SLAC UED LLRF System Upgrade

TL;DR

This paper details the upgrade of SLAC's ultrafast electron diffraction system's laser timing and RF control using ATCA technology, significantly improving timing jitter and operational beam rate.

Contribution

The paper introduces a novel ATCA-based RF and laser timing synchronization system for UED, enhancing performance and maintainability.

Findings

Laser timing jitter reduced to 10 fs

Beam rate upgraded from 180 Hz to 360 Hz

System design and performance characterization provided

Abstract

The SLAC mega-electron-volt (MeV) ultrafast electron diffraction (UED) instrument is a powerful "electron camera" for the study of time-resolved, ultrafast atomic & molecular dynamics in chemical and solid-state systems. The UED laser timing synchronization is upgraded to SLAC (Advanced Telecommunications Computing Architecture) ATCA based femtosecond laser timing synchronization system. UED radio frequency (RF) gun cavity low level RF (LLRF) control is also being upgraded to SLAC ATCA based LLRF system to provide improved performance and maintainability. The new laser timing synchronization and LLRF control are implemented in one ATCA crate located in the laser room. A 2nd ATCA crate is set up to monitor the Klystron and sub-booster performance. With the ATCA based RF control system, the laser timing jitter has achieved 10 fs. The UED operation beam rate is being upgraded from 180 Hz to 360 Hz, which paves the way for a further upgrade of operation beam rate to 1 kHz in the future. In this paper, we present design details and characterization results of the implementation.