Double Differential Fragmentation Cross Sections Research Articles

Elemental fragmentation cross sections for a 16O beam of 400 MeV/u kinetic energy interacting with a graphite target using the FOOT ΔE-TOF detectors

The study of nuclear fragmentation plays a central role in many important applications: from the study of Particle Therapy (PT) up to radiation protection for space (RPS) missions and the design of shielding for nuclear reactors. The FragmentatiOn Of Target (FOOT) collaboration aims to study the nuclear reactions that describe the interactions with matter of different light ions (like H1, He4, C12, O16) of interest for such applications, performing double differential fragmentation cross section measurements in the energy range of interest for PT and RPS. In this manuscript, we present the analysis of the data collected in the interactions of an oxygen ion beam of 400 MeV/u with a graphite target using a partial FOOT setup, at the GSI Helmholtz Center for Heavy Ion Research facility in Darmstadt. During the data taking the magnets, the silicon trackers and the calorimeter foreseen in the final FOOT setup were not yet available, and hence precise measurements of the fragments kinetic energy, momentum and mass were not possible. However, using the FOOT scintillator detectors for the time of flight (TOF) and energy loss (ΔE) measurements together with a drift chamber, used as beam monitor, it was possible to measure the elemental fragmentation cross sections. The reduced detector set-up and the limited available statistics allowed anyway to obtain relevant results, providing statistically significant measurements of cross sections eagerly needed for PT and RPS applications. Whenever possible the obtained results have been compared with existing measurements helping in discriminating between conflicting results in the literature and demonstrating at the same time the proper functioning of the FOOT ΔE-TOF system. Finally, the obtained fragmentation cross sections are compared to the Monte Carlo predictions obtained with the FLUKA software.

Performance Evaluation of the TOF-Wall Detector of the FOOT Experiment

The correct quantification of the dose released in charged particle therapy treatments requires the knowledge of the double differential fragmentation cross section of particles composing both the beam and the target. The FragmentatiOn Of Target (FOOT) experiment aims at measuring these cross sections for ions of interest for charged particle therapy applications. This article describes the performance of the time-of-flight (TOF)-wall detector of the experiment. The detector is composed of two layers of 44 cm ×2 cm ×3 mm plastic scintillator bars (20 for each layer), arranged orthogonally and read-out by silicon photomultipliers. The detector is designed to identify the charge of fragments ranging from protons to oxygen ions, with a maximum energy of 700 MeV/u, by measuring the energy released in the scintillators and the TOF with respect to a start counter. In this study, the detector was scanned with carbon ions of energy between 115 and 400 MeV/u and with a 60-MeV proton beam. The measurements show an energy resolution (σ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</sub> /μ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</sub> ) between 6% and 4% and a contribution of the detector to the TOF system time resolution between 25 and 20 ps (standard deviation) for carbon ions and between 100 and 80 ps for protons.

Dissociative multiple ionization of the H2O molecule induced by ion impact: experimental and theoretical results

SynopsisFragment energy spectra of the water molecule impacted by singly charged (SCI) and highly charged (HCI) ions have been measured in crossed beam experiments. Double differential fragmentation cross sections (DDCS) have been determined. Similarities and differences of the measured DDCSs induced by the medium- and low-energy projectiles have been analyzed. Multiple target ionization cross sections have been deduced and they were further analyzed through the results of the CTMC and CDW-EIS models.

Differential cross section measurements for hadron therapy: 50 MeV/nucleon C12 reactions on H, C, O, Al, and Tinat targets

During a carbon therapy treatment, the beam undergoes inelastic nuclear reactions leading to the production of secondary fragments. These nuclear interactions tend to delocate a part of the dose into healthy tissues and create a mixed radiation field. In order to accurately estimate the dose deposited into the tissues, the production rate of these fragments all along the beam path have to be taken into account. But the double differential carbon fragmentation cross sections are not well known in the energy range needed for a treatment (up to 400 MeV/nucleon). Therefore, a series of experiments aiming to measure the double differential fragmentation cross sections of carbon on thin targets of medical interest has been started by our collaboration. In March 2015 we performed an experiment to study the fragmentation of a 50 MeV/nucleon C12 beam on thin targets at GANIL. During this experiment, energy and angular cross-section distributions on H, C, O, Al, and Tinat have been measured. The experimental set-up will be detailed as well as the systematic error study and all the experimental results will be presented.

