Abstract New prompt fission neutron spectrum measurements are reported for 235U( n , f ) reactions induced by neutrons with energies from 0.7 to 20 MeV. These measurements cover outgoing neutron energies from 2.5 MeV down to 10 keV, using an array of 6Li-glass scintillators for neutron detection and a double time-of-flight technique. The neutrons were produced at the Weapons Neutron Research facility of the Los Alamos Neutron Science Center. A detailed MCNP® model of the experimental equipment and the surrounding room was used to interpret the experimental results. Backgrounds were measured in situ, making use of the time-dependent singles rates of the various detectors with asynchronous readout from waveform digitizers. The results presented here have been included in a re-evaluation of the fission neutron spectra for this fissioning system, a description of which is presented elsewhere in this issue.

中文翻译：

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对于 0.7 到 20 MeV 的入射中子，235 U( n , f ) 低于 2.5 MeV 的快速裂变中子谱

摘要 对能量为 0.7 至 20 MeV 的中子引起的 235U( n , f ) 反应进行了新的瞬发裂变中子能谱测量。这些测量涵盖了从 2.5 MeV 到 10 keV 的输出中子能量，使用了用于中子检测的 6Li 玻璃闪烁体阵列和双飞行时间技术。中子是在洛斯阿拉莫斯中子科学中心的武器中子研究设施中生产的。实验设备和周围房间的详细 MCNP® 模型用于解释实验结果。背景是在原位测量的，利用各种检测器的时间相关单波率和波形数字化仪的异步读出。此处介绍的结果已包含在对该裂变系统的裂变中子谱的重新评估中，