中文摘要：

本文介绍了HT-7诊断中性束装置束评价系统的基本结构和工作原理；分析靶板采样孔的遮挡效应、束腰位置和前、后靶上采样铜柱的温升比值的关系，解释了相同参数下后靶板温升较高的实验现象；根据前、后靶板的平均温升比值，计算了装置运行中的柬流焦距，结果显示其误差不大于5％。

英文摘要：

The structure and principle of Diagnostic Neutral Beam in HT-7 tokamak is introduced. The factors affecting the ratio of temperature rise, shutoff effect of sample hole and beam focus are analyzed, and experiment results could be explained by analysis. According to ratio of average of temperature rise, the focus of beam was calculated. The result revealed that error was no larger than 0.05, which is required by the system design.