The discovery of chirped pulse amplification has led to great improvements in laser technology,enabling energetic laser beams to be compressed to pulse durations of tens of femtoseconds and focused to a few micrometer...The discovery of chirped pulse amplification has led to great improvements in laser technology,enabling energetic laser beams to be compressed to pulse durations of tens of femtoseconds and focused to a few micrometers.Protons with energies of tens of MeV can be accelerated using,for instance,target normal sheath acceleration and focused on secondary targets.Under such conditions,nuclear reactions can occur,with the production of radioisotopes suitable for medical application.The use of high-repetition lasers to produce such isotopes is competitive with conventional methods mostly based on accelerators.In this paper,we study the production of^(67)Cu,^(63)Zn,^(18)F,and^(11)C,which are currently used in positron emission tomography and other applications.At the same time,we study the reactions^(10)B(p,α)^(7)Be and^(70)Zn(p,4n)^(67)Ga to put further constraints on the proton distributions at different angles,as well as the reaction^(11)B(p,α)^(8)Be relevant for energy production.The experiment was performed at the 1 PW laser facility at VegaⅢin Salamanca,Spain.Angular distributions of radioisotopes in the forward(with respect to the laser direction)and backward directions were measured using a high purity germanium detector.Our results are in reasonable agreement with numerical estimates obtained following the approach of Kimura and Bonasera[Nucl.Instrum.Methods Phys.Res.,Sect.A 637,164–170(2011)].展开更多
Driving of the nuclear fusion reaction p+^(11)B3α+8.7 MeV under laboratory conditions by interaction between high-power laser pulses and matter has become a popular field of research,owing to its numerous potential a...Driving of the nuclear fusion reaction p+^(11)B3α+8.7 MeV under laboratory conditions by interaction between high-power laser pulses and matter has become a popular field of research,owing to its numerous potential applications:as an alternative to deuterium-tritium for fusion energy production,astrophysics studies,and alpha-particle generation for medical treatment.One possible scheme for laser-driven p-^(11)B reactions is to direct a beam of laser-accelerated protons onto a boron(B)sample(the so-called“pitcher-catcher”scheme).This technique has been successfully implemented on large high-energy lasers,yielding hundreds of joules per shot at low repetition.We present here a complementary approach,exploiting the high repetition rate of the VEGA III petawatt laser at CLPU(Spain),aiming at accumulating results from many interactions at much lower energy,to provide better control of the parameters and the statistics of the measurements.Despite a moderate energy per pulse,our experiment allowed exploration of the laser-driven fusion process with tens(up to hundreds)of laser shots.The experiment provided a clear signature of the reactions involved and of the fusion products,accumulated over many shots,leading to an improved optimization of the diagnostics for experimental campaigns of this type.In this paper,we discuss the effectiveness of laser-driven p-11B fusion in the pitcher-catcher scheme,at a high repetition rate,addressing the challenges of this experimental scheme and highlighting its critical aspects.Our proposed methodology allows evaluation of the performance of this scheme for laser-driven alpha particle production and can be adapted to high-repetition-rate laser facilities with higher energy and intensity.展开更多
Large-amplitude electromagnetic radiofrequency fields are created by the charge-separation induced in interactions of high-intensity,short-pulse lasers with solid targets and have intensity that decreases with the dis...Large-amplitude electromagnetic radiofrequency fields are created by the charge-separation induced in interactions of high-intensity,short-pulse lasers with solid targets and have intensity that decreases with the distance from the target.Alternatively,it was experimentally proved very recently that charged particles emitted by petawatt laser±target interactions can be deposited on a capacitor-collector structure,far away from the target,and lead to the rapid(nanosecond-scale)generation of large quasi-static electric fields(MV/m),over wide regions.We demonstrate here the generation of both these fields in experiments at the PHELIX laser facility,with approximately 20 J energy and approximately 10^(19)W/cm^(2)intensity,for picoseconds laser pulses,interacting with pre-ionized polymer foams of near critical density.Quasi-static fields,up to tens of k V/m,were here observed at distances larger than 1 m from the target,with results much higher than the radiofrequency component.This is of primary importance for inertial-confinement fusion and laser±plasma acceleration and also for promising applications in different scenarios.展开更多
Understanding the physics of electromagnetic pulse(EMP) emission and nozzle damage is critical for the long-term operation of laser experiments with gas targets, particularly at facilities looking to produce stable so...Understanding the physics of electromagnetic pulse(EMP) emission and nozzle damage is critical for the long-term operation of laser experiments with gas targets, particularly at facilities looking to produce stable sources of radiation at high repetition rates. We present a theoretical model of plasma formation and electrostatic charging when high-power lasers are focused inside gases. The model can be used to estimate the amplitude of gigahertz EMPs produced by the laser and the extent of damage to the gas jet nozzle. Looking at a range of laser and target properties relevant to existing high-power laser systems, we find that EMP fields of tens to hundreds of kV/m can be generated several metres from the gas jet. Model predictions are compared with measurements of EMPs, plasma formation and nozzle damage from two experiments on the VEGA-3 laser and one experiment on the Vulcan Petawatt laser.展开更多
文摘The discovery of chirped pulse amplification has led to great improvements in laser technology,enabling energetic laser beams to be compressed to pulse durations of tens of femtoseconds and focused to a few micrometers.Protons with energies of tens of MeV can be accelerated using,for instance,target normal sheath acceleration and focused on secondary targets.Under such conditions,nuclear reactions can occur,with the production of radioisotopes suitable for medical application.The use of high-repetition lasers to produce such isotopes is competitive with conventional methods mostly based on accelerators.In this paper,we study the production of^(67)Cu,^(63)Zn,^(18)F,and^(11)C,which are currently used in positron emission tomography and other applications.At the same time,we study the reactions^(10)B(p,α)^(7)Be and^(70)Zn(p,4n)^(67)Ga to put further constraints on the proton distributions at different angles,as well as the reaction^(11)B(p,α)^(8)Be relevant for energy production.The experiment was performed at the 1 PW laser facility at VegaⅢin Salamanca,Spain.Angular distributions of radioisotopes in the forward(with respect to the laser direction)and backward directions were measured using a high purity germanium detector.Our results are in reasonable agreement with numerical estimates obtained following the approach of Kimura and Bonasera[Nucl.Instrum.Methods Phys.Res.,Sect.A 637,164–170(2011)].
