Laser-produced plasma helium-like titanium Kα x-ray source and its application to Rayleigh-Taylor instability study

【摘要】 Several experiments are performed on the ShenGuang-II laser facility to investigate an x-ray source and test radiography concepts.X-ray lines emitted from laser-produced plasmas are the most practical means of generating these high intensity sources.By using a time-integrated space-resolved keV spectroscope and pinhole camera,potential helium-like titanium Kα x-ray backlighting (radiography) line source is studied as a function of laser wavelength,ratio of pre-pulse intensity to main pulse intensity,and laser intensity (from 7.25 to～11.3×10 15 W/cm 2).One-dimensional radiography using a grid consisting of 5 μm Au wires on 16 μm period and the pinhole-assisted point projection is tested.The measurements show that the size of the helium-like titanium Kα source from a simple foil target is larger than 100 μm,and relative x-ray line emission conversion efficiency ξ x from the incident laser light energy to heliumlike titanium K-shell spectrum increases significantly with pre-pulse intensity increasing,increases rapidly with laser wavelength decreasing,and increases moderately with main laser intensity increasing.It is also found that a gold gird foils can reach an imaging resolution better than 5-μm featured with high contrast.It is further demonstrated that the pinhole-assisted point projection at such a level will be a novel two-dimensional imaging diagnostic technique for inertial confinement fusion experiments.更多还原

【Abstract】 Several experiments are performed on the ShenGuang-II laser facility to investigate an x-ray source and test radiography concepts.X-ray lines emitted from laser-produced plasmas are the most practical means of generating these high intensity sources.By using a time-integrated space-resolved keV spectroscope and pinhole camera,potential helium-like titanium Kα x-ray backlighting (radiography) line source is studied as a function of laser wavelength,ratio of pre-pulse intensity to main pulse intensity,and laser intensity (from 7.25 to～11.3×10 15 W/cm 2).One-dimensional radiography using a grid consisting of 5 μm Au wires on 16 μm period and the pinhole-assisted point projection is tested.The measurements show that the size of the helium-like titanium Kα source from a simple foil target is larger than 100 μm,and relative x-ray line emission conversion efficiency ξ x from the incident laser light energy to heliumlike titanium K-shell spectrum increases significantly with pre-pulse intensity increasing,increases rapidly with laser wavelength decreasing,and increases moderately with main laser intensity increasing.It is also found that a gold gird foils can reach an imaging resolution better than 5-μm featured with high contrast.It is further demonstrated that the pinhole-assisted point projection at such a level will be a novel two-dimensional imaging diagnostic technique for inertial confinement fusion experiments.更多还原