Using the conventional coil manufacturing method, the iron core of a small aperture quadrupole magnet needs to be divided into four or more segments to install the excitation coils, which brings assembly errors and generates high-order magnetic field harmonics. In this paper, the development of a high-precision small-aperture quadrupole magnet named HQ22 using copper plate coils is described. The magnet has a bore aperture of 22 mm, a gradient of 90 T/m, and an effective length of 0.36 m. Its coil is mainly composed of a number of U-shaped copper plates, electrical connection sheets, and insulating sheets, which are directly assembled and connected on the pole. Outside the coil, water box with cooling water channel inside is installed to provide indirect cooling to the coil. Using copper plate coil, one-piece or two-piece structure can be adopted for the iron core, so the assembly error is reduced and magnetic field quality can be improved. The research provides an attractive technical scheme for small aperture quadrupole magnets in future light sources. The detailed magnet design, magnetic field calculation and measurement results of HQ22 are presented, and the application prospect of copper plate coil is discussed.

使用传统的线圈制造方法，小孔径四极磁铁的铁芯需要分成四段或更多段来安装励磁线圈，这会带来装配误差并产生高次磁场谐波。在本文中，描述了使用铜板线圈开发名为 HQ22 的高精度小孔径四极磁铁。磁体的孔径为22 mm，梯度为90 T/m，有效长度为0.36 m。其线圈主要由若干U形铜板、电气连接片、绝缘片组成，直接组装连接在极柱上。盘管外安装带冷却水道的水箱，对盘管进行间接冷却。使用铜板线圈，铁芯可采用一件式或两件式结构，减少装配误差，提高磁场质量。该研究为未来光源中的小孔径四极磁铁提供了有吸引力的技术方案。介绍了HQ22的详细磁体设计、磁场计算和测量结果，并讨论了铜板线圈的应用前景。