# Precise Timing and Synchronization I

- Institution: CERN
- Department: CAS - CERN Accelerator School
- Speaker: Frank Ludwig
- Year: 2025
- Level: Graduate
- Language: English
- Source: [CERN](https://videos.cern.ch/record/3027071)
- Licence: [CERN](https://copyright.web.cern)
- Who can watch: Teens profiles and older (sources give no ratings; placed by Invisible Network from the source's own words)

This lecture examines synchronization systems in modern accelerators, focusing on radio-frequency (RF) methods and their role in achieving sub-10-fs beam arrival time precision. After motivating the need for high-precision timing, we analyze the short- and long-term stability of RF synchronization systems, including their fundamental limitations in ultra-low-jitter regimes. The discussion covers key microwave components—such as phase-locked loops (PLLs), mixers, oscillators, cables, amplifiers, and detectors—with emphasis on their phase-noise behavior, modeling techniques, and measurement techniques. We then explore global implementation strategies for synchronizing accelerator subsystems, highlighting approaches like un-stabilized chain systems, optical resynchronization, passive temperature stabilization, interferometer-based methods, and unidirectional transmission. Particular attention is given to subsystems critical for sub-10-fs jitter performance, including low-level RF (LLRF) systems and RF oscillator architectures, whose instabilities dominate timing errors in cutting-edge facilities.

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## Lectures

1. [Precise Timing and Synchronization I](https://invisiblenetwork.ai/learn/cern/3027071/6fc6405682f5), 43 min (CERN's player)