11 research outputs found
In-Target ProtonâBoron Nuclear Fusion Using a PW-Class Laser
Nuclear reactions between protons and boron-11 nuclei (pâB fusion) that were used to yield energetic α-particles were initiated in a plasma that was generated by the interaction between a PW-class laser operating at relativistic intensities (~3 Ă 10^19 W/cm2) and a 0.2-mm thick boron nitride (BN) target. A high pâB fusion reaction rate and hence, a large α-particle flux was generated and measured, thanks to a proton stream accelerated at the targetâs front surface. This was the first proof of principle experiment to demonstrate the efficient generation of α-particles (~10^10/sr) through pâB fusion reactions using a PW-class laser in the âin-targetâ geometry
Generation of α-Particle Beams With a Multi-kJ, Peta-Watt Class Laser System
We present preliminary results on generation of energetic α-particles driven by lasers. The experiment was performed at the Institute of Laser Engineering in Osaka using the short-pulse, high-intensity, high-energy, PW-class laser. The laser pulse was focused onto a thin plastic foil (pitcher) to generate a proton beam by the well-known TNSA mechanism which, in turn, was impinging onto a boron-nitride (BN) target (catcher) to generated alpha-particles as a result of proton-boron nuclear fusion events. Our results demonstrate generation of α-particles with energies in the range 8â10 MeV and with a flux around 5 Ă 10^9 sr^â1
Laser driven ion acceleration by electrostatic shocks in gas jet targets and radioisotopes production.
La production de radioisotopes, notamment dâintĂ©rĂȘt mĂ©dical, est aujourdâhuiprincipalement assurĂ©e par des accĂ©lĂ©rateurs conventionnels circulaires: les cyclotrons. Cesisotopes radioactifs, une fois produits, sont injectĂ©s dans le corps du patient Ă des fins diag-nostique ou curative. Pour des radioisotopes Ă©metteurs Beta+, les positrons Ă©mis sâannihilenten deux gammas de façon instantannĂ©e par rĂ©action avec les Ă©lectrons de la matiĂšre. Cesdeux gammas Ă©mis Ă 180° sont dĂ©tectĂ©s en coincidence et permettent de remonter au pointdâĂ©mission du positron et ainsi de cartographier lâorgane du patient. Pour des radioisotopesĂ©metteurs Beta-, alpha et gamma, les rayonnements ionisants Ă©mis permettent quant Ă eux de traiter le patient en irradiant les cellules cancĂ©reuses.Les radioisotopes utilisĂ©s en mĂ©decine nuclĂ©aire doivent prĂ©senter une courte durĂ©e de vieafin de ne pas engendrer de dommages collatĂ©raux chez le patient. Cette courte durĂ©e de vieimpose de les produire directement dans les servives de mĂ©decine nuclĂ©aire pour les plus cou-rants (Fluor-18 en diagnostic) grĂące Ă des cyclotrons consĂ©quents en termes dâencombrementet dâinvestissement. Dâautres radioisotopes utilisĂ©s nĂ©cessitent des moyens de production en-core plus importants (cyclotron de type ARRONAX, rĂ©acteurs nuclĂ©aires pour le Technicium99) et doivent ĂȘtre livrĂ©s dans les hopitaux de façon rĂ©guliĂšre. Les dĂ©lais dâacheminement,les coĂ»ts de production et de maintenance des cyclotrons, le vieillissement des rĂ©acteursnuclĂ©aires, parallĂšlement au dĂ©veloppement continu des systĂšmes laser de haute puissanceet de haute intensitĂ©, ont amenĂ© Ă envisager la production de radioisotopes par laser. Eneffet, lâaccĂ©lĂ©ration dâions par laser permettrait dâabaisser les coĂ»ts de production mais aussidâobtenir un systĂšme beaucoup plus flexible quâun accĂ©lĂ©rateur conventionnel: en choisissantles cibles irradiĂ©es selon la gamme dâĂ©nergie du faisceau dâions obtenu par accĂ©lĂ©ration laser,la crĂ©ation de nombreux radioisotopes deviendrait possible avec un unique et mĂȘme systĂšme:lâaccĂ©lĂ©rateur laser.Lâobjectif de cette thĂšse est, dans un premier temps, dâoptimiser lâaccĂ©lĂ©ration dâionspar laser ultra haute intensitĂ©, notamment par choc Ă©lectrostatique dans les jets de gaz etdâexplorer la production de radioisotopes Ă lâaide de ce faisceau dâions dit primaire. Lâob-tention dâun faisceau dâions accĂ©lĂ©rĂ©s avec un nombre important dâions dans une certainegamme dâĂ©nergie est une Ă©tape cruciale dans le but de produire dâun radioisotope afin defaire correspondre le spectre Ă©nergĂ©tique de ce faisceau dâions avec les maxima des sectionsefficaces de production du radioisotope souhaitĂ©. La premiĂšre partie de cette thĂšse sâinscritdonc dans la production de ce type de faisceau dâions et son optimisation en termes denombre et dâĂ©nergie (avec un maximum dâions accĂ©lĂ©rĂ©s dans des structures de type quasimono-Ă©nergĂ©tiques). Lâutilisation de cibles gazeuses est privilĂ©giĂ©e dans ce travail puisqueces derniĂšres permettent de profiter des lasers Ă hauts taux de rĂ©pĂ©tition qui, eux seuls, per-mettront de concurrencer les cyclotrons en terme de courant pour le faisceau dâions primaire.Cette Ă©tude sâappuie sur des simulations numĂ©riques permettant de modĂ©liser lâaccĂ©lĂ©-ration dâions lors de lâinteraction du laser avec des cibles solides ou gazeuses (via un codeParticle-In-Cell) et la gĂ©nĂ©ration des radioisotopes lors de la propagation de ces ions dansune cible secondaire (via un code Monte Carlo). La production in situ de radioisotopes parĂ©clairement direct dâune cible est aussi Ă©tudiĂ©e Ă lâaide de ces deux types de codes. CesdĂ©veloppements numĂ©riques ont permis de dimensionner et dâanalyser des expĂ©riences surdes installations laser actuelles mais aussi de servir de base pour de futures expĂ©riences.The production of radioisotopes in relevance with the nuclear medecine community is nowadays warranted by cyclotrons. These radioisotopes, once produced, are injectedin the patient body for curative or diagnostics purpose. For ÎČ + emitters, the positron, reactingwith matter electrons, annihilates in two gamma photons. These two photons, emittedat 180_ are detected by coincidence and allow to know the exact position of the emissionpoint and to map the patient organ. For ÎČ - or α emitters, the ionizing radiation emitted isused to kill the cancer cells. The radioisotopes related to nuclear medecine have to present a short lifetime so as not to not drive collateral damages for the patient. Thus, a production closed to the nuclear medecine department is compulsory. This is the case for the Fluor-18 for example that is produced inside the hospitals by little cyclotrons. Other radioisotopes require more important means of production (cyclortron as ARRONAX in Nantes, nuclear power plants for the Tc-99) and have to be delivered every week to the nuclear medecine department. The delivery times, the hardware installation and maintenance costs added to the aging of nuclear reactors drive scientists to consider other facilities for radioisotopes production. The actual laser systems are known to accelerate ions from laser-plasma interaction. Actually, laser-driven ion acceleration is an attractive way to realize compact and affordable ion sources for many exciting applications, including to produce radioisotopes in relevance with the nuclear medecine community. We propose to use ion beams to produce radioisotopes in a secondary target. At first, we explore and optimize laser-driven ion acceleration, especially by collisionless electrostatic shocks in a gas jet. The solid targets are also considered in this work. This ion beam requires particular characteristics on its energy spectrum and its flux to produce radioisotopes in a secondary target. The ion energy distribution has to match the higher cross section values for the nuclear reaction producing the desired radioisotope. So the first part of this work consists of optimizing the production of an ion beam with a high flux and with a high energy. The use of gas jet targets is the best way to take advantage of high repetition rates laser systems since the final goal is to replace cyclotrons by a more flexible device: laser beam. A maximum of laser energy has to be transfered to the solid target or to the gas jet target in order to make the laser ion acceleration process more efficient. The acceleration efficiency depends on the target density profile (presence of a pre plasma in the solid target case or the gas jet wings) and on the acceleration mechanism. All these questions are studied in the first part of this manuscript. We propose to strongly improve the ion acceleration with maximum ion energy of tens of MeV thanks to the interaction of a relativistic laser pulse with a tailored gas jet target. The production of a beam of energetic alpha particles is studied in this work, from an helium jet target and also from the proton-boron fusion reaction. We present the numerical chain, that we developed at CELIA during this three-year research process, formed by an hydrodynamic code (TROLL [1] or CHIC [2]) that allows to simulate the interaction between the target and the laser pre-pulse, the Particle-In-Cell (PIC) code Smilei [3] for the interaction between the main pulse and the plasma, and the MONTE-CARLO code FLUKA [4] for the propagation of the ion beam in the secondary target and nuclear reactions that allow to produce radioisotopes. The results of radiosiotope production are analysed, in terms of ion acceleration mechanisms and of targets properties
Optimisation de lâaccĂ©lĂ©ration dâions par choc Ă©lectrostatique dans un jet de gaz et application Ă la production de radioisotopes
