X-ray sources with tunable energy spectra have a wide range of applications in different scenarios due to their different penetration depths.However,existing x-ray sources face difficulties in terms of energy regulati...X-ray sources with tunable energy spectra have a wide range of applications in different scenarios due to their different penetration depths.However,existing x-ray sources face difficulties in terms of energy regulation.In this paper,we present a scheme for tuning the energy spectrum of a betatron x-ray generated from a relativistic electron bunch oscillating in a plasma wakefield.The center energy of the x-ray source can be tuned from several keV to several hundred keV by changing the plasma density,thereby extending the control range by an order of magnitude.At different central energies,the brightness of the betatron radiation is in the range of 3.7×10^(22)to 5.5×10^(22)photons/(0.1%BW·s·mm^(2)·mrad^(2))and the photon divergence angle is about 2 mrad.This high-brightness,energy-controlled betatron source could pave the way to a wide range of applications requiring photons of specific energy,such as phase-contrast imaging in medicine,non-destructive testing and material analysis in industry,and imaging in nuclear physics.展开更多
The integrated gradient of a quadrupole will be deviated by a close neighboring sextupole, and this is called the effect of fringe field interference. Using the Lie algebra techniques, an analytical expression for the...The integrated gradient of a quadrupole will be deviated by a close neighboring sextupole, and this is called the effect of fringe field interference. Using the Lie algebra techniques, an analytical expression for the betatron tune shift due to this effect has been derived. The process does not depend on the supposition of the thin-lens quadrupoles. It can be used to estimate the tune shift differences between the designed lattice and the one including the fringe field interference. More generally, the method can be applied to other kinds of fringe field interference.展开更多
The betatron radiation source features a micrometer-scale source size,a femtosecond-scale pulse duration,milliradianlevel divergence angles and a broad spectrum exceeding tens of keV.It is conducive to the high-contra...The betatron radiation source features a micrometer-scale source size,a femtosecond-scale pulse duration,milliradianlevel divergence angles and a broad spectrum exceeding tens of keV.It is conducive to the high-contrast imaging of minute structures and for investigating interdisciplinary ultrafast processes.In this study,we present a betatron X-ray source derived from a high-charge,high-energy electron beam through a laser wakefield accelerator driven by the 1 PW/0.1 Hz laser system at the Shanghai Superintense Ultrafast Laser Facility(SULF).The critical energy of the betatron X-ray source is 22±5 keV.The maximum X-ray flux reaches up to 4×10^(9)photons for each shot in the spectral range of 5-30 keV.Correspondingly,the experiment demonstrates a peak brightness of 1.0×10^(23)photons·s^(-1)·mm^(-2)·mrad^(-2)·0.1%BW^(-1),comparable to those demonstrated by third-generation synchrotron light sources.In addition,the imaging capability of the betatron X-ray source is validated.This study lays the foundation for future imaging applications.展开更多
根据小型电子感应加速器的工作特点,设计了由灯丝占空比调节电路和注入电流反馈电路组成的灯丝电源。通过数字信号处理器(Digital Signal Processor,DSP)输出两路脉冲宽度调制(Pulse-Width Modulation,PWM)信号驱动半桥电路,半桥电路输...根据小型电子感应加速器的工作特点,设计了由灯丝占空比调节电路和注入电流反馈电路组成的灯丝电源。通过数字信号处理器(Digital Signal Processor,DSP)输出两路脉冲宽度调制(Pulse-Width Modulation,PWM)信号驱动半桥电路,半桥电路输出正负交替电压脉冲至隔离变压器初级,变压器次级电压加载在灯丝上,供灯丝加热。通过收集加速管管壁电流和靶电流作为注入电流反馈信号,DSP根据反馈信号调节灯丝电压脉冲占空比,实现灯丝发射电流的调整,使灯丝注入到加速管内的电流处在最佳值。实验测试结果表明:灯丝电源可以使加速器输出剂量率保持在最佳状态,输出剂量率稳定度优于11.3%/10 min,灯丝电源满足小型电子感应加速器的需求。展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11921006 and 12175058)the Beijing Distinguished Young Scientist Program and National Grand Instrument Project (Grant No.SQ2019YFF01014400)+1 种基金the Beijing Municipal Science&Technology Commission,Administrative Commission of Zhongguancun Science Park (Grant No.Z231100006023003)in part funded by United Kingdom EPSRC (Grant Nos.EP/G054950/1,EP/G056803/1,EP/G055165/1,and EP/M022463/1)。
