Ultrabright femtosecond X-ray pulses generated by X-ray free-electron lasers(XFELs)enable the high-resolution determination of nanoparticle structures without crystallization or freezing.As each particle that interact...Ultrabright femtosecond X-ray pulses generated by X-ray free-electron lasers(XFELs)enable the high-resolution determination of nanoparticle structures without crystallization or freezing.As each particle that interacts with the pulse is destroyed,an aerodynamic lens(ADL)is used to update the particles by focusing them into a narrow beam in real time.Current single-particle imaging(SPI)experiments are limited by an insufficient number of diffraction patterns;therefore,optimized ADLs are required to improve the hit rate and signal-to-noise ratio,particularly for small particles.Herein,an efficient and simple method for designing ADLs and a new ADL specifically designed for SPI using this method are presented.A new method is proposed based on the functional relationship between a key parameter and its influencing parameters in the ADL,which is established through theoretical analysis and numerical simulations.A detailed design process for the new ADL is also introduced.Both simulations and experiments are performed to characterize the behavior of the particles in the ADL.The results show that particles with diameters ranging from 30 to 500 nm can be effectively focused into a narrow beam.In particular,particles smaller than 100 nm exhibit better performance at lower flow rates than the injector currently used in SPI.The new ADL increases the beam density and reduces the gas background noise.This new method facilitates the design of ADLs for SPI and has potential applications in other fields that utilize focused aerosol beams.展开更多
基金supported by the Major State Basic Research Development Program of China(No.2022YFA1603703)Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB 37040303)+1 种基金National Natural Science Foundation of China(No.12335020)Shanghai Soft X-ray Free Electron Laser Facility beamline project.
文摘Ultrabright femtosecond X-ray pulses generated by X-ray free-electron lasers(XFELs)enable the high-resolution determination of nanoparticle structures without crystallization or freezing.As each particle that interacts with the pulse is destroyed,an aerodynamic lens(ADL)is used to update the particles by focusing them into a narrow beam in real time.Current single-particle imaging(SPI)experiments are limited by an insufficient number of diffraction patterns;therefore,optimized ADLs are required to improve the hit rate and signal-to-noise ratio,particularly for small particles.Herein,an efficient and simple method for designing ADLs and a new ADL specifically designed for SPI using this method are presented.A new method is proposed based on the functional relationship between a key parameter and its influencing parameters in the ADL,which is established through theoretical analysis and numerical simulations.A detailed design process for the new ADL is also introduced.Both simulations and experiments are performed to characterize the behavior of the particles in the ADL.The results show that particles with diameters ranging from 30 to 500 nm can be effectively focused into a narrow beam.In particular,particles smaller than 100 nm exhibit better performance at lower flow rates than the injector currently used in SPI.The new ADL increases the beam density and reduces the gas background noise.This new method facilitates the design of ADLs for SPI and has potential applications in other fields that utilize focused aerosol beams.
