The Detailed Source provides the user with all the available source definition options in FRED. The Detailed Source dialog has multiple tabs, each of which allow specification of certain source parameter types. The available tabs are:
FRED offers a great deal of power and flexibility in the defining of sources, but with that flexibility comes the possibility of ambiguity and misunderstanding. Source definition confusion can be avoided with an understanding of the ray generation rules. The user can define the source in any order but when the user asks FRED to Create Rays, the ray generation recipe ALWAYS follows these five steps in strict order for each source.
•The requested number rays are positioned with each ray having the same power summing to unity power. •The ray directions are set. •Each ray’s flux is scaled according to the position apodization. •Each ray’s flux is scaled according to the direction apodization. •Al of the ray fluxes are scaled to meet the total integrated power.
This last step can cause some confusion. For example, lets say that a plane wave is defined with an angle f to the normal of the surface containing the grid of rays. Then if the user selects Lambertian direction apodization, the rays would be scaled by cos(f). But the last step would rescale all the rays back to total power requested by the user. This is because the total power is the total integrated power of the rays as they are defined and not the total integrated power of the rays if they were directed along the source grid surface normal.
See Create New Detailed Source.
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