Hwang Ji-Gwang, Miyajima Tsukasa, Honda Yosuke, Kim Eun-San
Helmholtz-Zentrum Berlin (HZB), Albert-Einstein straße 15, 12489, Berlin, Germany.
KEK, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan.
Sci Rep. 2020 Nov 3;10(1):18905. doi: 10.1038/s41598-020-76054-w.
We demonstrate an experimental methodology for measuring the temporal distribution of pico-second level electron bunch with low energy using radial electric and azimuthal magnetic fields of an accelerating ([Formula: see text] mode) radio frequency (RF) cavity that is used for accelerating electron beams in a linear accelerator. In this new technique, an accelerating RF cavity provides a phase-dependent transverse kick to the electrons, resulting in the linear coupling of the trajectory angle with the longitudinal position inside the bunch. This method does not require additional devices on the beamline since it uses an existing accelerating cavity for the projection of the temporal distribution to the transverse direction. We present the theoretical basis of the proposed method and validate it experimentally in the compact-energy recovery linac accelerator at KEK. Measurements were demonstrated using a 2-cell superconducting booster cavity with a peak on-axis accelerating field ([Formula: see text]) of 7.21 MV/m.
我们展示了一种实验方法，用于利用加速（[公式：见正文]模式）射频（RF）腔的径向电场和方位磁场来测量低能皮秒级电子束团的时间分布，该射频腔用于在直线加速器中加速电子束。在这项新技术中，加速射频腔为电子提供与相位相关的横向踢动，从而导致束团内轨迹角与纵向位置的线性耦合。由于该方法利用现有的加速腔将时间分布投影到横向方向，因此不需要在束线上额外设置装置。我们给出了所提方法的理论基础，并在KEK的紧凑型能量回收直线加速器中通过实验对其进行了验证。使用一个2单元超导增强腔进行了测量，该腔的轴上峰值加速场（[公式：见正文]）为7.21 MV/m。
