Measurement and Analysis of Neutrons Emitted from Fission of Transuranium Nuclides

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1.Average number of the prompt neutrons per a thermal neutron fission of Pu-239 was obtained as a function of fragment mass number by means of simultaneous measurement of velocities and energies of two fission fragments. The result agreed with the predicated value by using the Brosa's multimode fission model.2.A new simultaneous measurement system of fission fragments and prompt neutrons was designed and completed. Its characteristics were obtained.3.By making use of a supermirror neutron guide tube of Kyoto University Reactor (KUR), a fission chamber with a thin sample layr and the system described above, the mass and the energy of fission fragments and the number and the energy of prompt neutrons for U-235 and U-233 were measured. By using the experimental results, the division of mass and energy in the fission process was investigated. In addition to this, the level density parameters for fission fragment nuclides were obtained by the results.4.A new computer program system for the calculation of prompt fission neutron spectra, and those for Np-237, Cm-242, -243, -244, -246, -248 were obtained by this system.5.The Brosa's multimode fission model was applied to calculate the prompt fission neutron spectra. The obtained spectrum of the fast neutron fission of Np-237 satisfactorily agreed with the measured.6.By using Moriyama's formula and some experimental data, the systematics of delayd neutron yield of actinoide nuclides were investigated and applied to explain the reason of their decrement for higher actinoids.