But I can't find (free) lead and muon fission datas to study.
eros: Extract from : https://researchbank.rmit.edu.…/rmit:161164/Turnbull.pdf (MUON INTERACTION WITH LEAD SHIELDING PRODUCING ACTIVATION: IMPLICATIONS FOR GAMMA-RAY SPECTROMETRY. )
You can also try at : https://researchbank.rmit.edu.au/view/rmit:161164
Muons do have at least 105 MeV of energy, but what counts is what is on top of that 105 MeV and whether they are polarized. You will noticed that lead is very bad for stopping, as mostly neutrons are produced, what you really don't like. Any material with a low Z is preferred!!
If you have a giger counter, then just use a copper plate between the reactor and the Giger. If counts increase, then you see muons if not, then they are not dominant.
Extract:
Muons are slowed then captured in the atomic K shell orbit of a nucleus. Various electromagnetic processes occur in this orbit such as Bremsstrahlung allowing the muon to drop down to the inner orbital 1s, then the muon either decays or undergoes nuclear capture. At low atomic number (Z < 11) the muon capture process dominates, whereas around (Z = 11), the probabilities of capture and decay are approximately equal, however, for high Z nuclei (e.g. Lead) the muon capture processes again dominate [48]. After capture the nucleus de-excites by the emission of a neutron and neutrino from the nucleus [18]. The resulting atom is known as a muonic atom.
This process is the dominant source of tertiary neutron production at shallow to moderate rock depth. With a high Z material such as lead, the probability of muon capture is proportional to Z4 [13].
The second process is direct muon induced spallation where a heavy nucleus ejects large numbers of nucleons (neutrons in this case) resulting from collisions by protons from cosmic rays. In addition there is photon induced spallation of muons whereby photons produced in muon showers cause the spallation of the neutron [49, 50].
