Measurements of high-energy photonuclear reaction yields in the 2.5 GeV electron beam stop

Measurements were made for radioactive nuclide yields formed in Al, Fe, Cu and Nb foils by the irradiation of bremsstrahlung generated by ∼2.5 GeV electrons. The foils were inserted in a Cu beam stop and irradiated by electrons. For a comparison, calculations of the yields were carried out. The photon energy spectrum obtained by the EGS4 code was multiplied by the photonuclear cross sections evaluated by the PICA code at photon energies below 350 MeV, and by Rudstamʹs formula at higher energies above 350 MeV. It was found that the calculated values tended to overestimate the measured ones, especially for nuclides whose mass was moderately far from that of target nuclide.