The production of radioisotopes in relevance with the nuclear medecine community is nowadays warranted by cyclotrons. These radioisotopes, once produced, are injectedin the patient body for curative or diagnostics purpose. For ÎČ + emitters, the positron, reactingwith matter electrons, annihilates in two gamma photons. These two photons, emittedat 180_ are detected by coincidence and allow to know the exact position of the emissionpoint and to map the patient organ. For ÎČ - or α emitters, the ionizing radiation emitted isused to kill the cancer cells. The radioisotopes related to nuclear medecine have to present a short lifetime so as not to not drive collateral damages for the patient. Thus, a production closed to the nuclear medecine department is compulsory. This is the case for the Fluor-18 for example that is produced inside the hospitals by little cyclotrons. Other radioisotopes require more important means of production (cyclortron as ARRONAX in Nantes, nuclear power plants for the Tc-99) and have to be delivered every week to the nuclear medecine department. The delivery times, the hardware installation and maintenance costs added to the aging of nuclear reactors drive scientists to consider other facilities for radioisotopes production. The actual laser systems are known to accelerate ions from laser-plasma interaction. Actually, laser-driven ion acceleration is an attractive way to realize compact and affordable ion sources for many exciting applications, including to produce radioisotopes in relevance with the nuclear medecine community. We propose to use ion beams to produce radioisotopes in a secondary target. At first, we explore and optimize laser-driven ion acceleration, especially by collisionless electrostatic shocks in a gas jet. The solid targets are also considered in this work. This ion beam requires particular characteristics on its energy spectrum and its flux to produce radioisotopes in a secondary target. The ion energy distribution has to match the higher cross section values for the nuclear reaction producing the desired radioisotope. So the first part of this work consists of optimizing the production of an ion beam with a high flux and with a high energy. The use of gas jet targets is the best way to take advantage of high repetition rates laser systems since the final goal is to replace cyclotrons by a more flexible device: laser beam. A maximum of laser energy has to be transfered to the solid target or to the gas jet target in order to make the laser ion acceleration process more efficient. The acceleration efficiency depends on the target density profile (presence of a pre plasma in the solid target case or the gas jet wings) and on the acceleration mechanism. All these questions are studied in the first part of this manuscript. We propose to strongly improve the ion acceleration with maximum ion energy of tens of MeV thanks to the interaction of a relativistic laser pulse with a tailored gas jet target. The production of a beam of energetic alpha particles is studied in this work, from an helium jet target and also from the proton-boron fusion reaction. We present the numerical chain, that we developed at CELIA during this three-year research process, formed by an hydrodynamic code (TROLL [1] or CHIC [2]) that allows to simulate the interaction between the target and the laser pre-pulse, the Particle-In-Cell (PIC) code Smilei [3] for the interaction between the main pulse and the plasma, and the MONTE-CARLO code FLUKA [4] for the propagation of the ion beam in the secondary target and nuclear reactions that allow to produce radioisotopes. The results of radiosiotope production are analysed, in terms of ion acceleration mechanisms and of targets properties.La production de radioisotopes, notamment dâintĂ©rĂȘt mĂ©dical, est aujourdâhuiprincipalement assurĂ©e par des accĂ©lĂ©rateurs conventionnels circulaires: les cyclotrons. Cesisotopes radioactifs, une fois produits, sont injectĂ©s dans le corps du patient Ă des fins diag-nostique ou curative. Pour des radioisotopes Ă©metteurs Beta+, les positrons Ă©mis sâannihilenten deux gammas de façon instantannĂ©e par rĂ©action avec les Ă©lectrons de la matiĂšre. Cesdeux gammas Ă©mis Ă 180° sont dĂ©tectĂ©s en coincidence et permettent de remonter au pointdâĂ©mission du positron et ainsi de cartographier lâorgane du patient. Pour des radioisotopesĂ©metteurs Beta-, alpha et gamma, les rayonnements ionisants Ă©mis permettent quant Ă eux de traiter le patient en irradiant les cellules cancĂ©reuses.Les radioisotopes utilisĂ©s en mĂ©decine nuclĂ©aire doivent prĂ©senter une courte durĂ©e de vieafin de ne pas engendrer de dommages collatĂ©raux chez le patient. Cette courte durĂ©e de vieimpose de les produire directement dans les servives de mĂ©decine nuclĂ©aire pour les plus cou-rants (Fluor-18 en diagnostic) grĂące Ă des cyclotrons consĂ©quents en termes dâencombrementet dâinvestissement. Dâautres radioisotopes utilisĂ©s nĂ©cessitent des moyens de production en-core plus importants (cyclotron de type ARRONAX, rĂ©acteurs nuclĂ©aires pour le Technicium99) et doivent ĂȘtre livrĂ©s dans les hopitaux de façon rĂ©guliĂšre. Les dĂ©lais dâacheminement,les coĂ»ts de production et de maintenance des cyclotrons, le vieillissement des rĂ©acteursnuclĂ©aires, parallĂšlement au dĂ©veloppement continu des systĂšmes laser de haute puissanceet de haute intensitĂ©, ont amenĂ© Ă envisager la production de radioisotopes par laser. Eneffet, lâaccĂ©lĂ©ration dâions par laser permettrait dâabaisser les coĂ»ts de production mais