I want to define continuous x-ray spectrum of tungsten struck by electrons manually because of statistical reasons. I need three things for this;
I need to define surface for source because of x-rays not coming out from a point, also I need to define this surface with angled,
I need to define x-ray energy spectrum with using energy bins and probabilities, which I get from FLUKA with simulating electron beam hitting tungsten,
I need to define intervals of polar angle and azimuth angle because of I want to use only one part of x-ray distribution.
This is not a very straightforward issue, so let me tackle the options.
You are probably best off defining several sources to cover different radiation angles with help of the BEAMSPOT, SPOTBEAM and SPOTPOS cards. The sources in FLUKA can have transverse size, so they are not necessarily point-like. They can be set e.g. with Shape(X), Shape(Y), DeltaX and DeltaY entries in the SPOTPOS card.
If you want to define the beam only for a fraction of the solid angle of a sphere, this can done via the definition of the beam with the cards mentioned in point 1. Otherwise, if you want to have the beam everywhere, but to score the results only in some specific region, please assign the scoring card only to the geometrical region you are interested in.
On another point: If your concern for the simulation to be performed with tungsten target and electron beams is statistics, it might be easier to solve it by biasing. Did you consider it?
I hope this helps and please write us if more input is needed.
Firstly, thank you for your reply. I will check options that you suggest. Well actually I thought about biasing, but unfortunately I never used biasing neither in FLUKA nor another MC simulation programs. So, I am not sure about the capabilities of biasing and I do not know how to use biasing. Is it possible to define x-ray beam, which is result of electrons struck to tungsten, only for a fraction of the solid angle of a sphere with biasing?
biasing helps you to get higher statistics for some processes or, what is more relevant in your case, for some regions. E.g. you can define a surface at which the particles are “split”, but are counted with their corresponding weights, so that the fluence or dose you calculate with this method is automatically normalized to the correct value by FLUKA. For that you can use BIASING card, defining two regions, on the border between which the particles can be split. The biasing factor can be set by the “importance” (Imp) number assigned to the regions, with the maximal difference between the neighboring regions being a factor of 5. So if you are interested in a solid angle in a specific direction from the surface, you can define this solid angle as a region and separate it radially in two or more regions, using the biasing on the transition surface between these radial regions.
I hope this explanation was clear, please write us if it is not the case.