In this study,three specific scenarios of a novel accelerator light source mechanism called steady-state microbunching(SSMB)were studied:longitudinal weak focusing,longitudinal strong focusing,and generalized longitud...In this study,three specific scenarios of a novel accelerator light source mechanism called steady-state microbunching(SSMB)were studied:longitudinal weak focusing,longitudinal strong focusing,and generalized longitudinal strong focusing(GLSF).At present,GLSF is the most promising method for realizing high-power short-wavelength coherent radiation with mild requirements on modulation laser power.Its essence is to exploit the ultrasmall natural vertical emittance of an electron beam in a planar storage ring for efficient microbunching formation,like a partial transverse-longitudinal emittance exchange in the optical laser wavelength range.Based on an in-depth investigation of related beam physics,a solution for a GLSF SSMB storage ring that can deliver 1 kW average-power EUV light is presented.The work in this paper,such as the generalized Courant–Snyder formalism,analysis of theoretical minimum emittances,transverse-longitudinal coupling dynamics,and derivation of the bunching factor and modulation strengths for laser-induced microbunching schemes,is expected to be useful not only for the development of SSMB but also for future accelerator light sources in general that demand increasingly precise electron beam phase space manipulations.展开更多
Preserving beam quality during the transport of high-brightness electron bunches is crucial for advanced accelerator applications,such as particle colliders,free-electron lasers,and recirculating linacs.However,cohere...Preserving beam quality during the transport of high-brightness electron bunches is crucial for advanced accelerator applications,such as particle colliders,free-electron lasers,and recirculating linacs.However,coherent synchrotron radiation(CSR)significantly degrades beam quality when electron bunches pass through multi-bend isochronous beamlines,particularly for short bunches with non-ideal longitudinal profiles.Although several methods have been proposed to mitigate CSR effects,most rely on small-angle approximations or are limited to idealized bunch profiles.In this study,we present two improved methods for designing isochronous triple-bend achromat(TBA)beamlines that effectively mitigate CSR-induced emittance growth and longitudinal profile distortion without relying on small-angle approximations.The first method,an enhanced integral optimization approach,simplifies numerical optimization and can accurately handle larger deflection angles,making it suitable for practical applications that require flexible lattice configurations.The second method,an optimized I-matrix approach,completely cancels steady-state and transient CSR kicks through specific matrix constraints and higher-order dispersion optimization,enabling effective CSR suppression even with very large deflection angles.Systematic simulations demonstrate that both methods achieve excellent preservation of transverse emittance and longitudinal profiles.展开更多
Beam-tracking simulations have been extensively utilized in the study of collective beam instabilities in circular accelerators.Traditionally,many simulation codes have relied on central processing unit(CPU)-based met...Beam-tracking simulations have been extensively utilized in the study of collective beam instabilities in circular accelerators.Traditionally,many simulation codes have relied on central processing unit(CPU)-based methods,tracking on a single CPU core,or parallelizing the computation across multiple cores via the message passing interface(MPI).Although these approaches work well for single-bunch tracking,scaling them to multiple bunches significantly increases the computational load,which often necessitates the use of a dedicated multi-CPU cluster.To address this challenge,alternative methods leveraging General-Purpose computing on Graphics Processing Units(GPGPU)have been proposed,enabling tracking studies on a standalone desktop personal computer(PC).However,frequent CPU-GPU interactions,including data transfers and synchronization operations during tracking,can introduce communication overheads,potentially reducing the overall effectiveness of GPU-based computations.In this study,we propose a novel approach that eliminates this overhead by performing the entire tracking simulation process exclusively on the GPU,thereby enabling the simultaneous processing of all bunches and their macro-particles.Specifically,we introduce MBTRACK2-CUDA,a Compute Unified Device Architecture(CUDA)ported version of MBTRACK2,which facilitates efficient tracking of single-and multi-bunch collective effects by leveraging the full GPU-resident computation.展开更多
针对应用于硼中子俘获治疗的加速器中子源的束流偏转问题,为其低能束流传输线部分设计了一套斩束器,通过理论计算与软件模拟,验证方案的可行性。为了解决斩波器电场强度不均匀问题,引入圆弧电极设计结构,微波工作室(CST Studio Suite)...针对应用于硼中子俘获治疗的加速器中子源的束流偏转问题,为其低能束流传输线部分设计了一套斩束器,通过理论计算与软件模拟,验证方案的可行性。为了解决斩波器电场强度不均匀问题,引入圆弧电极设计结构,微波工作室(CST Studio Suite)模拟仿真表明其具有更好的电场分布均匀性。发展了基于Python程序的CST与TraceWin联合束流动力学模拟,结果表明设计的斩波器能够高效率地实现束流偏转功能,设计方案具有良好的实际应用价值和意义。展开更多
