Cartoons of an HTSU10 undulator. This cartoon shows how the flux-density curves (5 - 60 keV) change as the magnetic-field amplitude between the magnet arrays on axis increases. This is accompanied by an increase in integrated intensity (how opaque the x-ray beam is); an increase in electron-beam oscillation amplitude; an increase in solenoid current (shown by the ammeter); and a reddening of the HTS magnet half-moon blocks. The spectra are plotted with a logarithmic ordinate axis. Note that in practice, one never applies the solenoid field during operation of the storage ring.
Two additional animations are provided (without code; it’s extremely similar) in which the magnets slowly exhibit a flux-density distribution across their faces, and the x-axis of the undulator spectrum is also shown.
The parameters used to generate the undulator spectra in SPECTRA are:
Storage-ring energy = 2.7 GeV
Current = 400 mA
Circumference = 288 m
Bunches = 480
Natural emittance = 150 pm.rad
Coupling constant = 0.002
Energy spread = 0.0011
beta_x,y = 2.5, 1.28
All other accelerator constants = 0
B = 0.01 - 2 Tesla in 0.01-T steps (this appears not to be a variable parameter, hence I took 200 linear steps in K from 0.01 to 1.86746, as this maximum value corresponds to B = 2 T).
lambda_u = 10 mm
Device length = 1 m
End Correction Magnet: activated
Far field and ideal conditions: energy dependence of partial flux through a rectangular slit 1 x 1 mm2 at 30 m, slit position @ 0,0.
5000 - 60000 eV, 1-eV steps
Many thanks go to Marco Calvi, PSI for assistance in generating the spectra.
Cartoons of a high-temperature superconducting undulator