文摘X-ray sources with tunable energy spectra have a wide range of applications in different scenarios due to their different penetration depths.However,existing x-ray sources face difficulties in terms of energy regulation.In this paper,we present a scheme for tuning the energy spectrum of a betatron x-ray generated from a relativistic electron bunch oscillating in a plasma wakefield.The center energy of the x-ray source can be tuned from several keV to several hundred keV by changing the plasma density,thereby extending the control range by an order of magnitude.At different central energies,the brightness of the betatron radiation is in the range of 3.7×10^(22)to 5.5×10^(22)photons/(0.1%BW·s·mm^(2)·mrad^(2))and the photon divergence angle is about 2 mrad.This high-brightness,energy-controlled betatron source could pave the way to a wide range of applications requiring photons of specific energy,such as phase-contrast imaging in medicine,non-destructive testing and material analysis in industry,and imaging in nuclear physics.
基金support and assistance. This work was supported by National Natural Science Foundation of China (No. 11105165)
文摘The integrated gradient of a quadrupole will be deviated by a close neighboring sextupole, and this is called the effect of fringe field interference. Using the Lie algebra techniques, an analytical expression for the betatron tune shift due to this effect has been derived. The process does not depend on the supposition of the thin-lens quadrupoles. It can be used to estimate the tune shift differences between the designed lattice and the one including the fringe field interference. More generally, the method can be applied to other kinds of fringe field interference.
基金supported by the National Natural Science Foundation of China(Grant Nos.12388102,12225411,12105353 and 12174410)the CAS Project for Young Scientists in Basic Research(Grant No.YSBR060)+3 种基金the Program of Shanghai Academic Research Leader(Grant No.22XD1424200)the State Key Laboratory Program of the Chinese Ministry of Science and Technologythe CAS Youth Innovation Promotion Association(Grant No.2022242)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB0890201 and XDB0890202)。
文摘The betatron radiation source features a micrometer-scale source size,a femtosecond-scale pulse duration,milliradianlevel divergence angles and a broad spectrum exceeding tens of keV.It is conducive to the high-contrast imaging of minute structures and for investigating interdisciplinary ultrafast processes.In this study,we present a betatron X-ray source derived from a high-charge,high-energy electron beam through a laser wakefield accelerator driven by the 1 PW/0.1 Hz laser system at the Shanghai Superintense Ultrafast Laser Facility(SULF).The critical energy of the betatron X-ray source is 22±5 keV.The maximum X-ray flux reaches up to 4×10^(9)photons for each shot in the spectral range of 5-30 keV.Correspondingly,the experiment demonstrates a peak brightness of 1.0×10^(23)photons·s^(-1)·mm^(-2)·mrad^(-2)·0.1%BW^(-1),comparable to those demonstrated by third-generation synchrotron light sources.In addition,the imaging capability of the betatron X-ray source is validated.This study lays the foundation for future imaging applications.
文摘根据小型电子感应加速器的工作特点,设计了由灯丝占空比调节电路和注入电流反馈电路组成的灯丝电源。通过数字信号处理器(Digital Signal Processor,DSP)输出两路脉冲宽度调制(Pulse-Width Modulation,PWM)信号驱动半桥电路,半桥电路输出正负交替电压脉冲至隔离变压器初级,变压器次级电压加载在灯丝上,供灯丝加热。通过收集加速管管壁电流和靶电流作为注入电流反馈信号,DSP根据反馈信号调节灯丝电压脉冲占空比,实现灯丝发射电流的调整,使灯丝注入到加速管内的电流处在最佳值。实验测试结果表明:灯丝电源可以使加速器输出剂量率保持在最佳状态,输出剂量率稳定度优于11.3%/10 min,灯丝电源满足小型电子感应加速器的需求。