aussidâobtenir un systĂšme beaucoup plus flexible quâun accĂ©lĂ©rateur conventionnel: en choisissantles cibles irradiĂ©es selon la gamme dâĂ©nergie du faisceau dâions obtenu par accĂ©lĂ©ration laser,la crĂ©ation de nombreux radioisotopes deviendrait possible avec un unique et mĂȘme systĂšme:lâaccĂ©lĂ©rateur laser.Lâobjectif de cette thĂšse est, dans un premier temps, dâoptimiser lâaccĂ©lĂ©ration dâionspar laser ultra haute intensitĂ©, notamment par choc Ă©lectrostatique dans les jets de gaz etdâexplorer la production de radioisotopes Ă lâaide de ce faisceau dâions dit primaire. Lâob-tention dâun faisceau dâions accĂ©lĂ©rĂ©s avec un nombre important dâions dans une certainegamme dâĂ©nergie est une Ă©tape cruciale dans le but de produire dâun radioisotope afin defaire correspondre le spectre Ă©nergĂ©tique de ce faisceau dâions avec les maxima des sectionsefficaces de production du radioisotope souhaitĂ©. La premiĂšre partie de cette thĂšse sâinscritdonc dans la production de ce type de faisceau dâions et son optimisation en termes denombre et dâĂ©nergie (avec un maximum dâions accĂ©lĂ©rĂ©s dans des structures de type quasimono-Ă©nergĂ©tiques). Lâutilisation de cibles gazeuses est privilĂ©giĂ©e dans ce travail puisqueces derniĂšres permettent de profiter des lasers Ă hauts taux de rĂ©pĂ©tition qui, eux seuls, per-mettront de concurrencer les cyclotrons en terme de courant pour le faisceau dâions primaire.Cette Ă©tude sâappuie sur des simulations numĂ©riques permettant de modĂ©liser lâaccĂ©lĂ©-ration dâions lors de lâinteraction du laser avec des cibles solides ou gazeuses (via un codeParticle-In-Cell) et la gĂ©nĂ©ration des radioisotopes lors de la propagation de ces ions dansune cible secondaire (via un code Monte Carlo). La production in situ de radioisotopes parĂ©clairement direct dâune cible est aussi Ă©tudiĂ©e Ă lâaide de ces deux types de codes. CesdĂ©veloppements numĂ©riques ont permis de dimensionner et dâanalyser des expĂ©riences surdes installations laser actuelles mais aussi de servir de base pour de futures expĂ©riences
Optimisation de lâaccĂ©lĂ©ration dâions par choc Ă©lectrostatique dans un jet de gaz et application Ă la production de radioisotopes
The production of radioisotopes in relevance with the nuclear medecine community is nowadays warranted by cyclotrons. These radioisotopes, once produced, are injectedin the patient body for curative or diagnostics purpose. For ÎČ + emitters, the positron, reactingwith matter electrons, annihilates in two gamma photons. These two photons, emittedat 180_ are detected by coincidence and allow to know the exact position of the emissionpoint and to map the patient organ. For ÎČ - or α emitters, the ionizing radiation emitted isused to kill the cancer cells. The radioisotopes related to nuclear medecine have to present a short lifetime so as not to not drive collateral damages for the patient. Thus, a production closed to the nuclear medecine department is compulsory. This is the case for the Fluor-18 for example that is produced inside the hospitals by little cyclotrons. Other radioisotopes require more important means of production (cyclortron as ARRONAX in Nantes, nuclear power plants for the Tc-99) and have to be delivered every week to the nuclear medecine department. The delivery times, the hardware installation and maintenance costs added to the aging of nuclear reactors drive scientists to consider other facilities for radioisotopes production. The actual laser systems are known to accelerate ions from laser-plasma interaction. Actually, laser-driven ion acceleration is an attractive way to realize compact and affordable ion sources for many exciting applications, including to produce radioisotopes in relevance with the nuclear medecine community. We propose to use ion beams to produce radioisotopes in a secondary target. At first, we explore and optimize laser-driven ion acceleration, especially by collisionless electrostatic shocks in a gas jet. The solid targets are also considered in this work. This ion beam requires particular characteristics on its energy spectrum and its flux to produce radioisotopes in a secondary target. The ion energy distribution has to match the higher cross section values for the nuclear reaction producing the desired radioisotope. So the first part of this work consists of optimizing the production of an ion beam with a high flux and with a high energy. The use of gas jet targets is the best way to take advantage of high repetition rates laser systems since the final goal is to replace cyclotrons by a more flexible device: laser beam. A maximum of laser energy has to be transfered to the solid target or to the gas jet target in order to make the laser ion acceleration process more efficient. The acceleration efficiency depends on the target density profile (presence of a pre plasma in the solid target case or the gas jet wings) and on the acceleration mechanism. All these questions are studied