arXiv subjects

M. Labalme

Publications and source records attributed to M. Labalme.

6 recordsLinked to original sources

arXiv2014

Zero degree measurements of 12C fragmentation at 95 MeV/nucleon on thin targets

During therapeutic treatments using ions such as carbon, nuclear interactions between the incident ions and nuclei present in organic tissues may occur, leading to the attenuation of the incident beam intensity and to the production of secondary light charged particles. As the biological dose deposited in the tumor and the surrounding healthy tissues depends on the beam composition, an accurate knowledge of the fragmentation processes is thus essential. In particular, the nuclear interaction models have to be validated using experimental double differential cross sections which are still very scarce. An experiment was realized in 2011 at GANIL to obtain these cross sections for a 95 MeV/nucleon carbon beam on different thin targets for angles raging from 4 to 43{\deg} . In order to complete these data, a new experiment was performed on September 2013 at GANIL to measure the fragmentation cross section at zero degree for a 95 MeV/nucleon carbon beam on thin targets. In this work, the experimental setup will be described, the analysis method detailed and the results presented.

nucl-ex↗

arXiv2013

Simulation study on light ions identification methods for carbon beams from 95 to 400 MeV/A

Monte Carlo simulations have been performed in order to evaluate the efficiencies of several light ions identification techniques. The detection system was composed with layers of scintillating material to measure either the deposited energy or the time-of-flight of ions produced by nuclear reactions between 12C projectiles and a PMMA target. Well known techniques such as (DELTA) E--Range, (DELTA) E--E--ToF and (DELTA)E--E are presented and their particle identification efficiencies are compared one to another regarding the generated charge and mass of the particle to be identified. The simulations allowed to change the beam energy matching the ones proposed in an hadron therapy facility, namely from 95 to 400 MeV/A.

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arXiv2013

Benchmarking GEANT4 nuclear models for hadron therapy with 95 MeV/nucleon carbon ions

In carbon-therapy, the interaction of the incoming beam with human tissues may lead to the production of a large amount of nuclear fragments and secondary light particles. An accurate estimation of the biological dose deposited into the tumor and the surrounding healthy tissues thus requires sophisticated simulation tools based on nuclear reaction models. The validity of such models requires intensive comparisons with as many sets of experimental data as possible. Up to now, a rather limited set of double di erential carbon fragmentation cross sections have been measured in the energy range used in hadrontherapy (up to 400 MeV/A). However, new data have been recently obtained at intermediate energy (95 MeV/A). The aim of this work is to compare the reaction models embedded in the GEANT4 Monte Carlo toolkit with these new data. The strengths and weaknesses of each tested model, i.e. G4BinaryLightIonReaction, G4QMDReaction and INCL++, coupled to two di fferent de-excitation models, i.e. the generalized evaporation model and the Fermi break-up are discussed.

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arXiv2013

Double di ffential fragmentation cross sections measurements of 95 MeV/u 12C on thin targets for hadrontherapy

During therapeutic treatment with heavy ions like carbon, the beam undergoes nuclear fragmentation and secondary light charged particles, in particular protons and alpha particles, are produced. To estimate the dose deposited into the tumors and the surrounding healthy tissues, an accurate prediction on the fluences of these secondary fragments is necessary. Nowadays, a very limited set of double di ffential carbon fragmentation cross sections are being measured in the energy range used in hadrontherapy (40 to 400 MeV/u). Therefore, new measurements are performed to determine the double di ffential cross section of carbon on di erent thin targets. This work describes the experimental results of an experiment performed on May 2011 at GANIL. The double di ffential cross sections and the angular distributions of secondary fragments produced in the 12C fragmentation at 95 MeV/u on thin targets (C, CH2, Al, Al2O3, Ti and PMMA) have been measured. The experimental setup will be precisely described, the systematic error study will be explained and all the experimental data will be presented.

nucl-ex↗

arXiv2013

Comparison of two analysis methods for nuclear reaction measurements of 12C +12C interactions at 95 MeV/u for hadrontherapy

During therapeutic treatment with heavier ions like carbon, the beam undergoes nuclear fragmentation and secondary light charged particles, in particular protons and alpha particles, are produced. To estimate the dose deposited into the tumors and the surrounding healthy tissues, the accuracy must be higher than ($\pm$3% and$\pm$1 mm). Therefore, measurements are performed to determine the double differential cross section for different reactions. In this paper, the analysis of data from 12C +12C reactions at 95 MeV/u are presented. The emitted particles are detected with \DeltaEthin-\DeltaEthick-E telescopes made of a stack of two silicon detectors and a CsI crystal. Two different methods are used to identify the particles. One is based on graphical cuts onto the \DeltaE-E maps, the second is based on the so-called KaliVeda method using a functional description of \DeltaE versus E. The results of the two methods will be presented in this paper as well as the comparison between both.

physics.med-ph↗

arXiv2008

Paul trapping of radioactive 6He+ions and direct observation of their beta-decay

We demonstrate that abundant quantities of short-lived beta unstable ions can be trapped in a novel transparent Paul trap and that their decay products can directly be detected in coincidence. Low energy 6He+ (807 ms half-life) ions were extracted from the SPIRAL source at GANIL, then decelerated, cooled and bunched by means of the buffer gas cooling technique. More than 10^8 ions have been stored over a measuring period of six days and about 10^5 decay coincidences between the beta particles and the 6Li^{++} recoiling ions have been recorded. The technique can be extended to other short-lived species, opening new possibilities for trap assisted decay experiments.

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