Yield measurements for 7Be and 10Be productions from natCu, natAg and 197Au by bremsstrahlung irradiation at E0=200 MeV

The yields of 7Be and 10Be produced by bremsstrahlung having a maximum energy (E0) of 200 MeV in natCu, natAg and 197Au targets were investigated by the AMS technique at MALT of the University of Tokyo. It was found that the yields at E0=200 MeV were much lower than those at E0≥250 MeV, obtained in our previous works. A change in the yields of the fragmentation component in the target-mass dependence was observed at E0=200 MeV when compared with those at E0≥250 MeV. However, the ratios of the fragmentation yield of 10Be to that of 7Be remained unchanged throughout the concerned E0