Optical vortices have the main features of helical wavefronts and spiral phase structures,and carry orbital angular momentum.This special structure of visible light has been produced and studied for various applicatio...Optical vortices have the main features of helical wavefronts and spiral phase structures,and carry orbital angular momentum.This special structure of visible light has been produced and studied for various applications.These notable characteristics of photons were also tested in the extreme-ultraviolet and X-ray regimes.In this article,we simulate the use of a simple afterburner configuration by directly adding helical undulators after the SASE undulators with the Shanghai Soft X-ray FEL to generate high intensity X-ray vortices with wavelengths^1 nm.Compared to other methods,this approach is easier to implement,cost-effective,and more efficient.展开更多
166.6-MHz quarter-waveβ=1 superconducting cavities have been adopted for the High Energy Photon Source,a 6-GeV diffraction-limited synchrotron light source currently under construction.A large helium jacket was requi...166.6-MHz quarter-waveβ=1 superconducting cavities have been adopted for the High Energy Photon Source,a 6-GeV diffraction-limited synchrotron light source currently under construction.A large helium jacket was required to accommodate the enlarged cavity beam pipe for the heavy damping of higher-order modes;the original electric-probe pickup thus becomes inevitably long with unfavorable mechanical properties.Relocated to an existing high-pressure-rinsing port,a magnetic-loop pickup was designed,characterized by low radio-frequency and cryogenic losses and being multipacting-free and insensitive to manufacturing and assembly tolerances.The consequent removal of the original pickup port from the cavity largely simplified the helium jacket fabrication and may also reduce cavity contamination.This paper presents a comprehensive design of a low-loss magnetic-coupling pickup for quarter-waveβ=1 superconducting cavities.The design can also be applied to other non-elliptical structures.展开更多
Technology based on high-peak-power lasers has the potential to provide compact and intense radiation sources for a wide range of innovative applications.In particular,electrons that are accelerated in the wakefield o...Technology based on high-peak-power lasers has the potential to provide compact and intense radiation sources for a wide range of innovative applications.In particular,electrons that are accelerated in the wakefield of an intense laser pulse oscillate around the propagation axis and emit X-rays.This betatron source,which essentially reproduces the principle of a synchrotron at the millimeter scale,provides bright radiation with femtosecond duration and high spatial coherence.However,despite its unique features,the usability of the betatron source has been constrained by its poor control and stability.In this article,we demonstrate the reliable production of X-ray beams with tunable polarization.Using ionization-induced injection in a gas mixture,the orbits of the relativistic electrons emitting the radiation are reproducible and controlled.We observe that both the signal and beam profile fluctuations are significantly reduced and that the beam pointing varies by less than a tenth of the beam divergence.The polarization ratio reaches 80%,and the polarization axis can easily be rotated.We anticipate a broad impact of the source,as its unprecedented performance opens the way for new applications.展开更多
Purpose High Energy Photon Source(HEPS)has the characteristics of high energy and low emittance,which requires that the 1st natural frequency of the magnet support assembly should be better than 54 Hz and the moving r...Purpose High Energy Photon Source(HEPS)has the characteristics of high energy and low emittance,which requires that the 1st natural frequency of the magnet support assembly should be better than 54 Hz and the moving resolution of girder should be less than 5μm.The prototypes have been designed and fabricated to meet the requirements.Methods In the design process of the support system model,double-wedge adjusting mechanism and concrete plinth construction are adopted to meet the requirements of adjusting resolution and stability.The FEA and the dynamic stiffness testing technique are used to verify the rationality of the design model.The stability and motion performance tests are performed to verify that the prototype meets the design requirements.Results Experimental results showthat,in all cases,the lowest first-order natural frequency of the support system is 55Hz,the amplification between magnet and ground is less than 1.05 in the directions perpendicular to the beam,the moving resolution can reach 1μm,and the girder can be locked in place with an error of less than 5μm.Conclusion The prototype of HEPS support system meets the requirements of stability and motion performance.The girder body and wedge mechanism made with iron or steel have little influence on the stability of the support system.The accuracy of dynamic stiffness test and finite element simulation results is verified.Further test will be performed in the HEPS site to verify the performance.展开更多
This paper presents the state of art of laser technologies in Poland. A list of primary laser technology development centers is included. The involvement of Polish scientists in the development of lasers and fourth ge...This paper presents the state of art of laser technologies in Poland. A list of primary laser technology development centers is included. The involvement of Polish scientists in the development of lasers and fourth generation synchrotron light sources as well as their applications is discussed. The development of laser applications in medical therapy and diagnostics, material micro- and macro-processing as well as environmental monitoring and protection, safety, and security is presented.展开更多
基金supported by the National Development and Reform Commission(20132347)National Basic Research Program of China(No.2015CB859700)。
文摘Optical vortices have the main features of helical wavefronts and spiral phase structures,and carry orbital angular momentum.This special structure of visible light has been produced and studied for various applications.These notable characteristics of photons were also tested in the extreme-ultraviolet and X-ray regimes.In this article,we simulate the use of a simple afterburner configuration by directly adding helical undulators after the SASE undulators with the Shanghai Soft X-ray FEL to generate high intensity X-ray vortices with wavelengths^1 nm.Compared to other methods,this approach is easier to implement,cost-effective,and more efficient.