Differential cross-sections measurements for hadrontherapy: 50 MeV/A12C reactions on H, C, O, Al andnatTi targets

In order to keep the benefits of a carbon treatment, the dose and biological effects induced by secondary fragments must be taken into account when simulating the treatment plan. These Monte-Carlo simulations codes are done using nuclear models that are constrained by experimental data. It is hence necessary to have precise measurements of the production rates of these fragments all along the beam path and for its whole energy range. In this context, a series of experiments aiming to measure the double differential fragmentation cross-sections of carbon on thin targets of medical interest has been started by our collaboration. In March 2015, an experiment was performed with a 50 MeV/nucleon 12 C beam at GANIL. During this experiment, energy and angular differential cross-section distributions on H, C, O, Al and nat Ti have been measured. In the following, the experimental set-up and analysis process are briefly described and some experimental results are presented. Comparisons between several exit channel models from Phits and Geant4 show great discrepancies with the experimental data. Finally, the homemade Sliipie model is briefly presented and preliminary results are compared to the data with a promising outcome.

Erratum: Double-differential fragmentation cross-section measurements of 95 MeV/nucleonC12beams on thin targets for hadron therapy [Phys. Rev. C88, 024606 (2013)

Erratum: Double-differential fragmentation cross-section measurements of 95 MeV/nucleon<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi mathvariant="normal">C</mml:mi><mml:mprescripts /><mml:none /><mml:mrow><mml:mn>12</mml:mn></mml:mrow></mml:mmultiscripts></mml:math>beams on thin targets for hadron therapy [Phys. Rev. C<b>88</b>, 024606 (2013)

Carbon fragmentation measurements and validation of the Geant4 nuclear reaction models for hadrontherapy

Nuclear fragmentation measurements are necessary when using heavy-ion beams in hadrontherapy to predict the effects of the ion nuclear interactions within the human body. Moreover, they are also fundamental to validate and improve the Monte Carlo codes for their use in planning tumor treatments. Nowadays, a very limited set of carbon fragmentation cross sections are being measured, and in particular, to our knowledge, no double-differential fragmentation cross sections at intermediate energies are available in the literature. In this work, we have measured the double-differential cross sections and the angular distributions of the secondary fragments produced in the 12C fragmentation at 62 A MeV on a thin carbon target. The experimental data have been used to benchmark the prediction capability of the Geant4 Monte Carlo code at intermediate energies, where it was never tested before. In particular, we have compared the experimental data with the predictions of two Geant4 nuclear reaction models: the Binary Light Ions Cascade and the Quantum Molecular Dynamic. From the comparison, it has been observed that the Binary Light Ions Cascade approximates the angular distributions of the fragment production cross sections better than the Quantum Molecular Dynamic model. However, the discrepancies observed between the experimental data and the Monte Carlo simulations lead to the conclusion that the prediction capability of both models needs to be improved at intermediate energies.

Double differential fragmentation cross section measurements of H2n+1+ions,n⩽7

Pursuing previous integral fragmentation cross section measurements of hydrogen cluster ions with He as scattering partner [1], double differential fragmentation cross sections against Ar have been measured for ions in the mass range from H5 + to H15 +. The ions are formed by electron bombardment of neutral clusters in a nozzle beam and extracted from the ionizing region at an energy of 300 eV; directly in front of the scattering region they are decelerated to a laboratory energy E 0 between 6·8 and 75 eV. In the scattering region the primary (parent) ion beam is attenuated and fragment (daughter) ions are formed. The detection of the parent and daughter ions occurs as function of their laboratory deflection angle as well as their laboratory velocity. It is found that both the angle distribution and the velocity distribution broaden symmetrically with an increase of the number of H2 molecules lost in the fragmentation process. For example, at an energy E 0 = 6·8 eV the values for the full width at half ma...