The coupling of ultra-intense,ultra-short laser pulses with solid targets is heavily dependent on the properties of the vacuum–solid interface and is usually quite low.However,laser absorption can be enhanced via mic...The coupling of ultra-intense,ultra-short laser pulses with solid targets is heavily dependent on the properties of the vacuum–solid interface and is usually quite low.However,laser absorption can be enhanced via micro or nanopatterning of the target surface.Depending on the laser features and target geometry,conditions can be optimized for the generation of hot dense matter,which can be used to produce high-brightness radiation sources or even to accelerate particles to relativistic energies.In this context,ZnO nanowires were grown on metallic,thin-foil targets.The use of a thin-foil substrate was dictated by the need to achieve proton acceleration via target normal sheath acceleration at the rear side.The chemical process parameters were studied in-depth to provide control over the nanowire size,shape,and distribution.Moreover,the manufacturing process was optimized to provide accurate reproducibility of key parameters in the widest possible range and good homogeneity across the entire foil area.展开更多
Fast electron generation and transport in high-intensity laser–solid interactions induces X-ray emission and drives ion acceleration.Effective production of these sources hinges on an efficient laser absorption into ...Fast electron generation and transport in high-intensity laser–solid interactions induces X-ray emission and drives ion acceleration.Effective production of these sources hinges on an efficient laser absorption into the fast electron population and control of divergence as the beam propagates through the target.Nanowire targets can be employed to increase the laser absorption,but it is not yet clear how the fast electron beam properties are modified.Here we present novel measurements of the emittance of the exiting fast electron beam from irradiated solid planar and nanowire targets via a pepper-pot diagnostic.The measurements indicate a greater fast electron emittance is obtained from nanowire targets.Two-dimensional particle-in-cell simulations support this conclusion,revealing beam defocusing at the wire–substrate boundary,a higher fast electron temperature and transverse oscillatory motion around the wires.展开更多
文摘The coupling of ultra-intense,ultra-short laser pulses with solid targets is heavily dependent on the properties of the vacuum–solid interface and is usually quite low.However,laser absorption can be enhanced via micro or nanopatterning of the target surface.Depending on the laser features and target geometry,conditions can be optimized for the generation of hot dense matter,which can be used to produce high-brightness radiation sources or even to accelerate particles to relativistic energies.In this context,ZnO nanowires were grown on metallic,thin-foil targets.The use of a thin-foil substrate was dictated by the need to achieve proton acceleration via target normal sheath acceleration at the rear side.The chemical process parameters were studied in-depth to provide control over the nanowire size,shape,and distribution.Moreover,the manufacturing process was optimized to provide accurate reproducibility of key parameters in the widest possible range and good homogeneity across the entire foil area.
基金the NextGenerationEU(PNRR)Integrated Infrastructure Initiative in Photonic and Quantum Sciences(IPHOQS)(CUP B53C22001750006,ID D2B8D520,IR0000016)EuPRAXIA Advanced Photon Sources(EuAPS)(CUP I93C21000160006,IR0000030)+3 种基金funding from the Engineering and Physical Sciences Research Council(EP/L01663X/1)the Royal Society International Exchange(IES/R3/170248)Computing resources were provided by STFC Scientific Computing Department’s SCARF clusterfunded by the UK EPSRC(grants EP/G054950/1,EP/G056803/1,EP/G055165/1 and EP/M022463/1).
文摘Fast electron generation and transport in high-intensity laser–solid interactions induces X-ray emission and drives ion acceleration.Effective production of these sources hinges on an efficient laser absorption into the fast electron population and control of divergence as the beam propagates through the target.Nanowire targets can be employed to increase the laser absorption,but it is not yet clear how the fast electron beam properties are modified.Here we present novel measurements of the emittance of the exiting fast electron beam from irradiated solid planar and nanowire targets via a pepper-pot diagnostic.The measurements indicate a greater fast electron emittance is obtained from nanowire targets.Two-dimensional particle-in-cell simulations support this conclusion,revealing beam defocusing at the wire–substrate boundary,a higher fast electron temperature and transverse oscillatory motion around the wires.
