Caractérisation élémentaire par interrogation neutronique avec la technique de la particule associée

The EURITRACK inspection system, based on the associated particle technique, aims at detecting explosives and narcotics in cargo containers with 14 MeV neutrons produced by the D(T,)n reaction. Alpha particle and neutron are emitted almost back to back. Reactions induced by fast neutrons produce gamma rays which are detected in coincidence with the alpha particle to determine the neutron direction. Neutron time-of-flight allows to determine gamma-ray origin inside the container. Information concerning material composition is obtained by unfolding the gamma spectrum into elemental signatures using a database of elemental spectra (C, O, N, Fe…). Carbon, oxygen, and nitrogen count ratios are converted into chemical proportions to distinguish illicit and benign organic materials. Conversion factors based on Monte Carlo simulations have been calculated and validated experimentally, taking into account neutron slowing down and photon attenuation in cargo materials. Application to the elemental characterisation of radioactive wastes is also studied by numerical simulation, with shields and collimators to limit the background due to waste radiations.Le système EURITRACK, basé sur la technique de la particule associée, vise à détecter des explosifs et des drogues dans les conteneurs maritimes avec des neutrons de 14 MeV produits par la réaction D(T,)n. La particule alpha et le neutron sont émis environ à 180° l'un de l'autre. Les réactions induites par le neutron produisent des rayonnements gamma qui sont détectés en coïncidence avec la particule alpha pour déterminer la direction et le temps de vol neutronique, et ainsi remonter à l'origine des rayonnements gamma dans le conteneur. La composition chimique est obtenue par déconvolution du spectre gamma en signatures élémentaires (C, O, N, Fe,…). Les rapports des nombres de coups du carbone, de l'oxygène et de l'azote sont convertis en proportions chimiques, afin de distinguer les matières organiques bénignes et illicites, via des facteurs calculés par simulation Monte Carlo et validés expérimentalement. Ils prennent en compte la modération neutronique et l'atténuation photonique dans les marchandises transportées. L'application à la caractérisation élémentaire des déchets radioactifs est aussi étudiée par simulation, avec des écrans et collimateurs pour limiter le bruit dû à l'émission radiologique des colis

Identification of materials by an advanceded neutronic method.

Le système EURITRACK, basé sur la technique de la particule associée, vise à détecter des explosifs et des drogues dans les conteneurs maritimes avec des neutrons de 14 MeV produits par la réaction D(T,)n. La particule alpha et le neutron sont émis environ à 180° l'un de l'autre. Les réactions induites par le neutron produisent des rayonnements gamma qui sont détectés en coïncidence avec la particule alpha pour déterminer la direction et le temps de vol neutronique, et ainsi remonter à l'origine des rayonnements gamma dans le conteneur. La composition chimique est obtenue par déconvolution du spectre gamma en signatures élémentaires (C, O, N, Fe,…). Les rapports des nombres de coups du carbone, de l'oxygène et de l'azote sont convertis en proportions chimiques, afin de distinguer les matières organiques bénignes et illicites, via des facteurs calculés par simulation Monte Carlo et validés expérimentalement. Ils prennent en compte la modération neutronique et l'atténuation photonique dans les marchandises transportées. L'application à la caractérisation élémentaire des déchets radioactifs est aussi étudiée par simulation, avec des écrans et collimateurs pour limiter le bruit dû à l'émission radiologique des colis.The EURITRACK inspection system, based on the associated particle technique, aims at detecting explosives and narcotics in cargo containers with 14 MeV neutrons produced by the D(T,)n reaction. Alpha particle and neutron are emitted almost back to back. Reactions induced by fast neutrons produce gamma rays which are detected in coincidence with the alpha particle to determine the neutron direction. Neutron time-of-flight allows to determine gamma-ray origin inside the container. Information concerning material composition is obtained by unfolding the gamma spectrum into elemental signatures using a database of elemental spectra (C, O, N, Fe…). Carbon, oxygen, and nitrogen count ratios are converted into chemical proportions to distinguish illicit and benign organic materials. Conversion factors based on Monte Carlo simulations have been calculated and validated experimentally, taking into account neutron slowing down and photon attenuation in cargo materials. Application to the elemental characterisation of radioactive wastes is also studied by numerical simulation, with shields and collimators to limit the background due to waste radiations

Caractérisation élémentaire par interrogation neutronique avec la technique de la particule associée

