近日，日本量子科学技术研究所的Kai Huang及其研究团队取得一项新进展。经过不懈努力，他们成功获得激光尾流场加速千安培电子束的电光三维快照。相关研究成果已于2024年4月8日在国际知名学术期刊《光：科学与应用》上发表。

该研究团队成功捕捉到了等离子体外激光尾流场电子束的电光三维快照。研究人员结合了光学跃迁辐射成像与电光采样技术，精确地测量了电子束的三维形态。借助遗传算法，研究人员重建了电子束几微米级别的精细三维结构。

结果显示，电子束的横向尺寸小于30微米，电流剖面呈现出多峰结构。其中，主峰持续时间不足10飞秒，峰值电流超过1千安培。最大电子三维数密度达到了约9×10²¹m^-3。这一研究为在电子束输运线任意位置进行飞秒千安培电子束的三维密度监测提供了切实可行的方法。

据悉，激光尾场加速作为一种先进的加速器概念，以其超高的加速度梯度和产生高亮度电子束的能力而备受关注。三维密度作为粒子束质量的评价指标，与加速器的应用有着内在的联系。尽管该参数具有重要意义，但在激光尾流场加速度的研究中尚未进行实验测量。

附：英文原文

Title: Electro-optic 3D snapshot of a laser wakefield accelerated kilo-ampere electron bunch

Author: Huang, Kai, Jin, Zhan, Nakanii, Nobuhiko, Hosokai, Tomonao, Kando, Masaki

Issue&Volume: 2024-04-08

Abstract: Laser wakefield acceleration, as an advanced accelerator concept, has attracted great attentions for its ultrahigh acceleration gradient and the capability to produce high brightness electron bunches. The three-dimensional (3D) density serves as an evaluation metric for the particle bunch quality and is intrinsically related to the applications of an accelerator. Despite its significance, this parameter has not been experimentally measured in the investigation of laser wakefield acceleration. We report on an electro-optic 3D snapshot of a laser wakefield electron bunch at a position outside the plasma. The 3D shape of the electron bunch was detected by simultaneously performing optical transition radiation imaging and electro-optic sampling. Detailed 3D structures to a few micrometer levels were reconstructed using a genetic algorithm. The electron bunch possessed a transverse size of less than 30 micrometers. The current profile shows a multi-peak structure. The main peak had a duration of < 10fs and a peak current > 1kA. The maximum electron 3D number density was ~ 9×10²¹m ^-3. This research demonstrates a feasible way of 3D density monitoring on femtosecond kilo-ampere electron bunches, at any position of a beam transport line for relevant applications.

DOI: 10.1038/s41377-024-01440-2

Source: https://www.nature.com/articles/s41377-024-01440-2