Measuring the topological charge (TC) of optical vortex beams by the edge-diffraction pattern of a single plate is proposed and demonstrated. The diffraction fringes can keep well discernible in a wide three-dimensional range in this method. The redundant fringes of the diffracted fork-shaped pattern in the near-field can determine the TC value, and the orientation of the fork tells the handedness of the vortex. The plate can be opaque or translucent, and the requirement of the translucent plate for TC measurement is analyzed. Measurement of TCs up to ±40 is experimentally demonstrated by subtracting the upper and lower fringe numbers with respect to the center of the light. The plate is easy to get, and this feasible measurement can bring great convenience and efficiency for researchers.

介绍了一种新型传感器Turbo-ICT在BEPCII输运线电荷量测量上的应用。 该探测器的电荷测量系统具有强抗干扰能力和较高的信噪比，能满足各种运行模式，尤其是Top-Up模式时的测量需求。介绍了该系统的工作原理、设计思想和功能。目前，该系统已在BEPCII电子输运线上在线应用于电荷量测量和注入效率的计算，文中给出了实际测量结果以及该系统进一步优化的方案。