Le système EURITRACK, basé sur la technique de la particule associée, vise à détecter des explosifs et des drogues dans les conteneurs maritimes avec des neutrons de 14 MeV produits par la réaction D(T, )n. La particule alpha et le neutron sont émis environ à 180 l'un de l'autre. Les réactions induites par le neutron produisent des rayonnements gamma qui sont détectés en coïncidence avec la particule alpha pour déterminer la direction et le temps de vol neutronique, et ainsi remonter à l'origine des rayonnements gamma dans le conteneur. La composition chimique est obtenue par déconvolution du spectre gamma en signatures élémentaires (C, O, N, Fe, ). Les rapports des nombres de coups du carbone, de l'oxygène et de l'azote sont convertis en proportions chimiques, afin de distinguer les matières organiques bénignes et illicites, via des facteurs calculés par simulation Monte Carlo et validés expérimentalement. Ils prennent en compte la modération neutronique et l'atténuation photonique dans les marchandises transportées. L'application à la caractérisation élémentaire des déchets radioactifs est aussi étudiée par simulation, avec des écrans et collimateurs pour limiter le bruit dû à l'émission radiologique des colis.The EURITRACK inspection system, based on the associated particle technique, aims at detecting explosives and narcotics in cargo containers with 14 MeV neutrons produced by the D(T, )n reaction. Alpha particle and neutron are emitted almost back to back. Reactions induced by fast neutrons produce gamma rays which are detected in coincidence with the alpha particle to determine the neutron direction. Neutron time-of-flight allows to determine gamma-ray origin inside the container. Information concerning material composition is obtained by unfolding the gamma spectrum into elemental signatures using a database of elemental spectra (C, O, N, Fe ). Carbon, oxygen, and nitrogen count ratios are converted into chemical proportions to distinguish illicit and benign organic materials. Conversion factors based on Monte Carlo simulations have been calculated and validated experimentally, taking into account neutron slowing down and photon attenuation in cargo materials. Application to the elemental characterisation of radioactive wastes is also studied by numerical simulation, with shields and collimators to limit the background due to waste radiations.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF

Monte Carlo simulation of high-level radioactive waste characterization with the associated particle technique

International audienceThe French Alternative Energies and Atomic Energy Commission (CEA) is conducting an R&D program to improve the characterization of long lived and medium activity radioactive waste packages with nondestructive nuclear measurements. Neutron interrogation with the Associated Particle Technique (APT), which brings 3D information about waste materials composition, was studied by numerical simulation with the MCNP computer code [1] and MODAR data analysis software [2]. The design of the system is first presented, especially shields and collimators used to limit the detectors count rate because of the intense gamma emission of the waste. The random background due to the neutron generator was also limited by a specific shield as recommended earlier [3]. Then the paper presents numerical simulations illustrating the ability of APT to characterize specific volumes of interest filled with different materials (iron, water, aluminum, PVC, oil) in different waste packages. Main limitations are also identified, such as neutron scattering in the dense, hydrogenous waste matrices. © 2013 Elsevier B.V.},author_keywords={Associated particle technique; Fast neutron interrogation; Radioactive waste characterization},keywords={3D information; Alternative energy; Associated particle techniques; Atomic energy commissions; Computer codes; Count rates; Data analysis softwares; Fast neutrons; Gamma emission; High level radioactive wastes; Monte Carlo Simulation; Neutron generators; Neutron interrogation; Non destructive; Nuclear measurement; Radioactive waste packages; Volumes of interests; Waste characterization; Waste matrices; Waste package, Aluminum; Characterization; Computer simulation; Inspection equipment; Monte Carlo methods; Neutron sources, Radioactive waste

Fast Monte Carlo simulator for the distribution of promptgamma emitters in protontherapy

International audiencePurpose: Real-time in vivo control of the ion range in a patient during protontherapy is a major challenge for Quality Assurance of treatments. A few years ago, prompt gamma rays have been investigated for beam range verification with proton1 and carbon ion beams2. Since then, several teams in the world have been progressing toward the construction of first clinical prototypes3,4,5. The imaging concept is usually designed and optimized with the help of Monte Carlo simulations (MC), which have become the gold standard for physical calculations especially for simulations of prompt gammas emitted by proton inelastic interaction in complex geometries. It remains however hindered by its slow statistical convergence

Chromatography and high-resolution mass spectrometry for the characterization of the degradation products of the photodegradation of amidosulfuron: An analytical approach.

Simulated sunlight irradiation causing degradation of amidosulfuron, a pyrimidinylsulfonylurea herbicide, has been investigated in aqueous solution. The main degradation products were followed up by ultrahigh-pressure liquid chromatography with a UV detector (UHPLC-UV) and identified by combining ultrahight-pressure liquid chromatography-mass spectrometry (UHPLC-MS) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). On the basis of the retrosynthetic analysis, the most identified degradation products were mainly due to the losses of methylsulfamic acid (CH5NO3S), sulfocarbamic acid (CH3NO5S), carbamic acid (CH3NO2), methyl(methylsulfonyl)sulfamic acid (C2H7NO5S2), N-methylmethanesulfonamide (C2H7NO2S), and sulfonic acid (H2SO4) molecules. Accordingly, O and S-demethylation as well as hydroxylation processes were also observed. Sum formulas of the main degradation products were assigned, and a mechanical pathway is proposed