Dear expert
I am currently conducting an electron beam bombardment to convert the target material tungsten into photons, which then undergo a 226Ra (g, n) 225Ra reaction and finally decay to 225Ac. I have encountered the following error message
When I added the LOW-MAT card, the reaction occurred. However, I think this utilizes the low-energy neutron cross-section that does not belong to Ra. I realize that the calculation result is unreasonable. If so, how should I modify it?
At the same time, I obtained the specific activity after irradiation through the RESNUCLE card. 225Ac was generated inside. Was it produced through the decay of 225Ra? Does the specific activity in RESNUCLE cards take decay into account?
Finally, I saw on the forum that FLUKA currently doesn’t have the ability to study the 226Ra (g, n) 225Ra reaction. Ac-225 production - Geometry and Materials - FLUKA User Forum
You did not see well. In that 2020 post, it was explained that neutron re-interactions in radium could not be performed (now they can, as @horvathd pointed out), but the (g,n) reaction generating the neutron could already be simulated.
I am calculating the reaction processes of 226Ra(γ, n)225Ra and 68Zn(γ, p)67Cu. Different reactions encountering different neutron libraries will result in different errors. For instance, Re and Zn will report errors in CENDL-31 and JENDL-4.0
This is because my reaction is quite unique. There are no low-energy neutron cross-sections of the corresponding materials in some of the libraries, so an error is reported?
Dear expert
I have downloaded some of the neutron libraries as shown in the figure. Selecting some neutron libraries will cause the calculation to fail, which is exactly what I want to ask you for advice
Meanwhile, I would also like to ask, if the latest version introduced a new point-wise treatment of low energy neutrons, then in what circumstances should LOW-MAT be used？
The default neutron library for FLUKA is the JEFF-3.3. I would recommend to use that one
Can you please elaborate more the “cause the calculation to fail”?
What is the error reported in the output, error or in log file?
Can you post your input, output files, log files?
Dear expert
I am calculating the reaction processes of 226Ra(γ, n)225Ra and 68Zn(γ, p)67Cu, and studying the influence of different neutron libraries on the calculation results. I have found that 226Ra(γ, n)225Ra will have calculation errors when encountering the BROND-3.1 and CENDL-31 neutron libraries. 68Zn(γ, p)67Cu will have computational errors when encountering CENDL-31 and JENDL-4.0 libraries. The error report is as follows:
Ra.inp (3.9 KB) Zn.inp (10.6 KB)
Could it be that because my reaction was unique and there were no low-energy neutron cross-sections of the corresponding materials in some libraries, an error was reported?
For (γ,n) and (γ,p) processes you don’t need any of the above databases.
These databases are only used for neutron induced reactions E<20MeV
I would recommand to use the default library JEFF-3.3 for neutrons (so the code will not complain for missing isotopes)
and enable also the Photo nuclear reactions. You have activated only the electro-nuclear
Dear expert,
226Ra (γ, n) 225Ra generates neutrons, which may affect other reactions in the experiment and thus influence the generation of other nuclides. I wanted to simulate the same result as in practice as possible, so I activated the neutron library. Meanwhile, when I turned off the neutron library, FLUKA would automatically open the LOW-MAT card for me. Does this card need to be kept
The Settings of my PHOTONUC card are as follows. According to the manual’s explanation, this should enable all energy levels of the photonuclear reaction. If I fail to enable it, could you please tell me how I should do it?
