A simple source model emitting photons from a gaussian distribution in the X-Y plane with the specified
standard deviations (in mm). A square target centered on the beam (Z-axis)
restricts the beam to that aperture.
Further, the beam is restricted to emit photons between E0+-dE keV, or lambda0+-dlambda, whichever is given.
Flux is given in the unit
Example: Source_gaussian(sig_x=10e-6,sig_y=10e-6,dist=15,sigPr_x=9e-6, sigPr_y=9e-6,E0=sensible, dE=sensible)
Parameters in boldface are required;
the others are optional.
Horizontal source size
Vertical source size
Angular horizontal divergence
Angular vertical divergence
Distance from source plane to sampling window.
Width of sampling window dist m downstream from source to allow focused sampling.
Height of sampling window dist m downstream from source to allow focused sampling.
Center of emitted energy spectrum (overrides spectrum_file)