System that will involve long term missions as the expedition to Mars. Health risks are associated to exposure to galactic cosmic radiation (GCR), that is very energetic (on average around 700-1000 MeV/u) and produces showers of light fragments and neutrons by nuclear fragmentation when hitting the spaceship shields. This suggests to study the differential cross section of the nuclear interaction between the GCR and the different materials composing the spaceship shields. Considering that the GCR are composed of 90% of protons, 9% of helium and the rest of heavy nuclei, the overlap with the measurements for hadrontherapy purposes is large, the main difference being the energy range.
The FOOT detector includes a magnetic spectrometer based on silicon pixel and strip detectors, a TOF and ΔE scintillating detector and finally a scintillating crystal calorimeter for the fragment identification. In addition, a different setup with an emulsion spectrometer inserted before the target is foreseen to characterize the production of low Z fragments. The experiment is being planned as a ‘table-top’ experiment in order to cope with the small dimensions of the experimental halls of the CNAO, LNS, GSI and HIT treatment centers, where the data taking is foreseen in the near future (2020). The detector, the physical program, the results obtained at several beam tests of the experiment will be presented as well as the results of a Monte Carlo study, which aims to evaluate the detector performance and the expected resolution on fragment identification and on the nuclear cross sections.
Summary
The main goal of the FOOT (FragmentatiOn Of Target) experiment is the measurement of the differential cross sections of the produced fragments in the nuclear interaction between a ion beam (proton, helium, carbon, ...) and different targets (proton, carbon, oxygen, ...). Depending on the beam energy, the purpose of the measurements is twofold: in the [150-400] MeV/u range, the data will be used to evaluate the side effects of the nuclear fragmentation in the hadrontherapy treatment, while in the [700-1000] MeV/u range it will be used to optimize the shielding of spaceships for long term space missions. Both the hadrontherapy and the radioprotection in space are two crucial topics in the field of physics in the next future .
In the last decade a continuous increase in the number of cancer patients treated with Charged Particle Therapy has been registered, due to its effectiveness in the treatment of deep seated solid tumours. The main advantage of this approach derives from the depth-dose profile of charged particles, characterized by a low amount of dose released in the entrance channel, followed by a narrow region, the Bragg Peak where the maximum of the dose is released.
While the XX century will be remembered for the first human space travel, the XXI century will be characterized by the colonization of the Solar System. Current exploration programs include missions to near-Earth asteroids, the moon (Moon Village) and Mars for which it is essential to evaluate the absorbed dose by the astronauts in order to estimate the increase of the tumour risk.
