The article presents the investigation results on the main angular divergence sources of a high-current relativistic electron beam when it passes through a real 12° bend magnet of the transport system in the linear induction accelerator (LIA), being developed by collaboration of Budker Institute of Nuclear Physics (BINP), Novosibirsk, Russia, and Russian Federal Nuclear Center—Zababakhin All-Russia Research Institute of Technical Physics (RFNC-VNIITF). The main results of the work are the calculated trajectories of the beam electrons, the shape of its cross section, as well as the change in the normalized emittance of the beam as it passes through the region of the bend magnet. It was shown that at typical beam parameters—electron energy of 20 MeV, beam current of 2 kA, and beam radius of 2 cm—the emittance of a high-current relativistic electron beam with uniform current and charge densities after the bend element is determined mostly by the magnet aberrations and much less by the beam self-fields. Optimization of the dipole magnet geometry made it possible to achieve a substantial decrease in the beam emittance with geometric expansion of the magnet in the median plane of the beam.

中文翻译：

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弯曲磁体中高电流相对论电子束的发射率变化


本文介绍了与巴德克研究所合作开发的直线感应加速器（LIA）中强流相对论电子束通过传输系统真实12°弯曲磁体时的主要角发散源的研究结果俄罗斯新西伯利亚核物理研究所 (BINP) 和俄罗斯联邦核中心 - 扎巴巴欣全俄技术物理研究所 (RFNC-VNIITF)。这项工作的主要结果是计算出束流电子的轨迹、其横截面的形状，以及束流通过弯曲磁体区域时归一化发射率的变化。结果表明，在典型的束流参数（电子能量为20 MeV、束流为2 kA、束流半径为2 cm）下，确定了弯曲单元后具有均匀电流和电荷密度的高电流相对论电子束的发射率主要是由磁体像差引起的，而较少是由束自场引起的。偶极磁体几何形状的优化使得可以通过磁体在束中平面中的几何扩展来实现束发射率的大幅降低。