Ionization chambers are widely used for dosimetry with megavoltage photon beams. Several properties of ionization chambers, including the cable effect, polarity effect, and ion recombination loss, are described in standard dosimetry protocols. The cable effect is categorized as the leakage current and Compton current, and careful consideration of these factors has been described not only in reference dosimetry but also in large fields. However, the mechanism of Compton current in the cable has not been investigated thoroughly. The cable effect of ionization chambers in 6 MV X‐ray beam was evaluated by measurement, and the mechanism of Compton current was investigated by Monte Carlo simulation.

中文翻译：

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通过测量和蒙特卡洛模拟估算兆伏光子束中的电缆效应。

电离室被广泛用于兆电压光子束的剂量测定。标准剂量协议中描述了电离室的几种特性，包括电缆效应，极性效应和离子重组损失。电缆效应可分为泄漏电流和康普顿电流，不仅在参考剂量法中，而且在大领域中，都已经仔细考虑了这些因素。但是，电缆中的康普顿电流机制尚未得到彻底研究。通过测量评估了6 MV X射线束中电离室的电缆效应，并通过蒙特卡洛模拟研究了康普顿电流的机理。