The Flux widget calculates the total flux (in units of ph/s) and power (in Watts) after any ShadowOui optical element or at sample position. This is done by calculating the source spectrum and convolving with the beamline energy-dependent transmittance calculated with ShadowOui.
The Bending Magnet and Wiggler spectrum is calculated analytically as in X-ray Data Booklet. The correct (not gaussian approximation) vertical angular distribution of the source is computed to account for partial acceptance of the vertical divergence. This enables optimization of the simulation when the beamline vertical acceptance is not total.
The Linear Undulator (elliptical undulator is to be implemented soon) source spectrum is calculated numerically using SRW (Synchrotron Radiation Workshop) code (see ref. [1]), taking into account the energy spread and finite emittance of the electron beam. SRW is natively shipped with OASYS1 and should be enabled.
See the Examples Folder for a few examples and usage tips of the Flux Widget.
To use Flux Widget, just link the desired optical element (or source) widget to the Flux Widget and modify the parameters corresponding to the source.
IMPORTANT NOTE: In Calculation Settings tab, the user must define the source vertical and horizontal acceptance range where the flux will be calculated. Usually, the acceptance limits must the same as those defined at the source widget. However, when using bending magnet and wiggler sources, the source divergence distribution may have rays outside the defined limits. In this case, the user must adjust the acceptance limits on the Flux Widget, so that its spectrum corresponds well to the Shadow distribution. To degub the results, all the intermediate steps of the calculation are shown in other tabs (Source Spectrum, Beamline Transmittance, Histogram, Source Acceptance and Output)
[1] O. Chubar and P. Elleaume, Proc. EPAC-98, 1177 - 1179 (1998).