Gamma-Ray Spectra of Fission Products Observed with Lithium Drifted Germanium Detectors

The γ-ray spectra of fission products from thermal neutron irradiation of natural U were observed with an encapsulated Ii-drift-Ge γ-ray spectrometer. The spectra were recorded at various periods after irradiation—1, 2, 5, 12, 30, 250 days and 3 years. The γ-ray spectra of eight individual fission products including ²³⁹Np were also studied. Due to the high resolution obtained with the detector, many nuclides were identified which would have been undetectable without resorting to chemical separation.