Page History

...

• Giacomo is doing spatial, Ryan is spectral (roughly speaking)
  • both are interferometric, so the background we had in LCLS1 is mostly gone, but still have some background from stray light, for example
  • goose may be the effect of the remaining background, but not sure
• Formula that should work for both:  (S-B)/(S(goose)-B)
• B is the pedestal from dropped dark shots, computed with the IIR. NOTE:  denominator B is different than the numerator B, because it is the background at the time the goose data was taken.
• Giacomo will ensure that we run in a regime where (S(goose)-B) is not close to zero
• sxrx34917 (being analyzed by Giacomo and Stefan Droste).  this data is "zoomed out" in the time dimension, but will be more zoomed-in for LCLS-II.
• S(goose) comes from moving the laser out of the time window, and is done "offline" according to Giacomo every few hours
• algorithm should be same for spatial/spectral
• Questions for Giacomo:
  • the edge looks big in sxrx34917, do we definitely need to divide?
  • does the goose contain background from stray light, for example?