A novel approach to accelerating ultracold electron bunches, while still preserving their brightness.
A novel approach to accelerating ultracold electron bunches, while still preserving their brightness. lead image
Ultracold electron bunches hold potential for applications ranging from protein crystallography to the production of high-intensity X-rays. Accelerating bunches to the required energy levels is very challenging but has been achieved through enhancements to the Ultra Cold Electron Source (UCES) beamline.
UCES approaches alone, however, have a practical limit for the maximum attainable bunch energy. Using the UCES and an additional radio frequency (RF) accelerator, Nijhof et al. successfully accelerated ultracold electron bunches to 35 keV. The work marks significant movement toward single-shot protein crystallography in a tabletop setup, and acceleration to relativistic speeds for creating high-intensity X-rays.
The UCES creates bunches initially extracted with a static electric field, requiring additional measures for further acceleration.
“RF acceleration of electron bunches is employed by all modern particle accelerator institutes in one way or another,” said author Daniel Nijhof. “This is the first time for electron bunches created from a laser-cooled and trapped gas to be accelerated in this fashion.”
The UCES produces electrons from a laser-cooled and trapped atomic gas that allows electron bunches to be created from relatively large areas, mimicking conventional photocathode sources.
“Not only were the bunches successfully accelerated, but their quality also was maintained, as established by means of a diffraction sample inserted into their path,” Nijhof said.
Accelerating the bunches to a higher kinetic energy required a complex interplay of subsystems. Utilizing a compact RF accelerator structure brings Nijhof et al. one step closer to realizing accessible single-shot protein crystallography and creating high-intensity X-rays.
Source: “RF acceleration of ultracold electron bunches,” by Daniel Ferdinand Jan Nijhof, Tim Christiaan Hendrik de Raadt, Julius Valentijn Huijts, Jim Gerardus Hubertus Franssen, P.H.A. Mutsaers, and O.J. Luiten, Journal of Structural Dynamics (2023). The article can be accessed at https://doi.org/10.1063/4.0000200 .
This paper is part of the Enabling Methods in Ultrafast Electron Diffraction, Scattering and Imaging Collection, learn more here .
