基于束流横向偏角与束流产生轴向磁场成正比的原理，设计了环状PCB结构的轴向B-dot探头，用于直接测量束流偏角。设计并搭建了标定平台对探头进行了测试，同时利用CST MWS程序对探头进行了建模计算。计算结果与实验结果一致，表明了轴向B-dot探头可直接应用于束流偏角测量。分析了影响探头频率适用范围的原因，并根据模拟计算结果给出了改进措施。该探测器在标定平台输入上升时间130 ns，半高宽160 ns的高压信号时，探头对偏角信号的响应灵敏度为314 mV/(kA·mrad)。

Beam monitors sensitive to the beam’s azimuthal B-dot field (sometimes referred as B-dots) are widely used to measure the displacement of beam centroid, as the beam generates a dipole term of the azimuthal magnetic field. Basing on the principle of the proportionality between the deflection angle and the difference of axial B field between the axially symmetrical positions, the axial B-dot probe has a potential use for beam deflection angle measurement. A calibration stand was built to test and improve the beam angle monitor, which was fabricated as a PCB structure. Meanwhile, simulations using the CST MWS codes were performed, demonstrating a good agreement with test results and giving some advices to suppress the disturbance of position deviation of the beam. Both the simulations and the experiments show that the axial B-dot monitor can be successfully used to measure the beam tilt directly.