Since the beginning of the Large Hadron Collider (LHC) commissioning, spectral components at harmonics of the mains frequency (50 Hz) have been observed in the transverse beam spectrum. This paper presents an overview of the most important observations, collected during the latest physics operation of the LHC in 2018, which clearly indicates that the harmonics are the result of a real beam excitation rather than an instrumental feature. Based on these findings, potential sources of the perturbation are discussed and a correlation with power supply ripple originating from the magnets’ power supplies is presented.

中文翻译：

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大型强子对撞机横束光谱中50 Hz谐波的起源

自大型强子对撞机（LHC）调试开始以来，已在横向波束频谱中观察到了主电源频率（50 Hz）的谐波处的频谱分量。本文概述了LHC在2018年的最新物理操作期间收集的最重要的观察结果，这些观察结果清楚地表明谐波是真实光束激发的结果而不是仪器的特征。基于这些发现，讨论了潜在的扰动源，并提出了与源自磁体电源的电源纹波的相关性。