Knowledge of the longitudinal beam parameters is important for understanding beam dynamics in any machine. In a linear accelerator (linac), to guarantee a stable motion in the longitudinal plane, the settings for the radio frequency cavities must be established by determining the phase and amplitude witnessed by the beam. In most modern hadron linacs, the requirements on phase and amplitude accuracy are 1° and 1% respectively, which is particularly challenging. Although systematic approaches for finding the phase and amplitude of cavities are available in many facilities with operational linacs, it is also vital to have a system in place when the standard time-of-flight based functionality is down or not yet available (as is often the case in the early stages of commissioning). Such a method should be relatively fast and simple, and should not depend on time-of-flight measurements or a rigorous phase calibration of the beam position monitors. This work presents a new phase- and amplitude-scan method which only requires information from transverse positions measured at beam position monitors downstream of the cavity being scanned. The scanning then relies on transverse trajectory correction, which has been developed extensively by the community. As a by-product, this method can also provide estimates for a cavity’s transverse misalignment. The method has been developed and tested for a single-cell cavity; the simulated effectiveness for a multicell cavity is also presented.

中文翻译：

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基于位置的腔调整

纵向梁参数的知识对于理解任何机器中的梁动力学很重要。在线性加速器（直线加速器）中，为了确保在纵向平面中稳定运动，必须通过确定光束所见证的相位和幅度来建立射频腔的设置。在大多数现代强子直线加速器中，对相位和幅度精度的要求分别为1°和1％，这尤其具有挑战性。尽管在许多具有直线加速器的设施中都可以找到用于确定腔的相位和振幅的系统方法，但是在基于标准飞行时间的功能失效或尚不可用时（通常是在调试的早期阶段）。这样的方法应该相对快速简单。并且不应依赖于飞行时间测量或光束位置监控器的严格相位校准。这项工作提出了一种新的相位和幅度扫描方法，该方法仅需要来自在被扫描空腔下游的光束位置监视器处测量到的横向位置的信息。然后，扫描依靠横向轨迹校正，该轨迹已被社区广泛开发。作为副产品，该方法还可以提供腔体横向未对准的估计值。该方法已经针对单细胞腔进行了开发和测试；还介绍了多腔空腔的模拟有效性。这项工作提出了一种新的相位和幅度扫描方法，该方法仅需要来自在被扫描空腔下游的光束位置监视器处测量到的横向位置的信息。然后，扫描依靠横向轨迹校正，该轨迹已被社区广泛开发。作为副产品，该方法还可以提供腔体横向未对准的估计值。该方法已经针对单细胞腔进行了开发和测试；还介绍了多腔空腔的模拟有效性。这项工作提出了一种新的相位和幅度扫描方法，该方法仅需要来自在被扫描空腔下游的光束位置监视器处测量到的横向位置的信息。然后，扫描依靠横向轨迹校正，该轨迹已被社区广泛开发。作为副产品，该方法还可以提供腔体横向未对准的估计值。该方法已经针对单细胞腔进行了开发和测试；还介绍了多腔空腔的模拟有效性。该方法已经针对单细胞腔进行了开发和测试；还介绍了多腔空腔的模拟有效性。该方法已经针对单细胞腔进行了开发和测试；还介绍了多腔空腔的模拟有效性。