To Örebro University

In this paper we report on new spectral prompt gamma-ray measurements from the spontaneous fission of Cf-252 and thermal neutron-induced fission of U-236*. In both experiments, fission of U-236*. In both experiments, gamma-ray multiplicities, average and total gamma-energies were extracted. gamma-ray multiplicities, average and total.-energies were extracted. Apart from one recent measurement on Cf-252, about four decades have passed since the last dedicated experiments were reported in literature. Hence, there was a need for a revision, not only with respect to high priority nuclear data requests by the Nuclear Energy Agency (NEA). In the first mentioned experiment we have measured prompt fission gamma-rays with both cerium-doped LaBr3 and CeBr3 scintillation detectors, which both exhibit excellent timing and good energy resolution. The results from both detectors are in excellent agreement with each other and confirm the historical data. In the experiment on U-235(n(th), f) we employed cerium-doped LaCl3 detectors, together with the lanthanum bromide detectors mentioned above. Even here the first results indicate a good agreement with data from the early 1970' s. They are also in accordance with data in evaluated libraries like ENDF/B-VII.0, while this is not the case for Cf-252(SF). Hence, here an update is strongly recommended.