Different fields can profit by nuclear fragmentation cross section measurements: among them hadrontherapy and space radioprotection are of particular interest. Hadrontherapy employs high-energy beams ...of charged particles (protons and heavier ions) to treat deep-seated tumours. In these treatments nuclear interactions have to be considered: beam particles can fragment in the human body releasing a non-zero dose beyond the tumour while fragments of human body nuclei can modify the dose released in healthy tissues.
On the radioprotection side, the interest in long-term manned space missions beyond Low Earth Orbit is growing in these years but it has to cope with significant health concerns from radiation in space, necessitating an accurate cross section data description. The FOOT (FragmentatiOn Of Target) experiment was proposed to cover these gaps in data. It was designed to detect, track and identify nuclear fragments and aims to measure double differential cross sections both in angle and kinetic energy which is the most complete information to address existing questions. The FOOT experimental setups, the experimental program and a first cross section analysis of 400 MeV/u
16
O beam on Carbon target data acquired in July 2021 at GSI (Darmstadt, Germany) will be presented.
The FOOT experiment Ridolfi, Riccardo
Journal of physics. Conference series,
10/2020, Volume:
1667, Issue:
1
Journal Article
Peer reviewed
Open access
The main goal of the FOOT (FragmentatiOn Of Target) experiment is the measurement of the differential cross sections with respect to the energy and angle of the produced fragments in nuclear ...interactions between an ion beam, such as proton, Helium, Carbon, and different targets (proton, Carbon, Oxygen). Two important fields can benefit from these kind of measurements: firstly, in the 150 - 400MeV/u beam energy range, the data will be used to evaluate the nuclear fragmentation occurring in a standard hadrontherapy treatment and thus potential side effects. Secondly, in the 700 - 1000MeV/u beam energy range, the FOOT experiment aims at studying novel shields for spacecrafts involved in long term missions within the Solar System. The experiment has been funded by INFN since September 2017 and it is currently in its construction phase while the first data taking is scheduled by the end of 2020. A description of the experiment and a overview of expected performances and test beam results will be presented.
Space agencies have recognized the risks of astronauts’ exposure to space radiation and are developing complex model-based risk mitigation strategies. In the foundation of these models, there are ...still significant gaps of knowledge concerning nuclear fragmentation reactions which need to be addressed by ground-based experiments. There is a lack of data on neutron and light ion production by heavy ions, which are an important component of galactic cosmic radiation (GCR). A research collaboration has been set up to characterize the secondary radiation field produced by GCR-like radiation provided by a particle accelerator in thick shielding. The aim is to develop a novel method for producing high-quality experimental data on neutron and light ion production in shielding materials relevant for space radiation protection. Four complementary detector systems are used to determine the energy and angular distributions of high-energy secondary neutrons and light ions. In addition to the physical measurement approach, the biological effectiveness of the secondary radiation field is determined by measuring chromosome aberrations in human peripheral lymphocytes placed behind the shielding. The experiments are performed at the heavy ion
The study that we present is part of the preparation work for the setup of the FOOT (FragmentatiOn Of Target) experiment whose main goal is the measurement of the double differential cross sections ...of fragments produced in nuclear interactions of particles with energies relevant for particle therapy. The present work is focused on the characterization of the gas-filled drift chamber detector composed of 36 sensitive cells, distributed over two perpendicular views. Each view consists of six consecutive and staggered layers with three cells per layer. We investigated the detector efficiency and we performed an external calibration of the space–time relations at the level of single cells. This information was then used to evaluate the drift chamber resolution. An external tracking system realized with microstrip silicon detectors was adopted to have a track measurement independent on the drift chamber. The characterization was performed with a proton beam at the energies of 228 and 80 MeV. The overall hit detection efficiency of the drift chamber has been found to be 0.929±0.008, independent on the proton beam energy. The spatial resolution in the central part of the cell is about 150±10μ m and 300±10μ m and the corresponding detector angular resolution has been measured to be 1.62±0.16 mrad and 2.1±0.4 mrad for the higher and lower beam energies, respectively. In addition, the best value on the intrinsic drift chamber resolution has been evaluated to be in the range 60−100μ m. In the framework of the FOOT experiment, the drift chamber will be adopted in the pre-target region, and will be exploited to measure the projectile direction and position, as well as for the identification of pre-target fragmentation events.
Oncological hadrontherapy is a novel technique for cancer treatment that improves over conventional radiotherapy by having higher effectiveness and spatial selectivity. The FOOT (FragmentatiOn Of ...Target) experiment studies the nuclear fragmentation caused by the interactions of charged particle beams with patient tissues in Charged Particle Therapy. Among the several FOOT detectors, the silicon Microstrip Detector is part of the charged-ions-tracking magnetic spectrometer. The detector consists of three x-y planes of two silicon microstrip detectors arranged orthogonally between each other to enable tracking capabilities. Ten analog buffer chips and five ADCs read out each detector. A Field-Programmable Gate Array collects the output of the ADCs of an x-y plane, possibly processes the data, and forms a packet to be sent to the experiment central data acquisition. This data acquisition system shall withstand the trigger rate and detector's throughput at any time. In this work, we discuss the architecture of the data acquisition system-in particular of the silicon microstrip detector one-and the first results obtained from the x-y plane's prototype.
•We focus on how river flow fluctuations (RFF) affect riparian vegetation dynamics.•The most relevant mechanisms are reviewed from a processes-based perspective.•The advances gained from a modeling ...point of view are considered and discussed.•The main models developed for RFF-riparian vegetation interactions are presented.•Different modeling approaches and results are compared.
