The prompt γ -ray spectrum of fission fragments is important in understanding the dynamics of the fission process, as well as for nuclear engineering in terms of predicting the γ -ray heating in nuclear reactors. The γ -ray spectrum measured from the fission fragments of the spontaneous fission of 242 Pu will be presented here. A fission chamber containing in total 37mg of 242 Pu was used as active sample. The γ -quanta were detected with high time- and energy-resolution using LaBr 3 and HPGe detectors, respective…