A pulsed fast neutron source is critical for applications of fast neutron resonance radiography and fast neutron absorption spectroscopy.However,due to the large transversal source size(of the order of mm)and long pul...A pulsed fast neutron source is critical for applications of fast neutron resonance radiography and fast neutron absorption spectroscopy.However,due to the large transversal source size(of the order of mm)and long pulse duration(of the order of ns)of traditional pulsed fast neutron sources,it is difficult to realize high-contrast neutron imaging with high spatial resolution and a fine absorption spectrum.Here,we experimentally present a micro-size ultra-short pulsed neutron source by a table-top laser-plasma wakefield electron accelerator driving a photofission reaction in a thin metal converter.A fast neutron source with source size of approximately 500μm and duration of approximately 36 ps has been driven by a tens of MeV,collimated,micro-size electron beam via a hundred TW laser facility.This micro-size ultra-short pulsed neutron source has the potential to improve the energy resolution of a fast neutron absorption spectrum dozens of times to,for example,approximately 100 eV at 1.65 MeV,which could be of benefit for high-quality fast neutron imaging and deep understanding of the theoretical model of neutron physics.展开更多
The temporal profiles of high-power short-pulse lasers reflected from self-induced plasma mirrors(PMs)were measured with high temporal resolution in the sub-picosecond window.The leading front shape of the laser pulse...The temporal profiles of high-power short-pulse lasers reflected from self-induced plasma mirrors(PMs)were measured with high temporal resolution in the sub-picosecond window.The leading front shape of the laser pulse is found to depend sensitively on the laser fluence on the PM surface.Spectral modulation plays a key role in pulse profile shaping.Our findings will extend our knowledge on properly using PMs.展开更多
The influence of second-order dispersion(SOD)on stimulated Raman scattering(SRS)in the interaction of an ultrashort intense laser with plasma was investigated.More significant backward SRS was observed with the increa...The influence of second-order dispersion(SOD)on stimulated Raman scattering(SRS)in the interaction of an ultrashort intense laser with plasma was investigated.More significant backward SRS was observed with the increase of the absolute value of SOD(|ψ2|).The integrated intensity of the scattered light is positively correlated to the driver laser pulse duration.Accompanied by the side SRS,filaments with different angles along the laser propagation direction were observed in the transverse shadowgraph.A model incorporating Landau damping and above-threshold ionization was developed to explain the SOD-dependent angular distribution of the filaments.展开更多
A dual-beam platform is developed for all-optical Thomson/Compton scattering,with versatile parameter tuning capabilities including electron energy,radiation energy,radiation polarization,etc.By integrating this platf...A dual-beam platform is developed for all-optical Thomson/Compton scattering,with versatile parameter tuning capabilities including electron energy,radiation energy,radiation polarization,etc.By integrating this platform with a 200 TW Ti:sapphire laser system,we demonstrate the generation of inverse Compton scattering X-/gamma-rays with tunable energies ranging from tens of keV to MeV.The polarization of X-/gamma-rays is manipulated by adjusting the polarization of the scattering laser.In the near future,by combining this platform with multi-PW laser facilities,our goal is to explore the transition from nonlinear Thomson scattering to nonlinear Compton scattering,ultimately verifying theories related to strong-field quantum electrodynamics effects induced by extreme scattering.展开更多
基金supported by the Science Challenge Project(No.TZ2018005)the National Natural Science Foundation of China(Nos.11875191,11991073,11890710,and 11721404)+2 种基金the Strategic Priority Research Program of the CAS(Nos.XDB1602 and XDA01020304)the Key Program of CAS(Nos.XDA01020304 and XDB17030500)the National Key R&D Program of China(No.2017YFA0403301)。
文摘A pulsed fast neutron source is critical for applications of fast neutron resonance radiography and fast neutron absorption spectroscopy.However,due to the large transversal source size(of the order of mm)and long pulse duration(of the order of ns)of traditional pulsed fast neutron sources,it is difficult to realize high-contrast neutron imaging with high spatial resolution and a fine absorption spectrum.Here,we experimentally present a micro-size ultra-short pulsed neutron source by a table-top laser-plasma wakefield electron accelerator driving a photofission reaction in a thin metal converter.A fast neutron source with source size of approximately 500μm and duration of approximately 36 ps has been driven by a tens of MeV,collimated,micro-size electron beam via a hundred TW laser facility.This micro-size ultra-short pulsed neutron source has the potential to improve the energy resolution of a fast neutron absorption spectrum dozens of times to,for example,approximately 100 eV at 1.65 MeV,which could be of benefit for high-quality fast neutron imaging and deep understanding of the theoretical model of neutron physics.
基金supported by the National Basic Research Program of China(No.2013CBA01502)the National Natural Science Foundation of China(Nos.11721091,11205100,and 11305103)the National Key Scientific Instrument Development Project(No.2012YQ030142)
文摘The temporal profiles of high-power short-pulse lasers reflected from self-induced plasma mirrors(PMs)were measured with high temporal resolution in the sub-picosecond window.The leading front shape of the laser pulse is found to depend sensitively on the laser fluence on the PM surface.Spectral modulation plays a key role in pulse profile shaping.Our findings will extend our knowledge on properly using PMs.
基金supported by NSAF(No.U1930111)of Chinathe Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA25030200).
文摘The influence of second-order dispersion(SOD)on stimulated Raman scattering(SRS)in the interaction of an ultrashort intense laser with plasma was investigated.More significant backward SRS was observed with the increase of the absolute value of SOD(|ψ2|).The integrated intensity of the scattered light is positively correlated to the driver laser pulse duration.Accompanied by the side SRS,filaments with different angles along the laser propagation direction were observed in the transverse shadowgraph.A model incorporating Landau damping and above-threshold ionization was developed to explain the SOD-dependent angular distribution of the filaments.
基金supported by the National Key R&D Program of China (Grant No.2021YFA1601700)the National Natural Science Foundation of China (Grant Nos.12074251,11991073,12335016,12105174 and 12225505)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant Nos.XDA25030400 and XDA25010100)the sponsorship from the Yangyang Development Fund
文摘A dual-beam platform is developed for all-optical Thomson/Compton scattering,with versatile parameter tuning capabilities including electron energy,radiation energy,radiation polarization,etc.By integrating this platform with a 200 TW Ti:sapphire laser system,we demonstrate the generation of inverse Compton scattering X-/gamma-rays with tunable energies ranging from tens of keV to MeV.The polarization of X-/gamma-rays is manipulated by adjusting the polarization of the scattering laser.In the near future,by combining this platform with multi-PW laser facilities,our goal is to explore the transition from nonlinear Thomson scattering to nonlinear Compton scattering,ultimately verifying theories related to strong-field quantum electrodynamics effects induced by extreme scattering.
