Inelastic scattering of electron and light ion beams in organic polymers

Vera, Pablo de; Abril, Isabel; García-Molina, Rafael

doi:10.1063/1.3581120

Cited by 55 publications

(49 citation statements)

References 61 publications

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“…Our present results of ionization potential are compared with available previous work for dry DNA (I= 81.02 eV) [8] good agreement is achieved in previous work [16]. [25] 75 [9] 77.01 PMMA 68.37 [9] 74 [9] 79.55 H2O 72.5 [9] 75 [9] 76.32…”

Section: Resultssupporting

confidence: 76%

“…N: is the number of bound electrons and q is charge state of the projectile inside the target can be change through capture and loss processes. When charge equilibrium is reached, the probability of finding the projectile in charge state remains constant for each incident energy T [16]. (8) where the charge-state fractions, , which do not only depend on the projectile energy, but also on its nature as well as on the target characteristics, are obtained from a parameterization to the experimental equilibrium charge fractions [17].…”

Section: Probability Per Unite Lengthmentioning

confidence: 99%

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Proton Impact of Bimolecular Targets

Khalaf¹,

Ahmad²,

Al-Ani³

2017

Journal of Asian Scientific Research

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Article HistoryFor a better control and understanding of the effects of radiation damage in living tissues by using the irradiation of biological systems by energetic ion beams have multiple applications in medical physics and space radiation health, such as hadron therapy for cancer treatment and it is necessary to advance an accurate description of the energy loss from the ion beam to the target. In the present work the dielectric formalism like Drude has been used to calculate the probability for an energetic proton and to produce electronic excitations in five targets of high biological interest, namely, liquid water, DNA, PMMA, Adenine and Guanine. Also, the effects of ionization fraction on the mean excitation energy, average energy and Inelastic mean free path studied taking in to consideration electronic excitation in the target. Good agreement achieved with previous work. Contribution/ Originality:This study document an empirical method of obtaining the energy loss function which is the key quantity to study the energy deposited in targets of biological interest by swift projectiles such as protons, so it contains all the information about the electron excitation spectrum of the target.,. The model used through (ELF), namely the extended-Drude ELF. Each term in the sum of Drude-type functions has three adjustable parameters. The parameters a, b and c can be obtained by a fit of Eq. (1) to the ELF for compounds. The energy delivered by a swift proton beam in materials of interest to hadron therapy in 5 compounds is investigated.

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Section: Resultssupporting

confidence: 76%

Section: Probability Per Unite Lengthmentioning

confidence: 99%

Proton Impact of Bimolecular Targets

Khalaf¹,

Ahmad²,

Al-Ani³

2017

Journal of Asian Scientific Research

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“…Symbols represent a compilation of reference data [35], while the dotted line are GEANT4-DNA Monte Carlo calculation results [36]. The solid and dashed lines give the CSDA ranges calculated using equation (8) and the electronic stopping powers obtained from the dielectric formalism (as explained in references [37,38], although in this case using the extended-Drude method, as explained, e.g., in reference [8], accurate enough for high energies), employing a thermalisation energy of 45 and 7 eV, respectively. The decrease of the threshold energy produces an increase of the CSDA range.…”

Section: Accounting For δ-Electronsmentioning

confidence: 99%

Radial doses around energetic ion tracks and the onset of shock waves on the nanoscale

et al. 2017

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Abstract. Energetic ions lose their energy in tissue mainly by ionising its molecules. This produces secondary electrons which transport this energy radially away from the ion path. The ranges of most of these electrons do not exceed a few nanometres, therefore large energy densities (radial doses) are produced within a narrow region around the ion trajectory. Large energy density gradients correspond to large pressure gradients and this brings about shock waves propagating away from the ion path. Previous works have studied these waves by molecular dynamics (MD) simulations investigating their damaging effects on DNA molecules. However, these simulations where performed assuming that all energy lost by ions is deposited uniformly in thin cylinders around their path. In the present work, the radial dose distributions, calculated by solving the diffusion equation for the low energy electrons and complemented with a semi-empirical inclusion of more energetic δ-electrons, are used to set up initial conditions for the shock wave simulation. The effect of these energy distributions vs. stepwise energy distributions in tracks on the strength of shock waves induced by carbon ions both in the Bragg peak region and out of it is studied by MD simulations.

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“…In Table I the I values for all the materials treated in this work are 13 presented, which are calculated using the MELF-GOS method [de Vera et al, 2011, 14 Abril et al, 2012. 15 16 Simulations with the SEICS code indicate that electronic interactions is the major 1 responsible of the energy loss of the projectile, so the stopping power determines 2 mainly the position of the Bragg peak, whereas the energy-loss straggling is the major 3 responsible of its shape .…”

Section: F T F T T V T T V T T V T C Mmentioning

confidence: 99%