Several decades of field observations, laboratory experiments and mathematical modelings have demonstrated that the riparian environment is a disturbance-driven ecosystem, and that the main source of disturbance is river flow fluctuations. The focus of the present work has been on the key role that flow fluctuations play in determining the abundance, zonation and species composition of patches of riparian vegetation. To this aim, the scientific literature on the subject, over the last 20 years, has been reviewed. First, the most relevant ecological, morphological and chemical mechanisms induced by river flow fluctuations are described from a process-based perspective. The role of flow variability is discussed for the processes that affect the recruitment of vegetation, the vegetation during its adult life, and the morphological and nutrient dynamics occurring in the riparian habitat. Particular emphasis has been given to studies that were aimed at quantifying the effect of these processes on vegetation, and at linking them to the statistical characteristics of the river hydrology. Second, the advances made, from a modeling point of view, have been considered and discussed. The main models that have been developed to describe the dynamics of riparian vegetation have been presented. Different modeling approaches have been compared, and the corresponding advantages and drawbacks have been pointed out. Finally, attention has been paid to identifying the processes considered by the models, and these processes have been compared with those that have actually been observed or measured in field/laboratory studies.
In the field of renewable-energies, a number of engineering problems are modeled as dynamical systems, and a key issue is the assessment of their stability to external disturbances. Stability ...analyses typically focus on the asymptotic stability, i.e., the fate of perturbations after long times from their onset. The system behavior at finite-times has attracted much less attention, although it plays a crucial role in determining the system dynamics. In this work, we focus on the response at finite-times to perturbations in run-of-river hydropower plants. These are widespread systems in the hydropower industry. We show that their response at finite-times (i) can be analytically studied by the non-modal analysis, and (ii) can be very different from the asymptotic-times response. In particular, perturbations can exhibit very relevant transient amplifications (with important technical consequences), although the system is asymptotically stable. The proposed analytical approach is general and can be applied to investigate the finite-time response of any dynamical system.
•We focus on the response to perturbations of run-of-river (ROR) hydro-powerplants.•Former studies have considered only the asymptotic fate of perturbations.•In asymptotically stable ROR plants, perturbation may be amplified at finite times.•Transient amplification of perturbations have very relevant technical consequences.•We give mathematical tools to study the response to perturbations at finite-times.
Our focus is on the short-term dynamics of reactive ecological systems which are stable in the long term. In these systems, perturbations can exhibit significant transient amplifications before ...asymptotically decaying. This peculiar behavior has attracted increasing attention. However, reactive systems have so far been investigated assuming that external environmental characteristics remain constant, although environmental conditions (e.g., temperature, moisture, water availability, etc.) can undergo substantial changes due to seasonal cycles. In order to fill this gap, we propose applying the adjoint non-modal analysis to study the impact of seasonal variations of environmental conditions on reactive systems. This tool allows the transient dynamics of a perturbation affecting non-autonomous ecological systems to be described. To show the potential of this approach, a seasonally forced prey-predator model with a Holling II type functional response is studied as an exemplifying case. We demonstrate that seasonalities can greatly affect the transient dynamics of the system.
•We focus on the short-term dynamics of stable reactive ecological systems.•The commonly adopted hypothesis of constant environmental conditions is removed.•Conceptual and mathematical tools to study reactive non-autonomous systems are given.•The adjoint nonmodal analysis is performed on the seasonal Rosenzweig-McArthur model.•Seasonalities can deeply impact the short-term dynamics of perturbations.
In this research work a case study dealing with the identification of the main hydrodynamic properties of an Autonomous Underwater Vehicle (AUV) is presented. The vehicle is the Typhoon-class AUV ...developed by the Department of Industrial Engineering of the University of Florence, Italy. The identification of the main hull hydrodynamic parameters is very important for the tuning of an accurate dynamic model of the vehicle, which could be used for several purposes including the development of model based localization and navigation filters. The authors describe the simplified identification procedure adopted for the Typhoon AUV starting from a reduced experimental dataset obtained during some missions at sea performed in 2014 in Biograd na Moru, Croatia.
•Fast identification procedure of an AUV from a few experimental underwater data.•Complete dynamic modelling of the hydrodynamic behaviour of an AUV.•Calibration and validation of the simulation models through experimental data.
We study the dynamics of a naturally ventilated room in which a point source provides a steady source of buoyancy and which is affected by an opposing unsteady wind. The wind is modelled as a ...stochastic forcing, which aims at simulating realistic velocity fluctuations as observed in the lower atmosphere. Our main finding is the occurrence of a “noise-induced transition”, namely a structural change of the mean behaviour of the system: the warm–cold air interface does not fluctuate around the elevation exhibited when wind is constant, but oscillations occur around a new (significantly lower) interface elevation. We provide the physical explanation for such a counter-intuitive behaviour and show its dependence on (i) wind characteristics (intensity and timescale of fluctuations) and (ii) relative strength of wind over thermal loads. A realistic example case shows that the behaviour highlighted here has potentially major implications in the design and management of naturally ventilated buildings.
•Topic: natural ventilation of rooms (point buoyancy source) forced by stochastic wind.•We compare the system response to stochastic and constant winds (same mean velocity).•Mean configurations attained under constant and fluctuating wind are very different.•Wind fluctuations induce a worsening of the ventilation performance of the room.
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