A signal transmission line and its characteristics were analyzed in detail for a beam-current monitor (CM) for long-pulsed electron beams. The monitor was based on a conventional current transformer, which comprised an induction coil wound around a ferrite core. The signal transmission and noise generation mechanism were analyzed by theoretical models based on balanced and unbalanced coaxial transmission circuits to effectively reduce noises superimposed on the beam-current signal waveform. The results of numerical analyses based on the theoretical models were in good agreement with those of an experiment for verification. It was found that the noise signals were generated by a high-power klystron operation and they were mode-transformed on the way to the transmission line. These results show that the locations of the grounded points in the transmission line were important. Based on a symmetrically configured three-line circuit theory, a new highly symmetrically configured coaxial transmission line is proposed to effectively suppress noises generated in CM. This report describes in detail the numerical and experimental analysis of a signal transmission line with coaxial cables for CM where the noise generation mechanism and its reduction technique are deeply involved.

中文翻译：

---

直线加速器束流监测器平衡与非平衡信号传输线分析及降噪技术

详细分析了用于长脉冲电子束的束电流监测器 (CM) 的信号传输线及其特性。该监视器基于传统的电流互感器，它包括一个缠绕在铁氧体磁芯上的感应线圈。通过基于平衡和非平衡同轴传输电路的理论模型分析信号传输和噪声产生机制，有效降低叠加在束流信号波形上的噪声。基于理论模型的数值分析结果与验证实验的结果吻合良好。发现噪声信号是由大功率速调管操作产生的，它们在通往传输线的途中进行了模式转换。这些结果表明，传输线中接地点的位置很重要。基于对称配置的三线电路理论，提出了一种新的高度对称配置的同轴传输线，以有效抑制CM中产生的噪声。本报告详细描述了用于 CM 的同轴电缆信号传输线的数值和实验分析，其中深度涉及噪声产生机制及其降低技术。