touschekLifetime

• description: touschekLifetime computes Touschek lifetime using A. Piwinski's formula [23,24].

• examples:
  touschekLifetime aps.life -twiss=aps.twi -aper=aps.aper -part=2e10 -coupling=0.01 -length=6

• synopsis:
  touschekLifetime outputFile -twiss=<twissFile> -aperture=<momentumApertureFile> -charge=<nC>|-particles=<value> -coupling=<value> -RF=Voltage=<MV>,harmonic=<value>|-length=<mm> [-emitxInput=<value>] [-deltaInput=<value>] [-verbosity=<value>]

• files: outputFile -- Contains resulting Touschek lifetime.

• switches:
  • -twiss -- A twiss parameter file from elegant. You must use the radiation_integrals flag in twiss_output.
  • -aperture -- A momentum aperture file from elegant. This file can contain a subset of elements of twissFile (for example: only Quadrupole elements). However, the Twiss and momentum aperture files must cover the same beamline. Having one file for a part of beamline (e.g., a few sectors) and one for the entire ring will yield incorrect results.
  • -charge, -particles -- Give the charge (in nanocoulombs) or the number of electrons.
  • -coupling -- Give the emittance coupling ratio, $\epsilon_y/\epsilon_x$. This is used to compute the horizontal and vertical emittance from the natural emittance.
  • -RF=Voltage=MV,harmonic=value -- Specify rf voltage and harmonic number. N.B.: If the data files cover only a portion of the ring, using this option will give incorrect results!
  • -length=mm -- Specify the rms bunch length. This is an alternative to giving rf parameters.
  • -emitxInput -- Give the initial x emittance in meters. If not specified, the value from the parameter ex0 in twissFile is used.
  • -deltaInput -- Give the initial rms fractional momentum spread. If not specified, the value from the parameter Sdelta0 in twissFile is used.
  • -verbosity -- If nonzero, program execution information is printed to the standard output.

• author: A. Xiao, ANL/APS.