in the first part of this manuscript. We propose to strongly improve the ion acceleration with maximum ion energy of tens of MeV thanks to the interaction of a relativistic laser pulse with a tailored gas jet target. The production of a beam of energetic alpha particles is studied in this work, from an helium jet target and also from the proton-boron fusion reaction. We present the numerical chain, that we developed at CELIA during this three-year research process, formed by an hydrodynamic code (TROLL [1] or CHIC [2]) that allows to simulate the interaction between the target and the laser pre-pulse, the Particle-In-Cell (PIC) code Smilei [3] for the interaction between the main pulse and the plasma, and the MONTE-CARLO code FLUKA [4] for the propagation of the ion beam in the secondary target and nuclear reactions that allow to produce radioisotopes. The results of radiosiotope production are analysed, in terms of ion acceleration mechanisms and of targets properties.La production de radioisotopes, notamment dâintĂ©rĂȘt mĂ©dical, est aujourdâhuiprincipalement assurĂ©e par des accĂ©lĂ©rateurs conventionnels circulaires: les cyclotrons. Cesisotopes radioactifs, une fois produits, sont injectĂ©s dans le corps du patient Ă des fins diag-nostique ou curative. Pour des radioisotopes Ă©metteurs Beta+, les positrons Ă©mis sâannihilenten deux gammas de façon instantannĂ©e par rĂ©action avec les Ă©lectrons de la matiĂšre. Cesdeux gammas Ă©mis Ă 180° sont dĂ©tectĂ©s en coincidence et permettent de remonter au pointdâĂ©mission du positron et ainsi de cartographier lâorgane du patient. Pour des radioisotopesĂ©metteurs Beta-, alpha et gamma, les rayonnements ionisants Ă©mis permettent quant Ă eux de traiter le patient en irradiant les cellules cancĂ©reuses.Les radioisotopes utilisĂ©s en mĂ©decine nuclĂ©aire doivent prĂ©senter une courte durĂ©e de vieafin de ne pas engendrer de dommages collatĂ©raux chez le patient. Cette courte durĂ©e de vieimpose de les produire directement dans les servives de mĂ©decine nuclĂ©aire pour les plus cou-rants (Fluor-18 en diagnostic) grĂące Ă des cyclotrons consĂ©quents en termes dâencombrementet dâinvestissement. Dâautres radioisotopes utilisĂ©s nĂ©cessitent des moyens de production en-core plus importants (cyclotron de type ARRONAX, rĂ©acteurs nuclĂ©aires pour le Technicium99) et doivent ĂȘtre livrĂ©s dans les hopitaux de façon rĂ©guliĂšre. Les dĂ©lais dâacheminement,les coĂ»ts de production et de maintenance des cyclotrons, le vieillissement des rĂ©acteursnuclĂ©aires, parallĂšlement au dĂ©veloppement continu des systĂšmes laser de haute puissanceet de haute intensitĂ©, ont amenĂ© Ă envisager la production de radioisotopes par laser. Eneffet, lâaccĂ©lĂ©ration dâions par laser permettrait dâabaisser les coĂ»ts de production mais aussidâobtenir un systĂšme beaucoup plus flexible quâun accĂ©lĂ©rateur conventionnel: en choisissantles cibles irradiĂ©es selon la gamme dâĂ©nergie du faisceau dâions obtenu par accĂ©lĂ©ration laser,la crĂ©ation de nombreux radioisotopes deviendrait possible avec un unique et mĂȘme systĂšme:lâaccĂ©lĂ©rateur laser.Lâobjectif de cette thĂšse est, dans un premier temps, dâoptimiser lâaccĂ©lĂ©ration dâionspar laser ultra haute intensitĂ©, notamment par choc Ă©lectrostatique dans les jets de gaz etdâexplorer la production de radioisotopes Ă lâaide de ce faisceau dâions dit primaire. Lâob-tention dâun faisceau dâions accĂ©lĂ©rĂ©s avec un nombre important dâions dans une certainegamme dâĂ©nergie est une Ă©tape cruciale dans le but de produire dâun radioisotope afin defaire correspondre le spectre Ă©nergĂ©tique de ce faisceau dâions avec les maxima des sectionsefficaces de production du radioisotope souhaitĂ©. La premiĂšre partie de cette thĂšse sâinscritdonc dans la production de ce type de faisceau dâions et son optimisation en termes denombre et dâĂ©nergie (avec un maximum dâions accĂ©lĂ©rĂ©s dans des structures de type quasimono-Ă©nergĂ©tiques). Lâutilisation de cibles gazeuses est privilĂ©giĂ©e dans ce travail puisqueces derniĂšres permettent de profiter des lasers Ă hauts taux de rĂ©pĂ©tition qui, eux seuls, per-mettront de concurrencer les cyclotrons en terme de courant pour le faisceau dâions primaire.Cette Ă©tude sâappuie sur des simulations numĂ©riques permettant de modĂ©liser lâaccĂ©lĂ©-ration dâions lors de lâinteraction du laser avec des cibles solides ou gazeuses (via un codeParticle-In-Cell) et la gĂ©nĂ©ration des radioisotopes lors de la propagation de ces ions dansune cible secondaire (via un code Monte Carlo). La production in situ de radioisotopes parĂ©clairement direct dâune cible est aussi Ă©tudiĂ©e Ă lâaide de ces deux types de codes. CesdĂ©veloppements numĂ©riques ont permis de dimensionner et dâanalyser des expĂ©riences surdes installations laser actuelles mais aussi de servir de base pour de futures expĂ©riences
Laser driven ion acceleration by electrostatic shocks in gas jet targets and radioisotopes production.
