Speaker
Description
Summary
Reliable nuclear fragmentation models are of utmost importance in hadron-therapy, where Monte Carlo (MC) simulations are used to compute the input parameters of the treatment planning software, to validate the deposited dose calculation, to evaluate the biological effectiveness of the radiation, to correlate the $\beta^+$ emitters production in the patient body with the delivered dose, and to allow a non-invasive treatment verification.
Despite of its large use, the models implemented in Geant4 have shown severe limitations in reproducing the measured secondary yields in ions interaction below 100 MeV/n, in term of production rates, angular and energy distributions [1, 2, 3].
For this reason, we coupled BLOB (Boltzmann-Langevin One Body) [4, 5], a model developed to simulate for such interactions, with Geant4 and its de-excitation phase.
We will present the preliminary results obtained in calculating double-differential cross sections and angular distributions of the secondary fragments produced in the $^{12}$C fragmentation at 62 MeV/n on thin carbon target obtained with these models and Geant4.
BLOB is a semi-classical one-body approaches to solve the Boltzmann-Langevin equation. It includes the propagation of a self-consistent mean-field, on the basis of an effective interaction. BLOB introduces fluctuations in full phase space through a collision term where nucleon-nucleon correlations are explicitly involved. It takes into account two-body interaction terms.
A simple coalescence between the produced nucleon has been implemented in between BLOB and the Geant4 de-excitation, to improve the agreement with experimental data on small fragments, up to alpha-particles, production.
BLOB, has been developed to simulate the heavy ion interactions in the Fermi-energy regime. We will show its capabilities in describing $^{12}$C fragmentation, with the coalescence and coupled with the Geant4 de-excitation model, foreseen its implementation in Geant4.
[1] B. Braunn et al. “Comparisons of hadrontherapy-relevant data to nuclear interaction codes in the Geant4 toolkit,” J. Phys.: Conf. Ser., 2013, vol. 420, p. 012163
[2] M. De Napoli et al. “Carbon fragmentation measurements and validation of the Geant4 nuclear reaction models for hadrontherapy,” Phys. Med. Biol., 2012, vol. 57, no. 22, pp. 7651–7671.
[3] J. Dudouet et al. “Benchmarking geant4 nuclear models for hadron therapy with 95 MeV/nucleon carbon ions,” Phys. Rev. C, 2014, vol. 89, no. 5, p. 054616.
[4] M. Colonna et al. “Fluctuations and dynamical instabilities in heavy-ion reactions,” Nucl. Phys., 1998, vol. A642, p. 449
[5] P. Napolitani and M. Colonna “Bifurcations in Boltzmann-Langevin one body dynamics for fermionic systems”, 2013, Phys. Lett. B vol. 726, pp. 382-386