基金supported by High Energy Photon Source(HEPS)projecta major national science and technology infrastructure。
文摘166.6-MHz quarter-waveβ=1 superconducting cavities have been adopted for the High Energy Photon Source,a 6-GeV diffraction-limited synchrotron light source currently under construction.A large helium jacket was required to accommodate the enlarged cavity beam pipe for the heavy damping of higher-order modes;the original electric-probe pickup thus becomes inevitably long with unfavorable mechanical properties.Relocated to an existing high-pressure-rinsing port,a magnetic-loop pickup was designed,characterized by low radio-frequency and cryogenic losses and being multipacting-free and insensitive to manufacturing and assembly tolerances.The consequent removal of the original pickup port from the cavity largely simplified the helium jacket fabrication and may also reduce cavity contamination.This paper presents a comprehensive design of a low-loss magnetic-coupling pickup for quarter-waveβ=1 superconducting cavities.The design can also be applied to other non-elliptical structures.
基金the Agence Nationale pour la Recherche through the FENICS Project No.ANR-12-JS04-0004-01the Agence Nationale pour la Recherche through the FEMTOMAT Project No.ANR-13-BS04-0002+4 种基金the X-Five project(Contract No.339128)the LUCELX project(ANR-13-BS04-0011)the EuCARD2/ANAC2 EC FP7 project(Contract No.312453)the GARC project 15-03118Ssupport from the European Union’s Horizon 2020 research and innovation program under Grant Agreement No.654148 Laserlab-Europe.
文摘Technology based on high-peak-power lasers has the potential to provide compact and intense radiation sources for a wide range of innovative applications.In particular,electrons that are accelerated in the wakefield of an intense laser pulse oscillate around the propagation axis and emit X-rays.This betatron source,which essentially reproduces the principle of a synchrotron at the millimeter scale,provides bright radiation with femtosecond duration and high spatial coherence.However,despite its unique features,the usability of the betatron source has been constrained by its poor control and stability.In this article,we demonstrate the reliable production of X-ray beams with tunable polarization.Using ionization-induced injection in a gas mixture,the orbits of the relativistic electrons emitting the radiation are reproducible and controlled.We observe that both the signal and beam profile fluctuations are significantly reduced and that the beam pointing varies by less than a tenth of the beam divergence.The polarization ratio reaches 80%,and the polarization axis can easily be rotated.We anticipate a broad impact of the source,as its unprecedented performance opens the way for new applications.
基金supported by the National Key Research and Development Program of China (2016YFB0700404)the National Natural Science Foundation of China (91860109,U2032205, 51671154, and 51927801)the support from the International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies and the Collaborative Innovation Center of High-End Manufacturing Equipment
文摘Purpose High Energy Photon Source(HEPS)has the characteristics of high energy and low emittance,which requires that the 1st natural frequency of the magnet support assembly should be better than 54 Hz and the moving resolution of girder should be less than 5μm.The prototypes have been designed and fabricated to meet the requirements.Methods In the design process of the support system model,double-wedge adjusting mechanism and concrete plinth construction are adopted to meet the requirements of adjusting resolution and stability.The FEA and the dynamic stiffness testing technique are used to verify the rationality of the design model.The stability and motion performance tests are performed to verify that the prototype meets the design requirements.Results Experimental results showthat,in all cases,the lowest first-order natural frequency of the support system is 55Hz,the amplification between magnet and ground is less than 1.05 in the directions perpendicular to the beam,the moving resolution can reach 1μm,and the girder can be locked in place with an error of less than 5μm.Conclusion The prototype of HEPS support system meets the requirements of stability and motion performance.The girder body and wedge mechanism made with iron or steel have little influence on the stability of the support system.The accuracy of dynamic stiffness test and finite element simulation results is verified.Further test will be performed in the HEPS site to verify the performance.
文摘This paper presents the state of art of laser technologies in Poland. A list of primary laser technology development centers is included. The involvement of Polish scientists in the development of lasers and fourth generation synchrotron light sources as well as their applications is discussed. The development of laser applications in medical therapy and diagnostics, material micro- and macro-processing as well as environmental monitoring and protection, safety, and security is presented.
