Junior Research Group Laser-Electron Acceleration
Extremely high accelerating fields exceeding hundreds GV/m can be generated during the interaction of ultra-intense laser pulses with transparent plasmas, stimulating innovative research fields spreading from the development of compact and lower-cost high-energy particle accelerators, advanced radiation sources to the TeV energy frontier accelerators. In HZDR, we explore the physics of high-intensity laser-plasma interactions aiming for better control on the injection and acceleration process at the same time improving the primary electron beam parameters, namely beam energy and energy spread, beam emittance and shot-to-shot stability. State-of-the-art ultrafast diagnostics are being developed to probe subtle details of the relativistic plasma and electron beam dynamics on micrometer-size at femtosecond-time scale. Furthermore potential applications of such electron beams particularly as drivers for secondary radiation sources are investigated. As our long term mission, improved understanding of the underlying interaction processes will advance the field forward moving from basic research on novel acceleration concepts towards user-readiness, from “acceleration to accelerators”.
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- Controlled injection at high peak current electron beam
Investigation of various injection methods aiming for generation of stable electron beam from the plasma acceleration mechanism is beeing persued. Particularly we explore a scheme to enhance the trapped charge within the quasimonoenergetic peak which can lead to ultra-high peak current electron beam (> 100 kA). Such high peak current will impact the next generation of radiation sources ranging from high-fields THz, high-brightness x-ray to gamma-ray sources, compact FELs and laboratory beam-driven laser-plasma accelerators.
Demonstration of a beam loaded nanocoulomb-class laser wakefield accelerator, J.P. Couperus, et.al. in Press Nature Communications (2017)
- Single-shot ultrafast probing of plasma waves and full phase-space beam characterization
We are developing techniques providing a few femtoseconds temporal and a few microns spatial resolution, to optically probe excited plasma waves. This extremely high spatio-temporal resolution is required since the structure of a plasma wave is typically only tens of microns and moving with a velocity close to the speed of light in vacuum. We aim to characterize the full phase-space distribution of a laser wakefield accelerated electron beam. Because the duration of such bunches is only a few femtoseconds, the most challenging task is to extract the longitudinal phase-space information. For this a powerful tool based on CTR detection in the frequency domain is being developed to measure the phase-space distribution with sub-femtosecond time resolution.
Development of a broadband optical spectrometer for measuring the pulse duration of ultrashort electron bunches, Omid Zarini, Diploma thesis Technische Universität Dresden (2013)
- Advanced radiation sources: Thomson backscattering, optical undulator, and betratron radiation
We have demonstrated the generation of ultrashort and tunable X-ray pulses by colliding the ELBE electron beam and the DRACO laser beam. By using laser wakefield accelerated electron beam this energy range can be easily extended to the γ-ray range. Ultrashort X-ray pulses can also be generated by relativistic electrons undergoing oscillatory motion during acceleration inside plasma waves. Our goal is the increase of the peak brightness of such X-ray beams which is required for future X-ray pump-probe spectroscopy experiments. This project is closely connected to The Helmholtz International Beamline for Extreme Fields (HIBEF) at the European XFEL in Hamburg.
High resolution energy-angle correlation measurement on hard X-rays from Laser-Thomson backscattering, A. Jochmann, A. Irman, et.al., Phys. Rev. Lett. 111, 114803 (2013)
Single-shot betatron source size measurement from a laser-wakefield accelerator, A. Köhler, et.al., Nucl. Instr. Meth. A 829, 265 (2016)
- Plasma target development and characterization
We develop a variety of plasma targets which later will be used as media for electron acceleration. These targets will provide a large range of plasma densities, i.e., from low plasma densities (provided by gas cells and pre-discharge plasma channels) to high plasma densities (provided by supersonic gas jets). Precise characterization of these targets is a key ingredient for the study of electron injection and acceleration mechanisms.
Tomographic characterisation of gas-jet targets for Laser Wakefield Acceleration, J.P. Couperus, et.al., Nucl. Instr. Meth. A 830, 504 (2016)