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The "Target Time" doesn't work or energy jitter is higher than expected.
Check to make sure the "counter time" and "target time" match to within 0.1 ns when the "target time" is adjusted. When working correctly "Target Time" is repeatable and reliable, so you can go back to previous settings for "Target Time" and expect repeatable results. Caveat: certain underlying inputs into the RF locking system can change on the scale of once a year, so do not rely on target times and things you dig out of the archiver from months ago.
How do I know the Target Time is working? The "Target Time" and the "Counter Time" should match. If you change the "Target Time" and the "Counter Time" does not follow to within 0.1ns, then you should re-calibrate the femtosecond script.
To re-calibrate, please see When I change the target time the counter time changes, but by the wrong amount on the S20 Adjusting Laser Electron Beam Timing pageIncreased energy jitter is a symptom of the timing system not working correctly. Please see the troubleshooting section for the timing system in S20 for how to troubleshoot.
https://confluence.slac.stanford.edu/display/FACET/Adjusting+Laser-Electron+Beam+Timing
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