对偏心束流在束流管道中产生的电磁场和束流模拟装置的偏心同轴线中的电磁场进行了理论分析。分析表明,在束流模拟装置阻抗较小时,二者存在显著差异。该差异对束流流强探测器、束流位置探测器和束流偏角探测器的标定有一定的影响。如果采用阻抗为50 Ω的束流模拟装置标定束流位置探测器,得到的等效管道半径将比真实值偏小19%。利用理论分析结果,合理地解释了一个B-dot束流位置探测器的标定结果。

The coaxial beam test stand was used to calibrate the beam position monitors and the beam current monitors. The electric and magnetic field in the beam test stand with displaced inner conductor was analyzed in theory. The results show that, when the impedance of the test stand is not very small, the electromagnetic (EM) field in the test stand is significantly different to the EM field in the beam-pipe generated by the beam. The difference of the EM field can lead to non-negligible calibration errors of beam monitors such as B-dot monitors and resistive wall monitors. The influence on the B-dot beam position monitors predicted by the theory calculation agrees well with experimental results.