Feed-forward control of the amplitude and the phase of a high-power RF pulse based on the overdrive technique
Feed-forward control of the amplitude and the phase of a high-power RF pulse based on the overdrive technique
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基于过驱动技术的高功率射频脉冲幅度和相位的前馈控制
DOI：
10.1016/j.nima.2012.03.004
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Shigeru Kashiwagi
中科院分区：
文献类型：
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作者：
A.Adare;H.Hamagaki;他(PHENIX Collaboration);神本丈;Kazuyuki Sakaue;Koichi Hamaguchi;T. Ohsawa;Shigeru Kashiwagi
为了精确控制电子直线加速器中脉冲射频功率的幅值和相位，使加速场恒定，我们研制了一种新型的前馈控制系统。通过将抗变化控制信号施加到低电平系统中的可变衰减器和移相器，来补偿持续时间为几微秒的RF脉冲中的幅度和相位的快速变化和纹波。该系统利用了模拟电路中常用的数字信号处理技术来加快模拟移相器的慢响应，同时对控制信号进行数字处理，因此，该方法是模拟和数字技术的混合。在大坂大学L波段电子直线加速器的7.6 μ s长射频脉冲中，通过这些方法，幅度和相位的峰-峰变化分别从11.6%和6.1°减小到0.4%和0.3°。
We have developed a new feed-forward control system to precisely control the amplitude and phase of the pulsed RF power in an electron linear accelerator (linac) to make the accelerating field constant. Fast variations and ripples in the amplitude and the phase in RF pulses of some-microsecond duration are compensated for by applying anti-variation control signals to a variable attenuator and a phase shifter in the low-level system. The system makes use of the overdrive technique, which is commonly used in analog circuits, to speed up the slow response of the analog phase shifter, while the control signals are digitally processed; thus, the method is a hybrid of analog and digital techniques. Peak-to-peak variations in the amplitude and phase are reduced by these means from 11.6% to 0.4% and from 6.1° to 0.3°, respectively, in 7.6-μs-long RF pulses for the L-band electron linac at Osaka University.