La production de radioisotopes, notamment dâintĂ©rĂȘt mĂ©dical, est aujourdâhuiprincipalement assurĂ©e par des accĂ©lĂ©rateurs conventionnels circulaires: les cyclotrons. Cesisotopes radioactifs, une fois produits, sont injectĂ©s dans le corps du patient Ă des fins diag-nostique ou curative. Pour des radioisotopes Ă©metteurs Beta+, les positrons Ă©mis sâannihilenten deux gammas de façon instantannĂ©e par rĂ©action avec les Ă©lectrons de la matiĂšre. Cesdeux gammas Ă©mis Ă 180° sont dĂ©tectĂ©s en coincidence et permettent de remonter au pointdâĂ©mission du positron et ainsi de cartographier lâorgane du patient. Pour des radioisotopesĂ©metteurs Beta-, alpha et gamma, les rayonnements ionisants Ă©mis permettent quant Ă eux de traiter le patient en irradiant les cellules cancĂ©reuses.Les radioisotopes utilisĂ©s en mĂ©decine nuclĂ©aire doivent prĂ©senter une courte durĂ©e de vieafin de ne pas engendrer de dommages collatĂ©raux chez le patient. Cette courte durĂ©e de vieimpose de les produire directement dans les servives de mĂ©decine nuclĂ©aire pour les plus cou-rants (Fluor-18 en diagnostic) grĂące Ă des cyclotrons consĂ©quents en termes dâencombrementet dâinvestissement. Dâautres radioisotopes utilisĂ©s nĂ©cessitent des moyens de production en-core plus importants (cyclotron de type ARRONAX, rĂ©acteurs nuclĂ©aires pour le Technicium99) et doivent ĂȘtre livrĂ©s dans les hopitaux de façon rĂ©guliĂšre. Les dĂ©lais dâacheminement,les coĂ»ts de production et de maintenance des cyclotrons, le vieillissement des rĂ©acteursnuclĂ©aires, parallĂšlement au dĂ©veloppement continu des systĂšmes laser de haute puissanceet de haute intensitĂ©, ont amenĂ© Ă envisager la production de radioisotopes par laser. Eneffet, lâaccĂ©lĂ©ration dâions par laser permettrait dâabaisser les coĂ»ts de production mais aussidâobtenir un systĂšme beaucoup plus flexible quâun accĂ©lĂ©rateur conventionnel: en choisissantles cibles irradiĂ©es selon la gamme dâĂ©nergie du faisceau dâions obtenu par accĂ©lĂ©ration laser,la crĂ©ation de nombreux radioisotopes deviendrait possible avec un unique et mĂȘme systĂšme:lâaccĂ©lĂ©rateur laser.Lâobjectif de cette thĂšse est, dans un premier temps, dâoptimiser lâaccĂ©lĂ©ration dâionspar laser ultra haute intensitĂ©, notamment par choc Ă©lectrostatique dans les jets de gaz etdâexplorer la production de radioisotopes Ă lâaide de ce faisceau dâions dit primaire. Lâob-tention dâun faisceau dâions accĂ©lĂ©rĂ©s avec un nombre important dâions dans une certainegamme dâĂ©nergie est une Ă©tape cruciale dans le but de produire dâun radioisotope afin defaire correspondre le spectre Ă©nergĂ©tique de ce faisceau dâions avec les maxima des sectionsefficaces de production du radioisotope souhaitĂ©. La premiĂšre partie de cette thĂšse sâinscritdonc dans la production de ce type de faisceau dâions et son optimisation en termes denombre et dâĂ©nergie (avec un maximum dâions accĂ©lĂ©rĂ©s dans des structures de type quasimono-Ă©nergĂ©tiques). Lâutilisation de cibles gazeuses est privilĂ©giĂ©e dans ce travail puisqueces derniĂšres permettent de profiter des lasers Ă hauts taux de rĂ©pĂ©tition qui, eux seuls, per-mettront de concurrencer les cyclotrons en terme de courant pour le faisceau dâions primaire.Cette Ă©tude sâappuie sur des simulations numĂ©riques permettant de modĂ©liser lâaccĂ©lĂ©-ration dâions lors de lâinteraction du laser avec des cibles solides ou gazeuses (via un codeParticle-In-Cell) et la gĂ©nĂ©ration des radioisotopes lors de la propagation de ces ions dansune cible secondaire (via un code Monte Carlo). La production in situ de radioisotopes parĂ©clairement direct dâune cible est aussi Ă©tudiĂ©e Ă lâaide de ces deux types de codes. CesdĂ©veloppements numĂ©riques ont permis de dimensionner et dâanalyser des expĂ©riences surdes installations laser actuelles mais aussi de servir de base pour de futures expĂ©riences.The production of radioisotopes in relevance with the nuclear medecine community is nowadays warranted by cyclotrons. These radioisotopes, once produced, are injectedin the patient body for curative or diagnostics purpose. For ÎČ + emitters, the positron, reactingwith matter electrons, annihilates in two gamma photons. These two photons, emittedat 