Neutron production and energy deposition in fissile spallation targets studied with Geant4 toolkit

Neutron spectra produced by 30, 35 and 40 MeV proton beams at KIRAMS MC-50 cyclotron with a thick beryllium target

“…By using the same procedures, the gamma-ray activities of 24 Na produced through the 27 Al(n,α) 24 Na reaction were also obtained, and the relevant experimental cross-sections for 27 Al(n,α) 24 Na [47,[51][52][53][54][55][56][57][58] and the EAF-2010 data are shown in Fig. 7.…”

“…where σðE n Þ is the cross-section of the neutron induced reaction at neutron energy E n ; ΦðE n Þ is the flux of neutrons of energy E n , λ is the decay constant of a particular radioisotope produced, N is the number of target atoms in the sample (of 27 Al or 56 Fe), β is the branching ratio of the gamma-ray measured, and T CO is the cooling period after irradiation. The dead time correction is incorporated by taking into account the actual time T AT during which the gamma-ray activity was measured by a HPGe detector with MCA, and T CL is the time of counting as per the clock.…”

“…The neutrons with energies above the threshold for 27 Al(n,α) 24 Na and 56 Fe(n,p) 56 Mn reactions interacted with 27 Al and 56 Fe nuclei and produced 24 Na and 56 Mn, respectively.…”

“…GEANT4 is a particle transport code and is widely used for simulations in diverse scientific fields, such as medical physics [24][25][26], accelerator induced radiation [17,18,27], neutron shielding [28][29][30], and environment radiation [31][32][33][34]. The details of the GEANT4 code can be found on the web [35].…”

“…Aluminum foils and ferric oxide powder samples were irradiated with the neutrons. The activities of 24 Na and 56 Mn produced mainly through 27 Al(n,α) 24 Na and 56 Fe(n,p) 56 Mn reactions, respectively, at E p ¼ 30; 35; and 40 MeV were compared with the simulation results of neutron flux ΦðE n Þ multiplied by the evaluated crosssection σðE n Þ from the European Activation File, the EAF-2010 [23]. It is found that the experimental activities of 24 Na and 56 Mn agree with the calculated activities obtained from the neutron flux simulated by the GEANT4 code v10.0, which implies that the calculated neutron spectra seem close to the experimental spectra.…”