The effect of the concatenated coincidence addition of gamma

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Dear FLUKA experts,
I want to know how to calculate the effect of the concatenated coincidence addition of gamma in FLUKA: I intend to compare the detection efficiency of single-energy gamma rays with that of isotopes with cascade gamma rays. A Semi-Analogue model in RADDECAY cards has been used to simulate isotope sources, and no cascading effects appear to occur in this model.
Thank you very much for your help and answer! Looking forward to your reply. Wish you the best of luck in everything.
Very thankful!!!
Lin

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Dear FLUKA experts,
I’m very sorry that I didn’t explain the problem clearly before. What I want to calculate is that when the detector is detecting, due to the existence of the signal resolution time, some nuclides may decay and emit multiple gamma rays within this time. Since this process occurs almost simultaneously, it is generally called cascade gamma ray emission.
My question is, in the FLUKA calculation, I have established the detector model and set up the isotope source. In the RADDECAY card, I have enabled the semi-analog mode. Does this isotope source decay process take into account the emission of cascade gamma rays? If not, how should I set it up? Because in the end, I want to compare the impact of the presence or absence of cascade gamma emission on the detector efficiency. I’m looking forward to your response.
Thank you very much for your help and answer! Looking forward to your reply. Wish you the best of luck in everything.
Very thankful!!!
improve.inp (3.8 KB)
Lin

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Dear @linjunze,

Your simulation input (isotope beam, RADDECAY card specifying semi-analogue mode) will indeed take into account the emission of cascade gamma-rays. However, as specified in the manual this happens in an uncorrelated way. This means that the different possible gamma rays are sampled from the yield distribution in the nuclear database of FLUKA and are in no way in direct correlation to the preceding decay in the chain. Since the different isotopes are defined in your input file, I assume that you are checking for each of those specific isotopes how much the cascade gamma rays contribute? You might need to sample many primaries to see the desired effect in a statistically converged way. Is this why you are not certain about your method of simulation?

I’m also happy to point you to two related but more detailed posts on this topic, one about printing info on primary and secondary particles produced in radioactive decay, and one about detailed scoring of the specific gamma cascade energy using an mgdraw routine.

Hope this helps, please let us know in case you need more information,

Andreas

1 Like
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Dear @anwaets ,
Thank you for your reply and help. Your answers are very useful. I will carefully read the two articles you gave. Thanks again and I wish you all the best.
Lin