11.13 sddsbrightness

• description: sddsbrightness computes undulator brightness curves using Twiss parameter data from elegant or sddsanalyzebeam. Several calculation methods are available.
• examples:

  sddsbrightness run.twi run.bri -harmonics=3 -Krange=start=0.2,end=2.2,points=100
  -current=0.1 -totalLength=2.4 -periodLength=0.027 -coupling=0.01

  sddsanalyzebeam run.out -pipe=out -correctedOnly
  | sddsbrightness -pipe=in run.bri -harmonics=3 -Krange=start=0.2,end=2.2,points=100
  -current=0.1 -totalLength=2.4 -periodLength=0.027 -coupling=0.01

• synopsis:

  sddsbrightness [-pipe=[input][,output]] [twissFile] [SDDSoutputfile] -harmonics=integer -Krange=start=value,end=value,points=integer -current=Amps -totalLength=meters -periodLength=meters [-emittanceRatio=value | -coupling=value] [-noSpectralBroadening] [-method=string,device=string,neks=value]]

• files:
  • twissFile — A Twiss output file from elegant, with radiation integral calculations included, or an output from sddsanalyzebeam. In the latter case, the -correctedOnly option should be used.
  • SDDSoutputFile — Contains the brightness data in column form. For each requested harmonic i, there are columns photonEnergyi, wavelengthi, and Brightnessi.
• switches:
  • pipe — The standard SDDS Toolkit pipe option.
  • harmonics — The number of harmonics to compute.
  • Krange=start=value,end=value,points=integer — The range of the K parameter for the undulator and the number of points to compute on that range.
  • -current=Amps — The current in amperes. If one gives the average current, one gets the average brightness.
  • -totalLength=meters — The total length of the undulator, in meters.
  • -periodLength=meters — The period length of the undulator, in meters.
  • -emittanceRatio=value | -coupling=value — In the case of a twiss output file from elegant, which does not contain the vertical emittance, one must supply one of these options. If -emittanceRatio=R is given, ϵ_y = ϵ₀ * R and ϵ_x = ϵ₀; this isn’t how things work physically, but is provided for historical reasons. If -coupling=k is given, ϵ_x = ϵ₀∕(1 + Jy * k∕Jx) and ϵ_y = k * ϵ_x. ϵ₀ is the equilibrium emittance from the twiss output of elegant.

    In the case of twiss output from sddsanalyzebeam, both emittances are present and these options are ignored.

  • -method=string[,device=string][,neks=value][,detuning=value] — Choose which method to use for brightness calculations. Options are
    • borland — M. Borland’s approximate method. Deprecated. Use Lindberg’s method if a fast approximation is desired.
    • dejus — R. Dejus’ non-zero emittance, infinite-N+convolution method. This is the default.
    • walkerinfinite — R. Walker’s method. Dejus’ method is derived from this method.
    • walkerfinite — R. Walker’s method using finite N without convolution. This is quite slow.
    • lindberg — R. Lindberg’s method. About 20 times faster than Dejus’ method. Provides central cone flux in addition to brightness. Provides control of detuning.

    The device qualifier may be planar or helical. neks is used to change the number of points used for finding the peak of the distribution.

• authors: M. Borland, R. Dejus, X. Jiao, R. Lindberg, H. Shang, R. Soliday (ANL).