Straume T, McDonald J C, Pederson R A, Brenner D J, Dobson R L
Lawrence Livermore National Laboratory, Livermore, California 94550.
Radiat Res. 1991 Nov;128(2):133-42.
The lineal energy distribution and several other dosimetric parameters were measured for the neutrons emitted from a replica of the Hiroshima bomb to determine their usefulness in biological experiments designed to estimate the effectiveness of actual Hiroshima neutrons. The "Little-Boy" replica (LBR) was constructed at the Los Alamos National Laboratory in support of the recent atomic-bomb dose reevaluation and was made of identical materials and had nearly identical dimensions and geometry as the Hiroshima bomb. However, the LBR was operated as a steady-state nuclear reactor, which permitted measurements under controlled conditions. Detailed dosimetric measurements and calculations were made at distances of up to 2.1 m from the center of the LBR uranium core. At these distances, the in-air kerma was approximately 97% from neutrons and kerma rates were shown to be particularly useful for biological experiments (up to approximately 7 Gy/h was possible). Quantitative intercomparisons of neutron energy spectra, lineal energy distributions, and measured cytogenetic results for several fission-neutron sources indicate that Hiroshima and LBR neutrons should be of similar biological effectiveness. Based on these evaluations, and cytogenetic results for LBR neutrons reported in a companion paper (this issue), it is estimated that Hiroshima neutrons were 20 to 30% more effective than the fission neutrons commonly used in radiobiology.
测量了广岛原子弹复制品发射的中子的线能量分布和其他几个剂量学参数，以确定它们在旨在评估实际广岛中子有效性的生物学实验中的效用。“小男孩”复制品（LBR）是在洛斯阿拉莫斯国家实验室制造的，以支持最近的原子弹剂量重新评估，它由相同的材料制成，尺寸和几何形状与广岛原子弹几乎相同。然而，LBR作为一个稳态核反应堆运行，这使得能够在受控条件下进行测量。在距离LBR铀芯中心最远2.1米的地方进行了详细的剂量学测量和计算。在这些距离处，空气中比释动能约97%来自中子，并且比释动能率被证明对生物学实验特别有用（最高可达约7 Gy/h）。对几种裂变中子源的中子能谱、线能量分布和测量的细胞遗传学结果进行的定量比对表明，广岛和LBR的中子在生物学有效性方面应该相似。基于这些评估以及在同一期的一篇配套论文中报告的LBR中子的细胞遗传学结果，据估计，广岛中子的有效性比放射生物学中常用的裂变中子高20%至30%。
