Measurement and Analysis of Neutrons Emitted from Fission of Transuranium Nuclides

1.通过同时测量两个裂变碎片的速度和能量，得到了Pu-239热中子裂变的平均瞬发中子数与碎片质量数的函数关系。设计并完成了一套新的裂变碎片和瞬发中子同时测量系统。3.利用京都大学反应堆（KUR）的超反射镜中子导管、薄样品层裂变室和上述系统，测量了U-235和U-233的裂变碎片质量和能量以及瞬发中子数和能量。利用实验结果研究了裂变过程中的质量和能量分配。4.建立了一个新的瞬发裂变中子能谱计算程序系统，并编制了Np-237、Cm-242、-243、-244、-246、-248的瞬发裂变中子能谱计算程序。6.利用Moriyama公式和一些实验数据，研究了锕系核素缓发中子产额的系统性，并解释了高锕系核素缓发中子产额减少的原因。

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.