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Breakthrough in Electron Beam Technology at SLAC National Accelerator Laboratory
A group of physicists at the SLAC National Accelerator Laboratory in Menlo Park, California, has set a new record by producing electron beams characterized by the highest current and peak power to date. Their findings have been documented in a recently published paper in the esteemed journal Physical Review Letters.
For years, researchers have been innovating with high-energy laser light, applying it to fields ranging from nuclear physics to planetary science. In this latest study, the SLAC team focused on enhancing the performance of electron beams, endowing them with remarkable properties akin to those of advanced laser systems.
The central concept behind these powerful new electron beams is relatively straightforward: maximize the amount of electrical charge compressed into an extremely brief duration. In their experiments, the scientists successfully generated a staggering current of 100 kiloamps for just one quadrillionth of a second.
The experimental setup utilized a particle accelerator, where high-energy electron beams are propelled to accelerated speeds by powerful magnetic fields while traveling through a vacuum aided by radio waves. The researchers likened the motion of the electrons to that of a race car navigating an oval track—a situation where speed and trajectory are crucial. At speeds nearing 99% that of light, the electrons faced challenges when negotiating turns, prompting the need for an optimized approach to maintain their high velocity.
To achieve this, the research team strategically configured a millimeter-long string of electrons on the track. This arrangement allowed electrons at the front to traverse a less steep section of the radio wave, resulting in reduced energy post-turn—a phenomenon known as ‘chirping.’ To effectively control their path, magnets were employed to steer the electrons in a zigzag pattern before returning them to their original course.
Through this method, lower-energy electrons were forced to take a longer route, which inadvertently allowed higher-energy electrons to catch up, compressing the entire string of electrons. The researchers introduced an additional magnet that facilitated an energy-to-light conversion, thereby amplifying the chirping effect.
By repeatedly circulating these strings around the accelerator, they succeeded in further increasing the beam’s power while simultaneously shortening its duration. Ultimately, they achieved a pulse length of merely 0.3 micrometers, a noteworthy accomplishment in beam generation technology.
The implications of this groundbreaking work could extend into fields such as chemistry, where the research might pioneer new chemical processes or even contribute to the formation of innovative plasma states. Additionally, it holds promise for advancing our understanding of the properties of vacuum space.
More information: C. Emma et al, Experimental Generation of Extreme Electron Beams for Advanced Accelerator Applications, Physical Review Letters (2025). DOI: 10.1103/PhysRevLett.134.085001. On arXiv: DOI: 10.48550/arxiv.2411.10413
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phys.org