Online monitoring of beam phase and intensity using lock-in amplifiers
Online monitoring of beam phase and intensity using lock-in amplifiers
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DOI：
10.1016/j.nima.2013.08.056
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发表时间：
2013-11
影响因子：
1.4
通讯作者：
R. Koyama;N. Sakamoto;M. Fujimaki;N. Fukunishi;A. Goto;M. Hemmi;M. Kase;K. Suda;Tamaki Watanabe-Tamaki
中科院分区：
文献类型：
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作者：
R. Koyama;N. Sakamoto;M. Fujimaki;N. Fukunishi;A. Goto;M. Hemmi;M. Kase;K. Suda;Tamaki Watanabe-Tamaki
我们已经开发了一个专门用于重离子回旋加速器的监测系统，其中包括锁定放大器(LIA)，它可以测量来自相位探测器的信号的束相，幅度为几百纳伏。我们比较了LIA系统和采用示波器(OSC)的传统系统的性能。通过在较宽的束流动态范围内的测量，证实了LIA系统比OSC系统具有更高的精度。用这两个系统对一个低速增益(1.5)的环形回旋加速器进行了等时测量，它们之间有很好的一致性。然而，在速度增益为4.0的环形回旋加速器的情况下，使用OSC系统和LIA系统测量的束流相位存在差异。结果表明，这是由于循环束团的相位宽度随加速电压的径向分布有很大的径向变化。同时也证实了光缆色散对OSC系统测量光束相位的干扰。
We have developed a monitoring system dedicated for heavy-ion cyclotrons that incorporates lock-in amplifiers (LIAs) that can measure the beam phase of signals from phase probe with an amplitude of a few hundred nanovolts. We have compared the performance of the LIA system with that of a conventional system that incorporates oscilloscopes (OSCs). It was confirmed that the LIA system has a much higher precision than the OSC system by the measurement with a wide dynamic range of beam current. Isochronism measurements for a ring cyclotron with a low velocity gain (1.5) were made using both systems and excellent agreement was found between them. However there was a discrepancy between the beam phase measurements using the OSC system and the LIA system, for the case of a ring cyclotron with a high velocity gain of 4.0. It turned out due to a large radial variation of the phase width of circulating beam bunch according to a radial distribution of the acceleration voltage. It was also confirmed that the cable dispersion disturbs the beam-phase measurement using OSC system.