在质子治疗中,束流强度的精准控制是确保靶区剂量均匀性的关键。针对现有系统因开环控制、非线性漂移及噪声干扰导致的调节精度不足问题,本文提出一种基于每时钟指令数(Instruction Per Clock,IPC)与数字信号处理器(Digital Signal Proc...在质子治疗中,束流强度的精准控制是确保靶区剂量均匀性的关键。针对现有系统因开环控制、非线性漂移及噪声干扰导致的调节精度不足问题,本文提出一种基于每时钟指令数(Instruction Per Clock,IPC)与数字信号处理器(Digital Signal Processor,DSP)架构的束流调节电子单元(Beam Regulating Electronic Unit,BREU)。该单元通过加速器出口电离室实时采集束流反馈信号,结合DSP实现闭环控制,并创新性引入动态查找表(Look Up Table,LUT)技术,在每次照射前校准电弧电流与束流强度的非线性关系,消除长期漂移影响。实验结果表明,该束流调节电子单元性能稳定,且具备较高的调节精度。该系统通过自适应比例-积分-微分(Proportional Integral Derivative,PID)算法与噪声抑制的协同优化,显著提升了抗干扰能力与稳定性,为质子治疗设备的临床应用提供了高可靠性解决方案。展开更多
[Background]High harmonic cavities are widely used in electron storage rings to lengthen thebunch,lower the bunch peak current,thereby reducing the IBS effect,enhancing the Touschek lifetime,as well asproviding Landau...[Background]High harmonic cavities are widely used in electron storage rings to lengthen thebunch,lower the bunch peak current,thereby reducing the IBS effect,enhancing the Touschek lifetime,as well asproviding Landau damping,which is particularly important for storage rings operating with ultra-low emittance or atlow beam energy.[Purpose]To further increase the bunch length without additional hardware costs,the phasemodulation in a dual-RF system is considered.[Methods]In this paper,turn-by-turn simulations incorporating randomsynchrotron radiation excitation are conducted,and a brief analysis is presented to explain the bunch lengtheningmechanism.[Results]Simulation results reveal that the peak current can be further reduced,thereby mitigating IBSeffects and enhancing the Touschek lifetime.Although the energy spread increases,which tends to reduce thebrightness of higher-harmonic radiation from the undulator,the brightness of the fundamental harmonic can,in fact,beimproved.展开更多
基金supported by the National Key Research and Development Program of China(No.2022YFA1603401)National Natural Science Foundation of China(Nos.12035010 and 12342501)+1 种基金Beijing Outstanding Young Scientist Program(No.JWZQ20240101006)the Tsinghua University Dushi Program.
文摘In this study,three specific scenarios of a novel accelerator light source mechanism called steady-state microbunching(SSMB)were studied:longitudinal weak focusing,longitudinal strong focusing,and generalized longitudinal strong focusing(GLSF).At present,GLSF is the most promising method for realizing high-power short-wavelength coherent radiation with mild requirements on modulation laser power.Its essence is to exploit the ultrasmall natural vertical emittance of an electron beam in a planar storage ring for efficient microbunching formation,like a partial transverse-longitudinal emittance exchange in the optical laser wavelength range.Based on an in-depth investigation of related beam physics,a solution for a GLSF SSMB storage ring that can deliver 1 kW average-power EUV light is presented.The work in this paper,such as the generalized Courant–Snyder formalism,analysis of theoretical minimum emittances,transverse-longitudinal coupling dynamics,and derivation of the bunching factor and modulation strengths for laser-induced microbunching schemes,is expected to be useful not only for the development of SSMB but also for future accelerator light sources in general that demand increasingly precise electron beam phase space manipulations.
基金supported by the Natural Science Foundation of Shanghai(No.22ZR1470200)National Natural Science Foundation of China(Nos.12125508,12122514,12541503,12241501)Shanghai Pilot Program for Basic Research—Chinese Academy of Sciences,Shanghai Branch(JCYJ-SHFY-2021-010)。
文摘Preserving beam quality during the transport of high-brightness electron bunches is crucial for advanced accelerator applications,such as particle colliders,free-electron lasers,and recirculating linacs.However,coherent synchrotron radiation(CSR)significantly degrades beam quality when electron bunches pass through multi-bend isochronous beamlines,particularly for short bunches with non-ideal longitudinal profiles.Although several methods have been proposed to mitigate CSR effects,most rely on small-angle approximations or are limited to idealized bunch profiles.In this study,we present two improved methods for designing isochronous triple-bend achromat(TBA)beamlines that effectively mitigate CSR-induced emittance growth and longitudinal profile distortion without relying on small-angle approximations.The first method,an enhanced integral optimization approach,simplifies numerical optimization and can accurately handle larger deflection angles,making it suitable for practical applications that require flexible lattice configurations.The second method,an optimized I-matrix approach,completely cancels steady-state and transient CSR kicks through specific matrix constraints and higher-order dispersion optimization,enabling effective CSR suppression even with very large deflection angles.Systematic simulations demonstrate that both methods achieve excellent preservation of transverse emittance and longitudinal profiles.