180_ are detected by coincidence and allow to know the exact position of the emissionpoint and to map the patient organ. For ÎČ - or α emitters, the ionizing radiation emitted isused to kill the cancer cells. The radioisotopes related to nuclear medecine have to present a short lifetime so as not to not drive collateral damages for the patient. Thus, a production closed to the nuclear medecine department is compulsory. This is the case for the Fluor-18 for example that is produced inside the hospitals by little cyclotrons. Other radioisotopes require more important means of production (cyclortron as ARRONAX in Nantes, nuclear power plants for the Tc-99) and have to be delivered every week to the nuclear medecine department. The delivery times, the hardware installation and maintenance costs added to the aging of nuclear reactors drive scientists to consider other facilities for radioisotopes production. The actual laser systems are known to accelerate ions from laser-plasma interaction. Actually, laser-driven ion acceleration is an attractive way to realize compact and affordable ion sources for many exciting applications, including to produce radioisotopes in relevance with the nuclear medecine community. We propose to use ion beams to produce radioisotopes in a secondary target. At first, we explore and optimize laser-driven ion acceleration, especially by collisionless electrostatic shocks in a gas jet. The solid targets are also considered in this work. This ion beam requires particular characteristics on its energy spectrum and its flux to produce radioisotopes in a secondary target. The ion energy distribution has to match the higher cross section values for the nuclear reaction producing the desired radioisotope. So the first part of this work consists of optimizing the production of an ion beam with a high flux and with a high energy. The use of gas jet targets is the best way to take advantage of high repetition rates laser systems since the final goal is to replace cyclotrons by a more flexible device: laser beam. A maximum of laser energy has to be transfered to the solid target or to the gas jet target in order to make the laser ion acceleration process more efficient. The acceleration efficiency depends on the target density profile (presence of a pre plasma in the solid target case or the gas jet wings) and on the acceleration mechanism. All these questions are studied in the first part of this manuscript. We propose to strongly improve the ion acceleration with maximum ion energy of tens of MeV thanks to the interaction of a relativistic laser pulse with a tailored gas jet target. The production of a beam of energetic alpha particles is studied in this work, from an helium jet target and also from the proton-boron fusion reaction. We present the numerical chain, that we developed at CELIA during this three-year research process, formed by an hydrodynamic code (TROLL [1] or CHIC [2]) that allows to simulate the interaction between the target and the laser pre-pulse, the Particle-In-Cell (PIC) code Smilei [3] for the interaction between the main pulse and the plasma, and the MONTE-CARLO code FLUKA [4] for the propagation of the ion beam in the secondary target and nuclear reactions that allow to produce radioisotopes. The results of radiosiotope production are analysed, in terms of ion acceleration mechanisms and of targets properties
In-Target ProtonâBoron Nuclear Fusion Using a PW-Class Laser
none15siNuclear reactions between protons and boron-11 nuclei (pâB fusion) that were used to yield energetic α-particles were initiated in a plasma that was generated by the interaction between a PW-class laser operating at relativistic intensities (~3 Ă 1019 W/cm2) and a 0.2-mm thick boron nitride (BN) target. A high pâB fusion reaction rate and hence, a large α-particle flux was generated and measured, thanks to a proton stream accelerated at the targetâs front surface. This was the first proof of principle experiment to demonstrate the efficient generation of α-particles (~1010/sr) through pâB fusion reactions using a PW-class laser in the âin-targetâ geometry.noneDaniele Margarone, Julien Bonvalet , Lorenzo Giuffrida, Alessio Morace , Vasiliki Kantarelou , Marco Tosca, Didier Raffestin, Philippe Nicolai, Antonino Picciotto, Yuki Abe, Yasunobu Arikawa, Shinsuke Fujioka, Yuji Fukuda, Yasuhiro Kuramitsu, Hideaki Habara and Dimitri Batani.Margarone, Daniele; Bonvalet, Julien; Giuffrida, Lorenzo; Morace, Alessio; Kantarelou, Vasiliki; Tosca, Marco; Raffestin, Didier; Nicolai, Philippe; Picciotto, Antonino; Abe, Yuki; Arikawa, Yasunobu; Fujioka, Shinsuke; Fukuda, Yuji; Kuramitsu, Yasuhiro; Batani., Hideaki Habara and Dimitr
