Dear all,
I want to calculate the yield of Zr-89 produced by irradiating Y89 with 13 MeV proton. This is the input file. Y89.inp (3.5 KB), and this is the output file. Y89_53_sum.lis (1.9 KB)
First, IRRPROFI is used to give the intensity. So,does ‘Total response is 1.64976 e-4’ in output file take into account the intensity? The same question is also appeared in the ‘Residual neclei distribution’.
Second, the nuclei of A/Z in the output file are 39/90, 39/40, and 40/89. However, what does A/Z=1/1 mean?
Third, there should be the nuclei of A/Z= 39/88,39/86 in the calculation, but in fact there is none. Therefore, is this caused by the input card writing incorrectly or by the lack of a related neutron library?
Fourth,how to produce the FLUKA neutron library, or where can get the latest library?
Yes. Not only the intensity, but also the decay time, which you have selected as zero in your input. By the way, I do not see a RADDECAY card in your input although I am sure you had it, otherwise you would not have gotten any decay products. Just make sure it is there.
Here I guess you mean A/Z = 90/39,89/39 and 89/40. A/Z = 1/1 means residual nuclei with A=1 and Z=1: hydrogen nuclei (i.e. protons).
I can see that both isotopes appear when increasing the proton energy, are you sure they should appear also for 13 MeV protons? If so I will take a closer look and come back to you asap.
1，According to the results of IAEA, 88/39 will be produced, but the yield is seven orders of magnitude lower than 89/40.
2, The low-energy neutron cross section is very important for the calculation of the yield of Zr-89 (Y target) and Cu-64(Ni-64 target). However, there is not the cross section of Ni-64 in the neutron library. So, how can I get the neutron section of Ni-64? Or where can I find the format of the neutron cross section library and how to prodcue the neutron cross section by NJOY or PROPRE?
Hi,
you are talking about (p,n) reactions, where low energy neutron cross sections, which refer to neutron induced reactions (n,*), have no relevance at all. The job here is done by the FLUKA interaction model for proton induced reactions, for which no library is needed.
For an expected production yield seven orders of magnitude lower than the reaction cross section, one can hardly obtain a sensible result from a Monte Carlo calculation (I start to get a meaningful 88Y yield for a proton energy of 15 MeV).
Dear Francisco.
Thanks a lot for your response again.
1， Yes, you are right. In the calculation of the yield of Cu-64(Ni-64 target), (p,n) reaction should be taken about. However, when I remove the LOW-MAT card and modify the MATERIAL card of NI-64 shown in the fig. The errors will be print out: Low energy neutron xsec not found for some medeia ，NI64. So, how to slove this problem?
2, In FLUKA, I find neutron cross section library, MATERIAL,Elastic cross sections library,Elastic cross sections library and so on. But ,I can not find (p,n) cross section. Therefore, whether (p,n) cross section is called in transport calculation of Ni-64. If it was used, where I can find it or how can I output the (p,n) cross section?
Assuming that, as discussed, your goal is not sensitive to neutron reactions in Ni-64, you can input a LOW-MAT card to make use of the neutron cross sections of natural nickel in your NI-64 material slice, which are included in the FLUKA library.
Note that the MATERIAL card defining COPPER is useless, since COPPER is a pre-defined material, and that in the MATERIAL card defining NI-64 the first 64.0 occurrence should be avoided, as recommended in the manual, since the atomic weight of Ni-64 is not exactly 64.0 and FLUKA already knows it (therefore you need to specify only the mass number 64.0 in the last numeric field (WHAT(6)).
As I already wrote above, for proton induced reactions FLUKA does not need any library, since it calculates the respective cross sections runtime. In the output file (.out) you can find a material table where the inelastic scattering length of beam particles (13 MeV protons in your case) is printed. From that you can easily obtain the respective reaction cross section (the inelastic scattering length is the inverse of the macroscopic cross section, which is related to the microscopic cross section). As for the cross sections of specific channels, these are not intended for direct printing. Still, the (p,n) one will be reflected by the Cu-64 production yield in Ni-64, which is given by a RESNUCLE card not associated to any cooling time.
For nuclide yield calculation purposes, I recommend you to use a LAM-BIAS card (WHAT(2): biasing factor for hadronic inelastic interactions) in order to improve the statistics of proton reactions in the thin Ni-64 slab.
