Manipulation electron beam phase space technology by laser-electron interaction has been widely used in accelerator-based light sources. The energy of the electron beam can be modulated effectively under resonant conditions by using an intense external laser beam incident into the undulator together with the electron beam. Enhancing the modulation efficiency is crucial for the performance of high repetition rate seeded free electron lasers (FELs) and other related devices. In this paper, we propose a new scheme to augment the efficiency of laser-electron interaction by employing the interaction between a vortex beam and an electron beam within a helical undulator. Three-dimensional time-dependent simulation results indicate that the modulation repetition rate of laser-electron interaction using a vortex beam can be improved by one order of magnitude over the conventional Gaussian beam at the same input power.

Recent advancements in electron beam compression methods have enabled the production of ultrashort electron beams at the sub-femtosecond scale, significantly expanding their applications. However, the temporal resolution of these beams is primarily limited by the flight time jitter, especially during their generation in photocathode RF electron guns. In this paper, to mitigate the impact of microwave phase jitter on the flight time jitter inside the electron gun, we designed a 2.3-cell X-band electron gun, which enables the electron beams to acquire maximum output energy and minimum in-gun flight time at the same injection phase. Moreover, the tolerance of the cavity's machining errors is assessed and the RF input coupler of this cavity has been designed. Our simulation results indicate that this design provides a solid foundation for further improving the temporal resolution of the electron beam.

The utilization of laser modulation techniques shows potential in producing sub-femtosecond electron beams within photoinjector electron guns. The precise spatial alignment between the modulated laser and electron beam is crucial for the stable emission of sub-femtosecond electron beams. In practical applications, inevitable lateral positional fluctuations are present in both the modulated laser and electron beam pulses, resulting in uneven and suboptimal modulation effects of the laser on the electron beam. Photocathode electron guns commonly utilize solenoid focusing for transverse electron beam concentration, inducing transverse phase space coupling and causing the laser-induced transverse jitter in the electron gun to not accurately reflect the transverse jitter of the electron beam. This study seeks to employ coherent lasers and devise a solenoid coil to disentangle the transverse phase space of the electron beam, ensuring that the transverse jitter of the electron beam aligns with the jitter of the modulated laser at the focal point.

Manipulation electron beam phase space technology by laser-electron interaction has been widely used in accelerator-based light sources. The energy of the electron beam can be modulated effectively under resonant conditions by using an intense external laser beam incident into the undulator together with the electron beam. Enhancing the modulation efficiency is crucial for the performance of high repetition rate seeded free electron lasers (FELs) and other related devices. In this paper, we propose a new scheme to augment the efficiency of laser-electron interaction by employing the interaction between a vortex beam and an electron beam within a helical undulator. Three-dimensional time-dependent simulation results indicate that the modulation repetition rate of laser-electron interaction using a vortex beam can be improved by one order of magnitude over the conventional Gaussian beam at the same input power.

The utilization of laser modulation techniques shows potential in producing sub-femtosecond electron beams within photoinjector electron guns. The precise spatial alignment between the modulated laser and electron beam is crucial for the stable emission of sub-femtosecond electron beams. In practical applications, inevitable lateral positional fluctuations are present in both the modulated laser and electron beam pulses, resulting in uneven and suboptimal modulation effects of the laser on the electron beam. Photocathode electron guns commonly utilize solenoid focusing for transverse electron beam concentration, inducing transverse phase space coupling and causing the laser-induced transverse jitter in the electron gun to not accurately reflect the transverse jitter of the electron beam. This study seeks to employ coherent lasers and devise a solenoid coil to disentangle the transverse phase space of the electron beam, ensuring that the transverse jitter of the electron beam aligns with the jitter of the modulated laser at the focal point.

Recent advancements in electron beam compression methods have enabled the production of ultrashort electron beams at the sub-femtosecond scale, significantly expanding their applications. However, the temporal resolution of these beams is primarily limited by the flight time jitter, especially during their generation in photocathode RF electron guns. In this paper, to mitigate the impact of microwave phase jitter on the flight time jitter inside the electron gun, we designed a 2.3-cell X-band electron gun, which enables the electron beams to acquire maximum output energy and minimum in-gun flight time at the same injection phase. Moreover, the tolerance of the cavity's machining errors is assessed and the RF input coupler of this cavity has been designed. Our simulation results indicate that this design provides a solid foundation for further improving the temporal resolution of the electron beam.