Hiroshima and Nagasaki initial radiations: delayed neutron contributions and comparison of calculated and measured cobalt activations
Hiroshima and Nagasaki initial radiations: delayed neutron contributions and comparison of calculated and measured cobalt activations
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广岛和长崎初始辐射：延迟中子贡献以及计算和测量的钴激活的比较
DOI：
10.13182/nt85-a33577
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发表时间：
1985
影响因子：
1.5
通讯作者：
W. Loewe
中科院分区：
文献类型：
--
作者：
W. Loewe
对广岛和长崎原子弹幸存者接收到的中子剂量的计算估计没有包括碎片云中裂变产物发射的延迟中子的贡献，尽管有迹象表明这一来源可能有很大贡献。在目前的工作中，建立的解释这些裂变产物的伽马射线动能的模型被修改为提供所需的中子动能估计。适应包括使用中子发射器的显式时间依赖关系，适当地与爆炸本身的时间依赖现象相结合，以及在具有这些延迟中子的能谱特征的源的情况下详细的空中-地面中子传输。结果表明，延迟中子对原子弹幸存者剂量测定以及广岛的中子激活的贡献确实可以忽略不计。然而，在长崎，大约一半的激活是由于延迟的分量。计算的钴活度是对先前估计的修正，并与广岛和长崎的实测值进行了比较。文中还讨论了这些差异的原因，并与以前报道的硫活化度差异进行了比较。建议进行额外的调查。
Calculated estimates of neutron doses received by atomic-bomb survivors at Hiroshima and Nagasaki have not included contributions from delayed neutrons emitted by fission products in the debris cloud, although the possibility of a significant contribution from this source has been suggested. In the present work, an established model accounting for gamma-ray kermas from these fission products is adapted to provide the desired neutron kerma estimates. Adaptations include use of explicit time dependence of neutron emitters, properly folded with the time-dependent phenomenology of the explosion itself, and detailed air-over-ground neutron transport with a source having an energy spectrum characteristic of these delayed neutrons. Results show that delayed neutrons are indeed negligible contributors to atomic-bomb survivor dosimetry, as well as to neutron activations at Hiroshima. About half the activation at Nagasaki, however, is due to the delayed component. Calculated activation of cobalt, a revision of previous estimates, is compared to measured values at Hiroshima and at Nagasaki. The causes of the substantial discrepancies are discussed and compared to previously reported discrepancies for sulfur activation. Additional investigation is recommended.