Effect of pulsed dose in simultaneous and sequential irradiation of V-79 cells by 14.8 MeV neutrons and 60Co photons

The effect of irradiating V-79 Chinese hamster ovary cells with a mixture of 40% 14.8-MeV neutrons and 60% 60Co photons with simultaneous or sequential exposures is investigated. Target doses are obtained by irradiating cell samples with 3-minute-long pulses of alternating neutrons and photons (in the sequential case) or with mixed neutrons and photons followed by equal beam-off periods to insure equal total-exposure times for sequenced and simultaneous irradiations. We observe qualitative differences between the survival results under each beam configuration that confirms earlier observations