Reactor As Neutrino Source Fission Material Fission Products Neutrons odd-odd nuclei Structural materials of reactor Electron capture or + decay ( neglected ) νe Emission Captured Mostly rich in neutrons ¯ Decay back to stable valley Anti-neutrino Emisson
Simplified reactor model Candidate isotopes: 50Cr in RC , SS & Zr-alloy; 54Fe in RC , SS & Zr-alloy; 58Ni in RC , SS& Zr-alloy; 112Sn in Zr-alloy; In SS: 50Cr --0.95%; 54Fe --4.2%; 58Ni --6.3%; 112Sn --0%. In RC: 50Cr --0.01%; 54Fe --0.1%; 58Ni --0.63%; 112Sn --0%. 51Cr + e- 51V + νe 55Fe + e- 55Mn + νe 59Ni + e- 59Co + νe 113Sn + e- 113In + νe Active mass of RC, SS and Zr-alloy(tons): 4967, 1040, 33
Simulation procedure Source neutron sampling; Neutron flux estimation; Position: from fuel material homogeneously; Energy: follow Watt fission spectrum; Neutron flux estimation; Track length estimation for flux simulation; Neutron capture probability be tallied;
Cross Check K-eff : Total neutron capture probability: Real value: 0.9~1; Simulated result on our model: 0.77; (little under estimated) Total neutron capture probability: ∑P n_capture = 1
Neutrino flux calculation In which: :ratio of neutron capture probability of the ith isotope in cell j to the total neutron capture probability of all the material in cell j : nuclei number of the ith kind isotope in cell j;; : neutron capture cross section of the isotope i in cell j, i=1,2…nj; : electron capture branch ratio of the (A+1) isotope , which is produced from the ith isotope with atomic mass A via neutron capture; : neutron capture probability of cell j; : neutron flux in jth. cell; j=1,2,…M;
Simulation Result Geometry distribution of neutron capture probability Simulated neutrino emission Spectrum ; Total neutrino emission rate normalized to per fission is: ~0.075 Correspond to an emission rate of 6 νe per fission on the energy range of < 1MeV ; ~ 10-2;