Page History

...

This was an option. However it restricts the vertical energy ROI. For soft xrays it would easily and frequently clip the image of the beam as well as require very careful ROI management, and so may have compromised random images for your data.

Another largely untested option are other running conditions recently found. This appears to delay tagging of all images by one event (3 fiducials). However, we are absolutely not certain this behavior is consistent and therefore don't recommend it for critical data.

Resolution

(From Tim Maxwell)

Time resolution is around 1.1 fs RMS for soft x-rays, 2.5 fs fwhm (in quadrature, of course). So actually pulse length is probably 4.3 - 9.7 fs FWHM.

This also doesn't include the "slippage resolution." That is, if they're using the full undulator, then by the end the x-rays can have slipped out of the electron slice by ~3 fs for soft x-rays. Obviously not a small number if trying to make 5 fs pulses. They've been advised to not use the full undulator when shorter pulses are more important than number of photons.