Dear FLUKA experts
My goal is to simulate the gamma-ray pulse height spectrum of an Am-241 radioactive source in a NaI(Tl) detector. I try to achive that with the BEAM card with an ISOTOPE particle, the HI-PROPE card defining Am-241 and the RADDECAY card to define the semi-analoge mode. As you for sure all know, FLUKA simulates the entire decay chain of a radioactive isotope, i.e. not only the promt decay radiation but also the decay radiation from the daughters, grand-daughters,… of Am-241. In my case however, my source is (approximatly) pure Am-241. So, I would like to simulate only the promt decay radiation of Am-241. How can I achive that?
So far, I came up with two solutions:
- Simulate the parent (Am-241) and the daughter (Np-237) separatly and subtract the daughter spectrum from the parent spectrum. This is not very appealing due to the introduction of additional statistical uncertainties. So I would prefer another solution.
- Use the usrmed.f user-routine, i.e. kill all radiation products except those coming from the Am-241 decay. I edited and tested a routine published by Androulakaki (Implementation of FLUKA for γ-ray applications in the marine environment - ScienceDirect). However, I’m not sure, if this routine really does what I want. As I already said, I would like to transport all promt decay radiation from Am-241 (gamma-ray, X-ray, alpha,…) but no decay radiation from its decay products (Np-237,…). In the context of the published routine, I have the additional questions: What are the differences between ATRACK and Agestk? What are the differences between LTRACK and Iprodc?
Do you have a better solution or could you maybe tell me, how I can improve the usrmed.f user-routine?
Bonus question: Is there a way to simulate the radiation of a decay chain of a parent isotope after some predefined time in 1 simulation, e.g. the decay radiation of an Am-241 source after 100 years since its creation (including the decay radiation from the daughters, grand-daughters,… , which were created by the decay of Am-241 during the 100 year period)?
Notes: For your convenience, I attach a test input script and the user-routines usreou.f (to score the energy deposition in the NaI detector) and usrmed.f (to kill all delayed decay radiation, actived by the MAT_PROP card).
Thank you all in advance for your support