To supply a high flux of full adjustable polarization synchrotron radiation with low on-axis power density for users of HEPS, a new type of pure permanent magnetic (PPM) undulator structure called delta–knot has been proposed. The physical design of a prototype of a 3-period cryogenic delta–knot undulator is presented herein. It can achieve a maximum 1.6 T peak magnetic field with a periodic length of 40 mm using PrFeB material at 80 K. Specifications of the main magnetic structure as well as the field performances and radiation spectra at arbitrary polarization modes are also obtained. It is demonstrated that the on axis power density is significantly reduced in any polarization mode except the 45° incline polarization mode.

为了向HEPS用户提供低通量功率的全可调偏振同步加速器辐射的高通量，一种新型的纯永磁（PPM）起伏器结构被称为三角结。本文介绍了三周期低温三角结起伏器原型的物理设计。使用PrFeB材料在80 K时，它可以在周期长度为40 mm的情况下获得最大1.6 T峰值磁场。还获得了主要磁性结构的规格以及任意极化模式下的场性能和辐射光谱。已经证明，在除45°倾斜极化模式以外的任何极化模式下，轴上功率密度都会显着降低。