基金funded by the European Union via the Euratom Research and Training Program(Grant Agreement No.101052200-EUROfusion)funding from LASERLAB-EUROPE(Grant Agreement No.871124,European Union’s Horizon 2020 Research and Innovation Program)+5 种基金supported in part by the United States Department of Energy under Grant No.DE-FG02-93ER40773We also acknowledge support from Grant No.PID2021-125389OA-I00 funded by MCIN/AEI/10.13039/501100011033/FEDER,UEby“ERDF A Way of Making Europe”by the European Union and Unidad de Investigación Consolidada of Junta de Castilla y León UIC 167supported in part by the National Natural Science Foundation of China under Grant No.12375125the Fundamental Research Funds for the Central Universitiesthe support of the Czech Science Foundation through Grant No.GACR24-11398S.
文摘Driving of the nuclear fusion reaction p+^(11)B3α+8.7 MeV under laboratory conditions by interaction between high-power laser pulses and matter has become a popular field of research,owing to its numerous potential applications:as an alternative to deuterium-tritium for fusion energy production,astrophysics studies,and alpha-particle generation for medical treatment.One possible scheme for laser-driven p-^(11)B reactions is to direct a beam of laser-accelerated protons onto a boron(B)sample(the so-called“pitcher-catcher”scheme).This technique has been successfully implemented on large high-energy lasers,yielding hundreds of joules per shot at low repetition.We present here a complementary approach,exploiting the high repetition rate of the VEGA III petawatt laser at CLPU(Spain),aiming at accumulating results from many interactions at much lower energy,to provide better control of the parameters and the statistics of the measurements.Despite a moderate energy per pulse,our experiment allowed exploration of the laser-driven fusion process with tens(up to hundreds)of laser shots.The experiment provided a clear signature of the reactions involved and of the fusion products,accumulated over many shots,leading to an improved optimization of the diagnostics for experimental campaigns of this type.In this paper,we discuss the effectiveness of laser-driven p-11B fusion in the pitcher-catcher scheme,at a high repetition rate,addressing the challenges of this experimental scheme and highlighting its critical aspects.Our proposed methodology allows evaluation of the performance of this scheme for laser-driven alpha particle production and can be adapted to high-repetition-rate laser facilities with higher energy and intensity.
基金funding from the Euratom research and training programs 2014-2018 and 2019-2020 under grant agreement No.633053funding from LASERLAB EUROPE(grant agreement No.654148,European Union’s Horizon 2020 research and innovation program)supported by the Ministry of Science and Higher Education of the Russian Federation(Agreement with Joint Institute for High Temperatures RAS No.075-15-2020-785,dated September 23,2020)。
文摘Large-amplitude electromagnetic radiofrequency fields are created by the charge-separation induced in interactions of high-intensity,short-pulse lasers with solid targets and have intensity that decreases with the distance from the target.Alternatively,it was experimentally proved very recently that charged particles emitted by petawatt laser±target interactions can be deposited on a capacitor-collector structure,far away from the target,and lead to the rapid(nanosecond-scale)generation of large quasi-static electric fields(MV/m),over wide regions.We demonstrate here the generation of both these fields in experiments at the PHELIX laser facility,with approximately 20 J energy and approximately 10^(19)W/cm^(2)intensity,for picoseconds laser pulses,interacting with pre-ionized polymer foams of near critical density.Quasi-static fields,up to tens of k V/m,were here observed at distances larger than 1 m from the target,with results much higher than the radiofrequency component.This is of primary importance for inertial-confinement fusion and laser±plasma acceleration and also for promising applications in different scenarios.
基金funded by the European Union via the Euratom Research and Training Programme(Grant Agreement No.101052200–EUROfusion)funded by MCIN/AEI/10.13039/501100011033/FEDER+4 种基金funded by the European Unionsupport from the LIGHT S&T Graduate Program(PIA3Investment for the Future Program,ANR-17-EURE-0027)funding from the European Union’s Horizon 2020 research and innovation programme through the European IMPULSE project under grant agreement No.871161 and from LASERLAB-EUROPE V under grant agreement No.871124co-financed by the Polish Ministry of Science and Higher Education within the framework of the scientific financial resources for 2021–2022 under contract No.5205/CELIA/2021/0(project CNRS No.239915)the financial support of the Id Ex University of Bordeaux/Grand Research Program‘GPR LIGHT’
文摘Understanding the physics of electromagnetic pulse(EMP) emission and nozzle damage is critical for the long-term operation of laser experiments with gas targets, particularly at facilities looking to produce stable sources of radiation at high repetition rates. We present a theoretical model of plasma formation and electrostatic charging when high-power lasers are focused inside gases. The model can be used to estimate the amplitude of gigahertz EMPs produced by the laser and the extent of damage to the gas jet nozzle. Looking at a range of laser and target properties relevant to existing high-power laser systems, we find that EMP fields of tens to hundreds of kV/m can be generated several metres from the gas jet. Model predictions are compared with measurements of EMPs, plasma formation and nozzle damage from two experiments on the VEGA-3 laser and one experiment on the Vulcan Petawatt laser.
