What kind of energy losses does the term "energy spread" include?

The energy spread for electron beams is due to the fluctuations of the synchrontron radiation (SR).

DIfferent elements contribute to the energy spread:

  • The SR in the arc section (unavoidable),
  • The SR in wiggler magnets,
  • The beamstrahlung at the IP due to the emission of SR in the strong EM field of the opposing beam.