Emeritus, The Center for Peace, Hiroshima University, Hiroshima, Japan.
The Center for Peace, Hiroshima University, Hiroshima, Japan.
Front Public Health. 2024 Jan 17;12:1335097. doi: 10.3389/fpubh.2024.1335097. eCollection 2024.
Even today when nearly 80 years have passed after the atomic bomb (A-bomb) was dropped, there are still debates about the exact doses received by the A-bomb survivors. While initial airborne kerma radiation (or energy spectrum of emitted radiation) can be measured with sufficient accuracy to assess the radiation dose to A-bomb survivors, it is not easy to accurately assess the neutron dose including appropriate weighting of neutron absorbed dose. Particularly, possible post-explosion exposure due to the radioactive particles generated through neutron activation have been almost neglected so far, mainly because of a large uncertainty associated to the behavior of those particles. However, it has been supposed that contribution of such non-initial radiation exposure from the neutron-induced radioactive particles could be significant, according to the findings that the stable chromosomal aberration rates which indicate average whole-body radiation doses were found to be more than 30% higher for those exposed indoors than for those outdoors even at the same initial dose estimated for the Life Span Study. In this Mini Review article, the authors explain that such apparently controversial observations can be reasonably explained by assuming a higher production rate of neutron-induced radioactive particles in the indoor environment near the hypocenter.
即使在原子弹（A 炸弹）爆炸近 80 年后的今天，对于 A 炸弹幸存者所接受的准确剂量仍存在争议。虽然初始空气比释动能辐射（或发射辐射的能谱）可以用足够的精度进行测量，以评估 A 炸弹幸存者的辐射剂量，但要准确评估包括适当加权中子吸收剂量在内的中子剂量并不容易。特别是，由于与这些粒子的行为相关的不确定性较大，到目前为止，人们几乎忽略了可能因中子激活产生的放射性粒子引起的爆炸后暴露。然而，根据发现，对于那些在室内暴露的人，稳定染色体畸变率（表明全身平均辐射剂量）比那些在室外暴露的人高 30%以上，即使对于寿命研究中估计的相同初始剂量，人们推测这种来自中子诱导放射性粒子的非初始辐射暴露的贡献可能是显著的。在这篇综述文章中，作者解释说，通过假设在距爆心较近的室内环境中产生中子诱导放射性粒子的速率较高，可以合理地解释这种明显有争议的观察结果。