Generation of α-Particle Beams With a Multi-kJ, Peta-Watt Class Laser System
We present preliminary results on generation of energetic α-particles driven by lasers. The experiment was performed at the Institute of Laser Engineering in Osaka using the short-pulse, high-intensity, high-energy, PW-class laser. The laser pulse was focused onto a thin plastic foil (pitcher) to generate a proton beam by the well-known TNSA mechanism which, in turn, was impinging onto a boron-nitride (BN) target (catcher) to generated alpha-particles as a result of proton-boron nuclear fusion events. Our results demonstrate generation of α-particles with energies in the range 8â10 MeV and with a flux around 5 Ă 109 srâ1
Intestinal Akkermansia muciniphila predicts clinical response to PD-1 blockade in patients with advanced non-small-cell lung cancer
43siAside from PD-L1 expression, biomarkers of response to immune checkpoint inhibitors (ICIs) in non-small-cell lung cancer (NSCLC) are needed. In a previous retrospective analysis, we documented that fecal Akkermansia muciniphila (Akk) was associated with clinical benefit of ICI in patients with NSCLC or kidney cancer. In the current study, we performed shotgun-metagenomics-based microbiome profiling in a large cohort of patients with advanced NSCLC (n = 338) treated with first- or second-line ICIs to prospectively validate the predictive value of fecal Akk. Baseline stool Akk was associated with increased objective response rates and overall survival in multivariate analyses, independent of PD-L1 expression, antibiotics, and performance status. Intestinal Akk was accompanied by a richer commensalism, including Eubacterium hallii and Bifidobacterium adolescentis, and a more inflamed tumor microenvironment in a subset of patients. However, antibiotic use (20% of cases) coincided with a relative dominance of Akk above 4.8% accompanied with the genus Clostridium, both associated with resistance to ICI. Our study shows significant differences in relative abundance of Akk that may represent potential biomarkers to refine patient stratification in future studies.reservedopenDerosa, Lisa; Routy, Bertrand; Thomas, Andrew Maltez; Iebba, Valerio; Zalcman, Gerard; Friard, Sylvie; Mazieres, Julien; Audigier-Valette, Clarisse; Moro-Sibilot, Denis; Goldwasser, François; Silva, Carolina Alves Costa; Terrisse, Safae; Bonvalet, Melodie; Scherpereel, Arnaud; Pegliasco, Hervé; Richard, Corentin; Ghiringhelli, François; Elkrief, Arielle; Desilets, Antoine; Blanc-Durand, Felix; Cumbo, Fabio; Blanco, Aitor; Boidot, Romain; Chevrier, Sandy; DaillÚre, Romain; Kroemer, Guido; Alla, Laurie; Pons, Nicolas; Le Chatelier, Emmanuelle; Galleron, Nathalie; Roume, Hugo; Dubuisson, Agathe; Bouchard, Nicole; Messaoudene, Meriem; Drubay, Damien; Deutsch, Eric; Barlesi, Fabrice; Planchard, David; Segata, Nicola; Martinez, Stéphanie; Zitvogel, Laurence; Soria, Jean-Charles; Besse, BenjaminDerosa, Lisa; Routy, Bertrand; Thomas, Andrew Maltez; Iebba, Valerio; Zalcman, Gerard; Friard, Sylvie; Mazieres, Julien; Audigier-Valette, Clarisse; Moro-Sibilot, Denis; Goldwasser, François; Silva, Carolina Alves Costa; Terrisse, Safae; Bonvalet, Melodie; Scherpereel, Arnaud; Pegliasco, Hervé; Richard, Corentin; Ghiringhelli, François; Elkrief, Arielle; Desilets, Antoine; Blanc-Durand, Felix; Cumbo, Fabio; Blanco, Aitor; Boidot, Romain; Chevrier, Sandy; DaillÚre, Romain; Kroemer, Guido; Alla, Laurie; Pons, Nicolas; Le Chatelier, Emmanuelle; Galleron, Nathalie; Roume, Hugo; Dubuisson, Agathe; Bouchard, Nicole; Messaoudene, Meriem; Drubay, Damien; Deutsch, Eric; Barlesi, Fabrice; Planchard, David; Segata, Nicola; Martinez, Stéphanie; Zitvogel, Laurence; Soria, Jean-Charles; Besse, Benjami