基金supported by the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(MSIT)(No.RS-2022-00143178)the Ministry of Education(MOE)(Nos.2022R1A6A3A13053896 and 2022R1F1A1074616),Republic of Korea.
文摘Beam-tracking simulations have been extensively utilized in the study of collective beam instabilities in circular accelerators.Traditionally,many simulation codes have relied on central processing unit(CPU)-based methods,tracking on a single CPU core,or parallelizing the computation across multiple cores via the message passing interface(MPI).Although these approaches work well for single-bunch tracking,scaling them to multiple bunches significantly increases the computational load,which often necessitates the use of a dedicated multi-CPU cluster.To address this challenge,alternative methods leveraging General-Purpose computing on Graphics Processing Units(GPGPU)have been proposed,enabling tracking studies on a standalone desktop personal computer(PC).However,frequent CPU-GPU interactions,including data transfers and synchronization operations during tracking,can introduce communication overheads,potentially reducing the overall effectiveness of GPU-based computations.In this study,we propose a novel approach that eliminates this overhead by performing the entire tracking simulation process exclusively on the GPU,thereby enabling the simultaneous processing of all bunches and their macro-particles.Specifically,we introduce MBTRACK2-CUDA,a Compute Unified Device Architecture(CUDA)ported version of MBTRACK2,which facilitates efficient tracking of single-and multi-bunch collective effects by leveraging the full GPU-resident computation.
文摘针对应用于硼中子俘获治疗的加速器中子源的束流偏转问题,为其低能束流传输线部分设计了一套斩束器,通过理论计算与软件模拟,验证方案的可行性。为了解决斩波器电场强度不均匀问题,引入圆弧电极设计结构,微波工作室(CST Studio Suite)模拟仿真表明其具有更好的电场分布均匀性。发展了基于Python程序的CST与TraceWin联合束流动力学模拟,结果表明设计的斩波器能够高效率地实现束流偏转功能,设计方案具有良好的实际应用价值和意义。
文摘在质子治疗中,束流强度的精准控制是确保靶区剂量均匀性的关键。针对现有系统因开环控制、非线性漂移及噪声干扰导致的调节精度不足问题,本文提出一种基于每时钟指令数(Instruction Per Clock,IPC)与数字信号处理器(Digital Signal Processor,DSP)架构的束流调节电子单元(Beam Regulating Electronic Unit,BREU)。该单元通过加速器出口电离室实时采集束流反馈信号,结合DSP实现闭环控制,并创新性引入动态查找表(Look Up Table,LUT)技术,在每次照射前校准电弧电流与束流强度的非线性关系,消除长期漂移影响。实验结果表明,该束流调节电子单元性能稳定,且具备较高的调节精度。该系统通过自适应比例-积分-微分(Proportional Integral Derivative,PID)算法与噪声抑制的协同优化,显著提升了抗干扰能力与稳定性,为质子治疗设备的临床应用提供了高可靠性解决方案。
基金National Natural Science Foundation of China(12405168)The Fundamental Research Funds for the Central Universities,China(2024CDJXY004)。
文摘[Background]High harmonic cavities are widely used in electron storage rings to lengthen thebunch,lower the bunch peak current,thereby reducing the IBS effect,enhancing the Touschek lifetime,as well asproviding Landau damping,which is particularly important for storage rings operating with ultra-low emittance or atlow beam energy.[Purpose]To further increase the bunch length without additional hardware costs,the phasemodulation in a dual-RF system is considered.[Methods]In this paper,turn-by-turn simulations incorporating randomsynchrotron radiation excitation are conducted,and a brief analysis is presented to explain the bunch lengtheningmechanism.[Results]Simulation results reveal that the peak current can be further reduced,thereby mitigating IBSeffects and enhancing the Touschek lifetime.Although the energy spread increases,which tends to reduce thebrightness of higher-harmonic radiation from the undulator,the brightness of the fundamental harmonic can,in fact,beimproved.
