RPP Source Definition and Visualisation

Source Definition
1

Dear Experts,
I am defining a RPP source with dimensions 310 cm x 0.6 cm x 216 cm along XYZ centered at (0,0,0). I have defined this source using BEAMPOS as below:

image
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  1. Is the source definition correct?
  2. I am trying to plot the source using USRBIN card ( Part - BEAMPART and Type - X-Y-Z )
    Case I. USRBIN x-y-z extents are same as the source dimensions:

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The plot is obtained as:
image

Case II. USRBIN x-y-z extents are larger than the source dimensions:

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The plot obtained in this case

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image940×640 256 KB

Why there is so much colour (intensity) difference along the source dimensions in the above two cases?

  1. In USRBIN card, what is the difference between the types - BEAMPART and PHOTON? I have obtained the same plots using these two cards.

Please guide.

Thanks and Regards
Jyoti

3

Dear Jyoti,

Thanks for your question.

At a first glance, your source implementation looks correct to me, and I would attribute the color difference in the two pictures only to the difference in the scale of the color band, to be checked.
Please, upload the .inp and .flair files of your project so that I can have a look at them.

Regarding your third point, when scoring BEAMPART you record the primary (source or beam) particles specified in the BEAM card (in your case photons), while when scoring PHOTON you are scoring all the photons passing through you scorer. The difference between the two lies in the fact that, with PHOTON, you score all photons passing through your scorer and not just those primary photons emitted by your source. Differences between the two should appear if there are available mechanisms to produce secondary photons. If your source is in vacuum for instance, you should not expect any difference.

I hope this starts answering your doubts,
Cheers,
Marco